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My Barn Twins

Discussion in 'Airheads' started by fxray, Feb 26, 2015.

  1. fxray

    fxray Long timer

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    ^^^ Thanks Nate. I'm honored that your first post on advrider is to this thread. I was just over on DTT catching up on what I missed last Thursday with your Triumph. Looks like I should have made more effort to show up. At the rate you are moving, you might have that thing done by next week. Between the vapor blasted alloy, your polishing, the paint work from Morrie's Place, and the careful fit-up of all the bits and pieces, your bike leaves me searching for the right word. I guess that word is exquisite!
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  2. Disston

    Disston ShadeTreeExpert

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    It's Airhead with a capital A.

    Welcome to the asylum.
    3DogNate likes this.
  3. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

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    I was just there last night.

    [​IMG]
    fxray likes this.
  4. fxray

    fxray Long timer

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    Wow, CDD, thanks for the pics! That is pretty impressive. Were you getting some work done, picking up parts, or just checking the place out?
  5. crazydrummerdude

    crazydrummerdude Wacky Bongo Boy

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    Checking the place out. They had an official grand opening with food, music, etc. They sell some nice machined bits.
  6. fxray

    fxray Long timer

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    Well, today was sort of like Christmas in November, with stuff coming in from several places. Ed Zender mailed me down a new rear drive chain for the '64 TR6R from Morrie's Place up in Ringwood IL. I think the old one would have lasted a little longer if I had been a little more religious with the chain wax. I did pretty well right up until the past month or so, but now it is really toast. I am certainly glad I caught it before it wadded up and took a chunk out of the cases. (I've seen horrible pictures of that before.) The old one ran 7,000 miles.

    [​IMG]

    Ed also sent me that nut and washer in the little baggie to replace the one I must have forgotten to tighten after the last chain adjustment. The old one had vibrated off and was gone -- the only piece I have lost off my British bike, and I'm pretty sure it was my fault. You can't just run to Ace Hardware and pick up a 7/16-26 CEI nut, but Ed had one right there handy. Oh well, all it does is hold the front end of the reaction bar for the back brake. :eek7

    That sounds worse than it is, since the bolt is pretty well a captive, but I hate to think of the consequences if it had come out.

    Then I picked up a grunge brush for the chain. Maybe I will do a better job of keeping the new one clean. That came from Dennis Kirk, a very good supplier in my mind. They always ship in a timely way and will help on the phone if necessary.

    The brown box behind the brush has new tubes and rim strips for the Triumph, also from Dennis Kirk. I have been using IRC tubes on that bike since I got it running and I like them so I got some more. The thing I like is -- they hold air. That sounds like a dumb thing to say, but I hardly ever have to add air to my Triumph tires. The little Honda runs natural rubber tubes from Heidenau, and I need to add air a couple times a week. There are no holes in them; that's just due to the slight porosity of natural rubber tubes. They are a little heavier duty though.

    Then the big box under the other stuff is a pair of new Avon's for the TR6. This will be my first tire change this year, and the first I've had to mess with the Triumph tires since 2011. I'm not really looking forward to those two rim locks on the back wheel, but I did it once. I should be able to do it again. I thought about getting a pair of Avon Roadriders, but decided to stay with Speedmasters. Lots of people sneer at those, but my last set has done me proud . They gave good service with no cupping or weather checking; they're easy to clean, and I love the way they look. I ran the last set 7,000 miles and they are not worn out, they are just old enough that I will take them off.

    Then, all in the same day, there was a USPS box that looked familiar. It was my driveshaft back from Oshmo in Van Nuys. They told me on the phone it was headed my way. The man chuckled about my packaging but said it was very effective and he re-used it to send it back. The shaft was in padded plastic, inside the tube, which was in an "if it fits, it ships" box:

    [​IMG]

    Here's a closer look at the U-joint that they rebuilt:

    [​IMG]

    [​IMG]

    If I had to sum up in two words my experience with Oshmo, and my evaluation of the work they did, I would say, "Absolutely perfect!." Seriously, the U-joint has zero excess motion side-to-side or radially in any direction, yet it moves very smoothly. The keeper disks that they welded in over each bearing cap fit just right. I am more than pleased with this repair. Cost was $160.00 plus $14.00 shipping each way.

    Along these same lines, I took my Cycle Works driveshaft tool to a friend's house and we popped the bell off his driveshaft that had a failed U-joint. Once again, the Cycle Works tool made easy work of it. I thought this was supposed to be difficult. :hmmmmm I know, some of them can be really stubborn, but I do recommend that tool. I've used it twice with good results and no sweat.

    My swingarm isn't back yet from the powder coat shop, but he should have it ready soon. I don't really need it yet -- I have tires to change!

    Looks like break time is over.

    Ray
  7. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    I wonder why Oshmo doesn't make the u-joint serviceable/replacement using the circlip method HMPGuy uses...
  8. fxray

    fxray Long timer

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    That is certainly another option that I considered, but I am relatively sure that this U-joint will long outlive me. If it needs to be replaced again, the welds are easier to remove than stakes inside the bores. Either method is a good option. Welding before the cross and bearing caps are installed seems like a good idea, but Oshmo says they have a bunch of these in service with no problem. If I thought I would do enough miles to wear this one out, I might have gone the way you did.

    Ray
  9. fxray

    fxray Long timer

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    The Airhead has mostly been in wait mode till the swingarm and driveshaft both came back, so I have been messing with another old barn twin -- the '64 Triumph TR6R. This one shares a garage stall with my truck, so I thought I'd see if I could do some of the work with the bike in its normal parking place.

    Balanced on the centerstand, the attitude is nose down, with the front tire touching the ground. I needed to start by removing the front wheel. First try was a bottle jack under the engine, but it didn't seem stable. Next attempt was to ask my wife to sit on the pillion as a counterbalance. She told me that I was unstable. Finally I thought about a sky hook, and that worked pretty well. It only needed a little tug to make it tip back, and the garage door track was right up there over the bike. Looks like she's pulling a wheelie all by herself.

    [​IMG]

    So the wheel came off and the bike ended up like this overnight, but I could still put the truck inside the garage.

    [​IMG]

    I took my time and spooned on the new tire, cleaned up the wheel, and balanced it with my HF unit that was hecho en Chine. If you have one of these, you may notice that the supports are not in their normal position. I drilled another set of holes in the base so that I could move the supports inward and use the bike's own axle on the rollers. It is just easier and works very well. I used this balancer about six years ago to lace up the spokes in this wheel, and it worked very well for that.

    [​IMG]

    I got lucky and the same 1 oz wheel weight that had been on the wheel was still what it wanted for balance -- just had to put it in a new location:

    [​IMG]

    This little hammer worked great to tap the weight down. The hammer has one nylon insert and one brass one. The center of the head is solid steel, giving it plenty of heft, despite its small size. Both inserts are threaded and are replaceable. A machinist friend made a bunch of these last year and gave them as Christmas gifts. I have found it very handy.

    [​IMG]

    I was thinking of going to Avon Roadriders on here, but decided to stay with the vintage looking Avon Speedmasters. These get a lot of bad press, but they are actually pretty good tires. They don't like wet pavement, but this is a fair weather bike. The tires on here are exactly the same sizes, front and rear as I will need for the Airhead. I think the R90/6 will get Roadriders.

    [​IMG]

    The old tires still had some life, but next year would be 7 years from their manufacturing date code. I bought them early in the project because I wanted to get the bike into the roller stage. I have actually only ridden them 3 1/2 years. Still, I ran up 7,000 miles on them and here is a comparison old vs. new:

    [​IMG]

    There was no cupping, weather checking or other nastiness. You can see the wear bar difference.

    I figured out that, with the glacial pace at which I work, it makes sense to buy the tires as late in the project as possible. The clock is always running on tires and batteries. These new ones came from Dennis Kirk, with 1/2016 and 8/2016 date codes, so not too old.

    That said, I think it is almost time to order tires for the R90/6. Almost, but not quite yet.

    On the TR6R, I cleaned and waxed underneath the fender, where I found there was (gasp!) road dust and even some tar, and then put the front end back together. The rear was a little more involved and the bike had to come out into the middle of the floor. The truck sat outside for a few nights.

    To get the rear wheel out, I set the center stand up on a piece of 2x12 lumber for extra height. Because of the long mufflers, I pulled the exhaust system off one side to make it easier to get the wheel out. There are two rim locks on the back, which adds to the enjoyment, but I got it done without pinching a tube. The back wheel also balanced out with a single 1 oz weight. The old tire had been close enough without any added weight.

    The time killer here was that I noticed a year ago that the exhaust spigots in the cylinder head had vibrated slightly loose. This is kind of a common problem on the old Triumph's. I had sealed with some silicon last year at this time, but for the past couple of months, the engine has been popping back on the overrun, indicating an exhaust leak at the header joint. I decided I'd better do something.

    The problem with the spigots is that they run out of thread before the end of the spigot bottoms out in the bore of the cylinder head, so they won't stay tight. The cure is to remove a couple of the threads on the leading edge of the spigot so that it will bottom in its hole, and then you can tighten them down to stay.

    Yikes! We all know that if the exhaust flange nuts on an Airhead come loose and start to act like they will come off -- but then they stick again -- it is time to stop and split the nut to remove it. That's great, but you don't get that luxury on a Triumph. The spigot screws into an internal thread in the head. Mess it up, and you need to pull the head and ship it out for repair.

    At first I was playing nicey nice with it and trying to save the spigot, but then I had to escalate to where there was no going back:

    [​IMG]

    My various iplements of destruction, and I used them all:

    [​IMG]

    Then I wound up making a tool from a cheap Taiwan socket and a grade 8, 1/4-20 bolt from the local big box store:

    [​IMG]

    Adding a shot of regular oil at each end of the threads, and working the spigot back and forth for, oh, say, eternity, it finally came out. The threads are still good in the head, and I have a new pair of spigots coming:

    [​IMG]

    After I cleaned the threads in the head with a small brass brush, and then a rotary brass brush in my Dremel, wiping out the carbon etc. with paper towels. I cleaned the spigot threads on a steel wire wheel on my stand grinder. Eventually, I could thread the spigot all the way in and out with just my fingers. This was the first time these spigots have been disturbed in 52+ years. I still have to do the other one.

    I also slotted in a new rear drive chain, but broke the rules and will use the old sprockets one more time. The rear sprocket is integral with the brake drum. Changing the front sprocket requires removing most everything inside the primary chain case including the clutch. Not this year.

    The TR6R is once more a roller and is back over in its normal spot. The truck is back inside, so I did a little bit on the Airhead tonight.

    The powder coat guy calls his business Like New Parts. That's a good name. He does all the work, and what you get back is like new, and at a reasonable cost. The thing I like is that I can take in a marked-up picture showing where I want him to blast / not blast, and where to exclude the powder coat. He doesn't get offended (even if I tell him what he already knows) he just does what I ask him to do and does it very, very well. He called while I was wrestling with the TR6 spigot and said my swingarm was ready. That made a nice break from what I was doing.

    So, back to the Airhead -- remember the Airhead?

    [​IMG]

    I think the swingarm was clean inside, but I wanted to be absolutely sure there was no residual blast media inside the oil / grease areas (he uses aluminum oxide). I scrubbed all the internal areas with hot, soapy water and rinsed it a bunch of times. Then I dried it all out with a hair dryer. I cleaned the driveshaft parts in the solvent tank, dried them off, and then cleaned the taper and the threads with Brakleen. I lightly gripped the yoke end of the drive shaft with the bench vise, and torqued the nut to 150 lb. feet. Note that I did not apply any torque through the new U-joint itself. So, tomorrow, I'll see if I can find the new bearings and seals and boot and clamps and so forth that I bought for this swingarm such a long time ago, back before I realized the U-joint was bad.

    That's all for now.

    Ray
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  10. fxray

    fxray Long timer

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    It seemed to take longer this year to put the CL350 Honda and the TR6R Triumph down for the winter with their end-of-year maintenance, but I finally got it done. The last thing was to dry out the fuel system on the TR6, starting with draining the tank into a can so I can use the fuel in the snowblower. :2cry

    [​IMG]

    At least the monobloc carb is easy to drain. I gently blew some air through the lines with the bottom cap removed. Finally, I took the tank off and got all the residual fuel, finishing up with a paper towel on the end of a piece of wire. No more ethanol for a few months. This tank is not lined, and it stays perfectly clean inside. It appears to have terne plating on the inside, which has worked quite well. Next spring, she ought to be ready to rock 'n roll with just a little gas. She has a fresh oil and filter change, new tires and tubes, new drive chain, valves freshly checked, etc., etc.

    A couple days ago, I gave the bikes in the basement a quick cleanup, and squeezed them a little closer together so the TR6 could join the little crowd:

    [​IMG]

    There's still enough room to work on the R90/6, but I can't bring anything else home with me:

    [​IMG]

    When I left off with the R90/6, I was ready to put the bearings and seals into the swingarm. I did get the new bearings in O.K., but went astray with one of the seals. I didn't realize I had it slightly crooked in the bore as I was driving it in and wound up making it egg shaped. I had bought those seals clear back in January of 2015, and then one ill-advised hammer tap destroyed one of them. When I went to order another one, it had gone NLA on the microfiche, and did not show being superseded by anything else. No problem; Bob's BMW had some for me.

    Since I had to order more parts anyway, I ordered all the seals for the final drive unit. I don't think I will mess with the crown gear though. I am going to take a chance that the old seal inside will be good. I have read about variations in the gasket affecting how the gear and pinion mate up. I'd be open to advice on this. I do plan to replace the seal behind the input pinion, and I have the Cycle Works tools for that task.

    So, I finally got the swingarm and driveshaft installed.

    [​IMG]

    One thing or another slowed me down. I didn't have the brake light switch harness routed correctly so I redid that -- maybe two or three times, till I'm sure its right now. Then the torque wrench adapter worked fine on the first driveshaft bolt, but wouldn't go onto the second one at all. This is the little wrench I got from Northwoods Airheads:

    [​IMG]

    I gently ground some steel from around the nose of the wrench and it fit just fine after that. I think he erred on the side of making it stronger, but it may also be that it would fit fine on another U-joint. It just didn't like the available clearance on mine.

    I hung one shock absorber to hold the swingarm up while I was working on it.

    [​IMG]

    It may be stupid to use these shocks, but I plan to try it and see how it goes. They are sort of like 42 yr old NOS, since the first owner replaced them with air shocks almost the same week he bought this bike back in the day. I have taken the shocks apart to clean them, and they still have dampening, so I'll see. I got hung up on which way the adjuster lever was supposed to be, since I have never seen these on the bike, but I have some BMW pictures in books and I think I have it right. It points inward, toward the spokes, which seems a little scary, but sticking out the other way would foul the Krauser bags (if they ever go back on).

    The Clymer Book told me to lube the rubber bushings on the shocks with moly grease. WTF? Was there ever a time when this made any coherent sense? The center sleeve is vulcanized to the rubber bushing. That, in turn, is vulcanized to the shock loop. Maybe the /5 ones were different and the Clymer story is a carryover?

    I fitted a new boot, but re-used the old clamps, even though I have some new ones. I had blasted them and got them re-plated with the rest of the cad parts, so they match the rest of the hardware:

    [​IMG]

    Then I fooled around and got the swingarm pins centered and torqued. I got to finally use the wrench that my buddy and I made so long ago, and it worked just fine. The only reason I was using the allen wrench was to make sure the pins didn't rotate as I was torquing the locknuts. This may be overkill. I did not feel any tendency for them to turn, but it gave me peace of mind:

    [​IMG]

    Finally, as you can see in the pictures above, I installed the battery box. The only piece of black iron left in the storage tub now is the center stand, and it can't go on till the wheels are back on and the bike is off the lift.

    Actually, once the final drive is back on the bike, I could go ahead and install the wheels as they are, and make this bike a roller. That would let me put the center stand back on. I don't think I will though. It is actually more mobile while it is still on the lift, and I can work both wheels at once this way.

    So, I still need to rework the:
    • final drive -- finish cleaning; replace the seals; reinstall
    • fuel system parts -- clean and rework carburetors, petcocks, and choke lever mechanism
    • wheels -- disassemble; blast and paint the hubs; service the bearings; mount some tires, etc
    • install the center stand
    • install the exhaust
    • add oil everywhere -- mustn't forget to add oil to all the compartments
    It's slowly coming together. Most people would be done with this no later than next week. It may take me the rest of the winter.

    Cheers!

    Ray
  11. Mcgee

    Mcgee Been here awhile Supporter

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    Wow! Very nice work! I like the way you show and explain the process of putting the bike/bikes back together. Thanks again!
    bpeckm likes this.
  12. RideDualSport.com

    RideDualSport.com Zut alors!

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    Your work is impeccable! We suffer from the same disease, as evidenced by this "On the TR6R, I cleaned and waxed underneath the fender".
    Thank you, I enjoy watching and learning from you.
  13. bpeckm

    bpeckm Grin! Supporter

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    I've been away... but always a pleasure to be back and see/read your progress. You have the patience and attitude of a Zen Master.... makes me realize that I need to take deeper breaths!

    :)
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  14. David4

    David4 Long timer

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    Great work Ray, your thoroughness is amazing. :rayof
  15. fxray

    fxray Long timer

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    Thanks for all the kind remarks guys -- much appreciated.

    I've been wrestling with a dilemma. Should I send off my final drive to an expert to get it checked over, resealed, and maybe get new bearings? Should I just clean it up on the outside (maybe flush solvent through the internals) and hope for the best? Should I break it open myself? Everything I read says this last option is a terrible idea -- this is not a job for amateurs. What to do?

    As always, I started reading everything I could about it. CafeDude really caught my attention when he said this to a new airhead owner:

    That pretty well described my bike. I decided I'm going in there myself. If I cant' do it, I'll send off the pieces to some expert. Do they charge double if you attempt to fix it yourself first? :lol3

    I knew for sure I wanted to at least reseal the pinion nut, even if I went no further with the job. When I got this bike from the barn, the driveshaft had no oil, and the rear drive was overfull -- typical of a leak at the pinion seal, the threads of the pinion seal holder, or down the pinion splines. I went ahead and ordered all the seals just in case.

    Looking at some old pictures, this is my final drive before any cleaning.

    [​IMG]

    It's hard to tell for sure, but it looks like the drain under the axle had been leaking. The brake shoes were bone dry.

    [​IMG]

    There was a little oil at the base of the brake plate, but maybe it was weepage from the grease seal on the other side? The dark spot here was at the bottom of the wheel for a long time in the barn:

    [​IMG]

    Anyway, these are some relevant places to read about airhead final drives:
    ___________________________________________________

    A good summary from pokie is: HERE.

    A thread by JGT, with lots of helpful pictures (thanks, JGT -- a big help) is: HERE.

    Unfortunately, he still had some oil migration. Read about that HERE.

    Duane Ausherman's stuff is: HERE.

    And, of course, I copied off all of Snowbum's stuff and edited it so that I could read it. His original, untouched text is HERE.

    The Haynes Manual blows it off completely, saying it is beyond the scope of their book.

    The Clymer Manual makes a stab at the topic. Picture this -- you send your non-precocious five year old child to an all day training session on motorcycle repair. When he comes home, you have him write down from memory all that he had learned that day. You then try to make some sense of it. That's the level of learning you can find in Clymer.

    The BMW Factory Service Manual has very poor diagrams and is hard to follow.

    So, after all my reading, there are still some mysteries. I got tired of reading and decided to go on a voyage of discovery by taking my RDU apart. (Code for Rear Drive Unit, which I read on here several times). It was already on the work table with the brake shoes pulled off:

    [​IMG]

    First, I wanted to be able to check backlash in the ring and pinion. All I have is a magnetic base indicator. The housing is all aluminum alloy, so I started by butchering a scrap from an old bed frame to make a little bracket to hold the indicator.

    [​IMG]

    [​IMG]

    The Cycle Works pinion holder is a nice snug fit, and completely stops the pinion from turning. My indicator mounting bracket also helps with that. I found a tiny C-clamp in my toolbox that is a good fit to snug onto the splines. This ought to work O.K. to check backlash.

    While I was looking in the junk bin for that piece of angle iron, I got to thinking that it would be nice to make some kind of holding device. There was some 5" wide channel left from a long-ago project. It was a nice size. I also found some more angle iron. With some drilling, cutting and grinding, I came up with this:

    [​IMG]

    It isn't glamorous, but it works. The slotted hole accepts the shock absorber stud, as I pivot the RDU into position on my little holding device. The axle opening sits down on the small rubber pad:

    [​IMG]

    I cut the angle iron down enough to give clearance to remove the seal holder behind the nut without removing the RDU from the jig. That means I can install or remove the Cycle Works pinion holder tool, as well as their tool for the seal holder.

    [​IMG]

    Here is the pinion locking tool in place, with a couple of washers added to make up for the thickness of the angle iron bracket:

    [​IMG]

    [​IMG]

    And the tool to remove the slotted nut sleeve located behind the spline gear nut:

    [​IMG]

    So, with the RDU stable on my work table, and with the ability to check backlash when the time comes, I started thinking about a reaction bar for removing / re-torquing the pinion nut and the slotted nut seal carrier. I could clamp one leg of the channel in my vice, but the channel legs are tapered and I was afraid that would not give a secure grip. The vice doesn't open enough to put the full width of the channel in the jaws. What I had in mind was some kind of handle for the jig. Then I remembered the handle for my roll-around motorcycle jack, which has a nice, strong hook on it. I've had this lift for maybe six years and never used the handle:

    [​IMG]

    Maybe that would work:

    [​IMG]

    It did. Here are the parts laid out in order; those little chunks are what's left of the gummi-bear washer that tries to seal the splines. That soft washer (which I think I forgot to order) fits snugly into a small counterbore in the top of the spline gear. It is a bit less diameter than the steel washer:

    [​IMG]

    The next trick is to remove the slotted nut seal holder. The Cycle Works tool is simply a large nut with precision width lugs screwed into it on four sides to fit the slots in the seal holder. The 1/2" drive socket that fits the nut is also from Cycle Works. It is sold separately from the rest of the tool, so if you already have a 41 mm socket, you won't need to buy it. I've lived my whole life never needing a socket bigger than 36 mm that I used once for a VW (and again finally on this R90), so I had to buy one.

    Everything I've read says to heat the housing before you attempt to remove the slotted nut. I don't like to heat a case or a housing with a torch, because I don't like the idea of localized heat. I don't like a heat gun for this either, and it would take too long anyway, even if it did work. I would rather put the whole thing into the oven on a cookie sheet. Before I do that, though, I want to clean out all the oil from the housing. That means the crown cover needs to come off next.

    [​IMG]

    Flipping the fixture up on its side, it was easy to remove the 10 nuts and wave washers in a criss-cross pattern. Next I need a couple of M5x.8mm jacking bolts to break loose the crown cover. I don't have those handy, so its off to Ace Hardware I go. While I am there, I'll pick up some new wave washers.

    More to follow as I get to it . . .

    Ray
  16. JGT

    JGT Been here awhile Supporter

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    Good start on all that and nice jigs, etc!

    I fixed my final drive oil migration problem last winter (had to take the pinion gear or whatever it is called out again). Basically, where ever Snowbum or Duane or anyone calls for using "goop" to seal up the threads, spline grooves, etc. don't use Hylomar. Use Permatex Gear-Oil Resistant RTV. I used Hylomar the first time and it is oil soluble so it did not work. The Permatex stuff did the trick and the leaking is gone now.

    Best of luck!
    Bunt227 likes this.
  17. fxray

    fxray Long timer

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    ^^^ Thanks, JGT. I read that and referenced your thread in here. Some people told you that Hylomar should work, but I will go with your experience. I appreciate all the pictures you took. It helped me understand what the books were talking about.
  18. fxray

    fxray Long timer

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    Location:
    Illinois, USA
    With the M5x.8 pusher bolts handy, I ran them into the two threaded holes in the crown gear cover and and lightly snugged them to see what happened. Luckily before I did any harm, I remembered I still needed to remove the brake lever and cam shaft. I marked the end of the serrated shaft with a dab of paint next to the slit in the lever, so I can get it back in the same position. This '74 brake cam shaft has a felt seal that looked better than expected, but no O-rings. I guess those came along later.

    [​IMG]

    I put the unit back onto the holding fixture and tightened the pusher bolts, seen here at about the 2:00 and 8:00 o'clock positions. The crown cover lifted with no drama:

    [​IMG]

    Here's the cover flipped upside down, with the ring gear still in place. The four equally spaced holes can be used to drift the bearing off the other side if necessary. I'm hoping and planning not to do that. Most of the gasket stayed on the housing:

    [​IMG]

    Looking into the housing, I see a little dab of oil that didn't all quite drain out. It looks clean except for one place where a patch of sludge has settled out. Measuring the gasket thickness in several spots comes up .0185" (.470mm), while the new one I just bought is .0115" (.292mm). I guess that will be something to deal with later.

    You can see the pinion teeth here, and even I won't get too mixed up. The crown cover can only go back on in one position due to the brake cam shaft opening.

    [​IMG]

    Here's a closer look at the sludge patch, and the axle sleeve which is uniformly coated with surface rust. Both these issues are the result of sitting still for 18+ years with no oil changes. Maybe it is good to clean things up inside here, but the seals that I've seen so far are still soft and supple.

    [​IMG]

    The teeth all look good to me, with no apparent pits, galling or chips. Of course those may show up after cleanup. Meanwhile, you can see the wear pattern positioned correctly (my opinion) on the flanks of the teeth. The pattern doesn't show very well in the picture for the pinion teeth, but is easier to see on both sides of the ring gear:

    [​IMG]

    [​IMG]

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    Next steps will be to do a lot of careful cleaning and gasket removal and then use some heat to do some more disassembly.

    Ray
    BoxerD likes this.
  19. fxray

    fxray Long timer

    Joined:
    Feb 22, 2014
    Oddometer:
    1,438
    Location:
    Illinois, USA
    Reading Snowbum's articles on Airhead final drive repair, I found where he said , "You may find the hardest part is cleaning off the old gasket."

    After spending much of yesterday cleaning the various final drive parts, with most of that time devoted to the gasket surfaces, I agree completely. I think I did finally get them cleaned up with no harm. The holding fixture was a great help with this, keeping the housing flat, level, and stationary while I attacked that nasty gasket.

    Here's a little update:

    [​IMG]

    I have not yet disassembled the ring gear from the cover, as shown above, but I have gotten the final drive housing itself torn down as far as I plan to. As you can see, the axle bush and needle bearing are gone from the housing. More on that in a bit.

    The last part of the cleanup was in the parts washer, with mineral spirits. Disassembly calls for heat in the oven, so I dried the parts thoroughly by blowing them off and wiping with paper towels.

    The first part I wanted to remove was the threaded ring that holds the pinion shaft seal. I had read that I only needed to heat the housing to 100°C (212°F) to unscrew the ring, and that did work fine. I put the hub, complete with the fixture I had made for it, on an old cookie sheet and put all that into a cold oven. I set the oven for 210°, let it come up to heat, and then sit at temperature for a few minutes. There was only a little smell coming from the stove, but when I opened the door, out came a small cloud of pretty smelly white smoke (no fire though) and the entire housing was covered with drops of sweat, the mineral spirits having cooked up out of the pores in the surface. So much for blowing off with compressed air, and wiping down with paper towels!

    Anyway, here are the parts laid out in the order in which they will go back onto the pinion shaft, left to right on the top row, and right to left in the bottom row. I haven't removed the old seal from the slotted nut yet:

    [​IMG]

    Next I wanted to remove the ring gear needle bearing and the axle bush. The idea is that, with the housing upside down, you can heat it till the bearing falls out. Trying to be conservative with how much heat I used, I wiped the final drive housing down again and put it back into the oven, which I kicked up to 250°F. That didn't work. Neither did 300°F.

    I kicked the temperature up to 350°F and let it soak at that temperature for a few minutes. Then, wearing some leather gloves, I took the housing out to the garage, held it level about five inches over a solid wood surface, and smacked it down as hard as I could. The second time I smacked it down, the bearing came almost all the way out. One more reheat and one more smackdown, and out it came.

    Once more in the oven for a few minutes at 350°F, and I used the axle to lightly drift out the bush. Here are the pieces removed:

    [​IMG]

    The bush has some rust to be removed. It isn't plated, but it would normally have oil all over it to prevent rust. Sitting still for all these years hasn't helped it any. Also the top of the bearing looks bluish in the picture, as if it had been hot. That is just the lighting. It is actually bright and shiny chrome or chrome alloy steel.

    [​IMG]

    With the parts disassembled to this point, I could get a clearer notion of how those two drain holes in the final drive housing were set up to handle possible leakage. The one under the axle is just a short, direct passage:

    [​IMG]

    Poking the seal pick into that drain hole, and looking on the other side, the other end of the passage is between the right-most seal and the press-fit end of the bush. This seal is the deepest one -- the one that is perhaps the hardest to access. Oil getting past the seal will drain out near the axle.

    [​IMG]

    The seal in the picture above is slightly mangled because I tried to collapse the side of it with a screwdriver. I also tried to grab the edge of it with needle-nose pliers and pull it out. That didn't work, so I will use a blind seal puller. I read on here that JGT had success using a modified version of the Cycle Works swingarm bearing and seal puller. I have one of those, so I'll give that a try.

    The other drain hole is clear at the bottom, near the actual final drive drain plug opening:

    [​IMG]

    Probing this drain and looking on the other side, we see that it follows up a rib in the casting and intersects at 90° with another hole. The seal pick was too fat to go any further into the drain so a piece of wire would have been better in this picture. Anyway the drain comes out in that opening directly above the seal pick shown here:

    [​IMG]

    Note that the drain port goes to the gasket surface. There is a corresponding hole in the gasket and the crown cover, which is the mating part:

    [​IMG]

    The hole in the crown cover passes at an angle upwards and to the left, toward the splines. In normal operation, this passage would be oriented up / down, not sideways as shown here. Oil that escapes the large seal in the crown cover would run down out of this drain -- unless, that is, the drain outlet gets plugged up. Then the oil would puddle over and run into your brake shoe area. That would not be healthy, so the recommendation is to give that drain a periodic shot of compressed air:

    [​IMG]

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    Next steps will be to extract that innermost seal, and then to heat and separate the crown cover from the ring gear and shims.

    Ray
    BoxerD and Jim K in PA like this.
  20. fxray

    fxray Long timer

    Joined:
    Feb 22, 2014
    Oddometer:
    1,438
    Location:
    Illinois, USA
    Thanks to a tip by JGT, that innermost seal is out of the drive housing. The Cycle Works swingarm bearing puller did the job. They use a short 7/16" bolt to spread the "fingers" inside the seal or bearing race being removed. The one that comes with the tool measures about 16mm across flats. I found a 7/16" nut that measures 17mm across flats and that was enough to grab this seal. It is just that much bigger than the swingarm seals and bearings for which the tool was designed.

    [​IMG]

    JGT made a different upper plate for his puller, and that is the right thing to do. The sleeve that comes with the tool is too small in its inside diameter to allow the seal to pull up inside it. But, I used it anyway -- just a smidge off center:

    [​IMG]

    That pulled up one edge of the seal so that I could grab it, give it a twist, and pull it out with a small pair of pliers. Once the puller budged it loose, it was easy to extract. Here, I just stuck the seal back onto the puller fingers to show how it works. That white stuff is white lithium grease which makes the puller work so much easier.

    [​IMG]

    So, onward to the pinion seal that fits inside that threaded ring. I found a couple of sockets that fit there quite well. On the left is a 1 3/8" socket that I vaguely remember as a Harley tool. On the right is the new 41mm socket that I just got from Cycle Works. Here we are looking at the backside of the seal (the side that faces inside the drive unit):

    [​IMG]

    With the 1 3/8" socket on the back of the seal, a couple taps with my ball-pein hammer knocked it right out. Using that hammer, it occurred to me that it is about the same vintage as this old motorcycle. I bought the hammer in 8/73 when I started a job in a machine shop. The bike was built less than a year later, in 6/74.

    [​IMG]

    Then I flipped the ring over and used the 41mm socket to tap it back in -- a test run to see if it works O.K. before I fool around with a new seal:

    [​IMG]

    Worked just fine!

    [​IMG]

    Then it was time to fab up yet another special tool -- a seal protector to slide over those splines on the ring gear so that I could remove the crown cover. I actually had to go out and buy a couple cans of soda from the gas station. The days of soda and beer cans in the recycle bin are long gone around here. I bought two cans, just in case. I drank one and let my wife drink the other one, after I cautioned her not to damage the can in the process! :lol3

    First, some prep work. I drank the soda, and then removed the bottom of the can. It needed to be cut off straight, so I set the can on a flat surface, held a sharpie marker against the can, and gave it a spin. Those are not my cigarettes either. I'm so reformed its ridiculous:

    [​IMG]

    The aluminum can is so thin that it is easy to cut along the line with scissors (leave no burrs on the edge!). Thin is what you need for this job. The can has to slide down over the splines and slip under the lip seal without cutting the seal. In my case, it wouldn't matter because I am replacing the seal. However, I wanted to see if I could remove the cover without damaging the seal -- just for future reference. The can could not fit more perfectly if it had been made for this purpose.

    [​IMG]

    I put this into the oven on my old cookie sheet and set the control for 325°F. This worked fine, but it did sweat some more mineral spirits out of the metal, just like with the housing I did earlier. After one time in the oven, the parts are all dried out and they quit making a mess.

    I let the cover heat soak at temperature for a few minutes, then grabbed it with my leather gloves and went to the garage. I set the assembly down with the can on the bottom, grabbed the edges of the cover, and it easily gave up its press fit on the roller bearing to slide right down. You can see the sweat beads of mineral spirits here.

    [​IMG]

    The reason the cover seems to be levitating here is because the lip seal inside the crown cover is a snug fit on the O.D. of the soda can. Better to slide the seal on the smooth outside surface of the can than on the edges of the splines!

    Side story: It's funny how history repeats itself. I first used this piece of apple tree (it isn't from the trunk, it's from one of the tree limbs) way back 48 years ago, in 1968. My Dad was helping me repair a bearing in the rear end (final drive) on my 1963 Pontiac Tempest convertible. The bearing had seized and locked up solid. The gear then began spinning inside the now stationary inner race of the bearing. That inner race was supposed to be a thermal press fit on the ring gear -- the same set up as the bearing and gear we have here.

    We saved that gear. My Dad took it in to where he worked as a mechanical engineer and got the machine shop to grind the gear's bearing diameter undersize till it cleaned up. Then they built just that surface back up to size by plating it with hard chrome. They plated it till it would make a couple thousandth's interference fit with the new bearing. Aside from buying the new bearing, it was all free -- just a little side job.

    He showed me how to put the gear in the freezer overnight and heat the bearing in the oven. We set the cold ring gear on this very same old piece of apple tree and he held it steady while I drove the bearing on. He told me, "Hurry, but don't mess up -- you only get one chance with this!"

    Here's the tree when it was still making apples. It sat at the very back of the yard, and the building in the background is the back of the Studebaker new car dealership. Even that '62 Chevy station wagon in the gravel lot would be worth some money if it were around today.

    [​IMG]

    This chunk of tree limb has been used for stuff like this for so many years now that I just can't throw it away. I almost split it and had a ceremonial burning to get it out of the garage a couple years ago, but somehow I couldn't bring myself to do it. I still remember the applesauce my Mom used to make from that tree's produce. Delicious!:

    [​IMG]

    And here is the car that worked just fine after I got it back together. I've been doing this stuff for a long time, eh? Note the '56 Chevy in the neighbor's driveway.

    [​IMG]

    Anyway, returning from the stroll down memory lane and back to the BMW R90/6, here we have the crown cover removed, and the can is still slipped over the splines. Note that it fits clear down over the turn diameter where the seal will run, making this can a good installation sleeve:

    [​IMG]

    It is amazing how perfectly sized the can is for this purpose. I will use it again when I put things back together. You could wrap the splines with tape, but this is much easier and less messy. Plus, the can has a nice, smooth lead-in taper for sliding the new seal into place. That should make it go onto the seal surface of the gear without rolling the lip of the seal. Perfect!

    [​IMG]

    Here are the numbers from my ring gear, visible now that the crown cover is off. Somebody from West Germany scribed those on there before Ronald Reagan and Mr. Gorbachev tore down the Berlin Wall.

    You can also see the spline wear at the base of the teeth. Not bad at all, really:

    [​IMG]

    [​IMG]

    I'll deal with those numbers in the next update. Right now, I found that I do have the little gummi-bear seal for the input shaft which I thought I had neglected to order. However, I do not have the lip seal that goes deep inside the housing -- the one that I was removing at the start of this post. I was sure I had ordered it. Don't you just love buying a $7 part and paying $10 shipping? :arg

    See you next time.

    Ray
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