12GS Rear Disk Flange Cracks?

Discussion in 'GS Boxers' started by AJB1, Nov 29, 2007.

  1. hancockbs

    hancockbs Auburn Alumni

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    Using the link that was provided, I got the old flange off with no problem. Now to get a new one and install it. Appreciate the help.

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  2. Mudcat

    Mudcat Unregistered

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    :thumb
    Wow, you are quick.
    My flange went on easer then it came off.
  3. Maverick75

    Maverick75 Rat

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    My replacement flange (steel) was a pain to get on. I heated to 130c and it went on about 2mm then froze, I tapped it off and heated to 250c and it went most of the way on then froze. The next 1/2 hour was spent with packets of ice sitting in the final drive hole whilst reheating the flange with an oxy and tapping it 1-2mm at a time. You don't want to hammer too hard on the drive because next thing you know the bearings will shit the bed (I bet).

    I used the old flange as a drift to tap the new one on with a rawhide hammer. A press or similar would be much easier.
  4. Mudcat

    Mudcat Unregistered

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    Your steel flange went on like my old aluminum one came off.
  5. rdcyclist

    rdcyclist Long timer

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    Ummm...this is a bad idea. Pounding on bearings axially (what Mr Maverick did) with a hammer of any type is a very good way to ruin them. A bearing press is better, but the best way is to throw the FD into the freezer and the new steel flange into the oven (make sure the spousal unit is either not at home or approves of this use) at 350-400F. Have the bench cleared and ready to accept the FD and quickly slide the two together. The less axial loading, the better.

    If you do get the flange part way on and you gotta pound (no press availability) make absolutely sure the opposite end of the axle is firmly loaded against the bench to minimize any undesirable axial bearing shock. Yeah, I know, this is a big ass final drive and the bearings should be able to take it. I also know that I've seen plenty of f*cked up bearings from hammer mechanics, myself included in that description...:bluduh
  6. Maverick75

    Maverick75 Rat

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    Yeah rdcyclist, trust me, the hammering was very light (which is why I wrote 'tapping'). It took a considerable amount of heat to allow the tapping to be light though. I too know the consequences of Brinelling on bearing races. The loads applied by me wouldn't have been any greater than those experienced in service.

    But I agree, to anyone who hasn't experienced bearing failure from heavy handedness, use a press. :1drink
  7. nanotech9

    nanotech9 ** Slidewayz **

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    why not reverse the puller process?

    put the axle stop on the opposite side of the axle (or something that you can put a long bolt through) and then use the puller to press the new flange in place.



    like this:

    Puller, Flange, bolt through axle, aluminum part that rests against axle on right side w/ through hole, bolt head.

    Just like a poor mans bearing press when you're installing new swingarm bearings on your dirtbike :)

    No pressure on final drive.
  8. nanotech9

    nanotech9 ** Slidewayz **

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    the loads placed are with the bearing at rest. tapping over and over in the same or nearly the same place will be more likely to out-of-round the bearings as opposed to a side force while they're spinning.
  9. Maverick75

    Maverick75 Rat

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    Only if you exceed the yield point of the bearing material. Trust me I didn't. If I did the bearings would brinel with the bike sitting on the side stand (and fail when I sat on it). :rofl
    We could get into impulse calcs but I guess I'll just wait for my drive to shit the bed. It should take about 1000km or so (so middle of last month) :wink:.

    *edit* There is a world of difference between 'gently' tapping a bearing with a soft hammer and hammering the shit out of it with a steel one. Go grab an old bearing race and a ball (hell, even a centre punch) and see how difficult it is to mark the race with either using a soft hammer. Now try it with a steel one.

    I've replaced a number of bearings using 'gentle persuasion' and although not ideal (mainly because it takes so long) I haven't had any appreciable loss in service life by doing so. Yes, arm restraint is required but I guess that's what seperates good mechanics from gorillas.
  10. Mudcat

    Mudcat Unregistered

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    Did you get the new flange on?
  11. hancockbs

    hancockbs Auburn Alumni

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    BMW seems to have gone to a third version of this flange. It now comes in two parts; the flange, which is about 60% as thick as the original and a spacer ring, which is not heat fitted. The flange appears to be steel now as well.

    <a href="http://www.flickr.com/photos/bs_hancock/7571824814/" title="photo by BS_Hancock, on Flickr"><img src="http://farm8.staticflickr.com/7134/7571824814_65bd3ebb16.jpg" width="500" height="375" alt="photo"></a>

    <a href="http://www.flickr.com/photos/bs_hancock/7571825352/" title="photo by BS_Hancock, on Flickr"><img src="http://farm9.staticflickr.com/8421/7571825352_a98c7c4ae9.jpg" width="500" height="375" alt="photo"></a>

    I received it from Countryside BMW on Friday. Total for the two parts, plus five rotor bolts and shipping was a bit less than $300. I installed it yesterday. It was very hard to get on. I used a lot of ice to keep the axle cool while continually heating the flange and it went on a tiny bit at a time. I am concerned about torque values now. I don't know if they are different for the new flange design. If I can get a good answer, I will post it.

    It was also pointed out by a sharp eyed person that the wheel holes on the flange might be cracked. After cleaning it up a bit, I found that all five holes are cracked. I guess losing the rotor at low speed is probably the BEST thing that could have happened here.
  12. Emoto

    Emoto Sure, why not?

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    If that is the same p/n that was put on my bike last year, it is not the third version, if the following can be believed: My dealer has a contact inside BMWNA who he calls and speaks with about stuff sort of unofficially. Last year, the steel one with flange came out in Germany first and then gradually tickled into this country. Anyhow, the guy told him that the AL flange being sold just before the steel one came out was already the fourth version of the part.

    P.S. Thanks for posting pics of the two together! Very nice job.
  13. Mudcat

    Mudcat Unregistered

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    You know, I think it’s like the 5th version
    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p> </o:p>
    When I replaced my flange the steel one was not available in the <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:eek:ffice:smarttags" /><st1:country-region><st1:place>US</st1:place></st1:country-region>, I was secretly happy about that. I thought I might have trouble installing the steal flange.
    <o:p> </o:p>
    My GS is a 05 with a servo. It sulfured from premature rear pad wear. I always thought the problem was servo related. Since I changed my flange that issue has disappeared, I also change the rear rotor too.
  14. Emoto

    Emoto Sure, why not?

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    Interesting. I also have an '05 with whizzy brakes. The first set of rear pads wore out VERY quickly, but when I replaced them, I went with the other compound choice (sorry, can't remember name) and those have lasted better, although still not what I would have if the brakes weren't linked.
  15. Mudcat

    Mudcat Unregistered

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    I have always ignored the linkage; I use the brakes as if they were conventional.
    My OEM pads needed to be replaced at 6k with EBC HH pads the pads would go 15 thousand.
    Since I changed the flange and replaced the rotor with an EBC rotor. My rear brake has never worked better, it is progressive and strong, and I am not getting much wear on the pads.
  16. Emoto

    Emoto Sure, why not?

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    I ignore the linkage, too, but on other past bikes, I almost never used the rear brake at all, so the pads went almost forever.

    I should check my maint log for when I've replaced rears, but the first set went at a short distance like yours did. Currently running a set of Carbon Lorraine pads in the rear.
  17. marchyman

    marchyman DR and GS

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    The set of rear pads that came with my '05 GS were worn at 18K miles. When changing the pads I cleaned and lubed the caliper. The pins were quite dry. Since then I've not worn out rear pads. Instead I've had to change them because I dropped pads in gear oil or changed rotors (which called for new pads).
  18. Mudcat

    Mudcat Unregistered

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    After my first set of pads wore so quickly I lubed the rear caliper per johnjen&#8217;s directions in Wisdom. It helped marginally. My second set of pads were Galfer, OEM eqivalent, and they went out at 7 or 8 k
    I always lubed the pins when I change pads but I have never taken the caliper apart again
    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    Steptoe, has a possible fix for dragging rear brake pad on a servo equipped GS. He said it only worked some of the time, below is a link to the thread. I never got around to trying it.:dunno And it doesn't appear I need to now.
    http://www.advrider.com/forums/showthread.php?p=15017070&posted=1#post15017070<o:p></o:p>
  19. Emoto

    Emoto Sure, why not?

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    I just make sure my pins are clean. What are you guys using for lube on them?
  20. Mudcat

    Mudcat Unregistered

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    I use neverseize