My rear brake cylinder got ripped out.

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by adrenalin-junkie, Mar 19, 2006.

  1. adrenalin-junkie

    adrenalin-junkie Been here awhile

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    I am so damn pissed off at myself . Myself and 6 other friends went for a ride in the woods in North Carolina today. I highsided my bike at about 15 mph . My front end washed out after I hit some mud underneath some leaves , which sent me into a spin . I slipped off the side and gave it a handfull of throttle . Firstly it got traction , got it back under control and spun out the opposite way . It highsided me and the rear brake lever got stuck somewhere , and the cylinder got ripped out . We manage to save all the parts . So I had a 90 minute ride back to SC from NC in the sweeps with only front brakes .

    So my question is . What do I need to look out for before assembling the rear brake assembly.I know someone else , must have had the same problem.
    #1
  2. motophil

    motophil Paint it black!

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    Can't help you with the assembling since it hasn't happend to me yet, but the problem is so common that the someone in the german KTM 950 forum (forum.lc8.info) built an adjustable upper stop for the brake lever that fits into the hole for the rear axle.

    As far as I recall for reassembling you don't need to touch the hydraulics of the brake, just refit the pushrod with a new snap ring.

    - Philip
    #2
  3. utahrpm

    utahrpm Been here awhile

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    #3
  4. DPRider

    DPRider Been here awhile

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    I went down on one of my first rides with my new 05.5 last February (2005). I was on a fire road that still had patches of ice in the shaded areas (that I didn't discover until it was too late). My brake lever got pushed halfway up the clutch cover.

    The only caveat is that the internal snap ring that retains the pushrod is not the usual type of snap ring. It is a special type with "increased abutments" built to DIN 984 standards and no one here in Canada ever heard of them. I had to use a left over shim from a WP fork and a standard snap ring. If I can find the proper ring I will change things back to where they should be.
    #4
  5. Autostream

    Autostream Long timer

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    Some days one just needs a tangent to go on...

    After reading this thread and remembering it mentioned before I thought I would rustle something up...

    Started off with a 60mm off cut of Delrin and turned one end of it down to be a slight interference fit into the end of the swing arm mount. Then I bored out the centre a little so it could crush slightly allowing me to pop it in with a soft faced hammer.

    I next fashioned the original outer diamater of the remaining unturned part to provide a stopper for the lever and fit within the contours of the frame.

    All up the MK1 took 15 minutes to think up and make and the Mk2 final version you see about the same...just wish I had some black Delrin in the right size...

    Once you have settled on a consistent height for your rear brake this is a pretty quick fix that weighs almost nothing. If I ever need to remove it I just need to use a rod down the swing arm pivot to punch it back out.

    may not protect it from a major impact, but where do you start and stop with these things?
    [​IMG]
    #5
  6. Joey

    Joey READZ

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    What a brilliant idea, just wish I had the tools to copy it. You should be knocking these things up and selling them on here Autostream. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:eek:ffice:eek:ffice" /><o:p></o:p>
    You may be able to answer me a question here, not being very mechanically minded beyond oil changes and break pads. I recently noticed my rear break was seeping fluid. I stripped it down from the back of the leaver, cleaned everything up and noticed inside the rubber sleeve (see your pic) there was a washer and a circlip that just seemed to be floating around having no purpose for being there. After checking my parts manual, yes they are shown as parts but what do they do and where do they sit? The circlip seems to only sit in the bottom of the rubber sleeve with the washer above it?

    Thanks<o:p></o:p>
    #6
  7. Autostream

    Autostream Long timer

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    Sounds like the circlip and washer that holds the brake cylinder piston in place. If they have either not been fitted correctly, or more likely have been pulled out by falling off & forcing the brake pedal up, this would allow the piston to come down too far and leak (or worst case fall out).

    There is nothing more than this clip & washer to hold it all together as there is no stop on the pedal as such, unless you make something up.

    Sounds like you need to get some circlip pliers, push the piston back up, push in the wahser and refit the circlip in the groove. Mine has never come apart so I cannot comment beyond this theory....I made my stop as a preventative thing.

    The problem with my version is that it is a personal thing, depending on the height you like your brake pedal as the length of the stop is made to suit that height & is not adjustable.

    Someone like Adventure workshop could probably easily make a commercially available adjustable version. I do not have time.
    #7
  8. adrenalin-junkie

    adrenalin-junkie Been here awhile

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    I have been tinkering with the same idea . So now that answers my question . What was missing from my rear cylinder reservoir ? I suspected it to have been a snapring .

    I said to myself today " Self , you have to stop behaving like that , and preserve your bike ". But this damn bike is way too much fun to ride slow.
    #8
  9. wsmc99

    wsmc99 Been here awhile

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    Autostream,
    Is there a picture of this contraption you've made?

    Thanks,
    Tony
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  10. TipOver

    TipOver Been here awhile

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    Tony, Look at Autostream's 3-25-2006 comment. It includes a photo, the doo-dad referenced is the white oval above the brake lever. I guess Delrin is a high tech plastic? :eek1
    #10
  11. wsmc99

    wsmc99 Been here awhile

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    It's not coming up in my view at all. :huh
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  12. adrenalin-junkie

    adrenalin-junkie Been here awhile

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    After getting my ducks in a row , I managed to put my rear brake cylinder together. All it needed was the snap ring , and it was done . Luckily nothing was damaged . To bleed the brakes took me about 10 minutes , and I was on my way .

    Next thing on the things to do list , is definitely the Brake stop lever.
    #12
  13. Autostream

    Autostream Long timer

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    It is basically what you see in the photo. All you can't see is the part that is a tight fit into the swingarm recess that goes all the way down in as far as it can...about 20mm

    I don't have any measurements as I made none, just made it up by eye more or less. Basically just fashioned up by hand with a linisher after the main core was turned to size in a lathe.

    If you can't see the picture try... http://www.seahawk.com.au/ADV/brakestop.jpg

    Delrin = really tough plastic / acetal resin / engineering grade plastic http://heritage.dupont.com/floater/fl_delrin/floater.shtml
    #13
  14. Autostream

    Autostream Long timer

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    I was looking at what parts I could use as bling for my 950 ADV of of a 950 SE and noticed the SE has a brake pedal stop to prevent it being pushed up and pulling the circlip & internals out of the rear brake master cyclinder.

    After scrounging around to find one of the SE Bike lierature packs that actually had the parts books in it I found that this part is actually 58413048000 Brake Stop LC4 with a US list of $3.91.

    You also need a countersunk head screw and nut (didn't get the part number but aftermarket would do it) and you need to drill a small hole in the flat gusset part of the frame above the brake pedal.

    The idea is really simple, it is just a round peice of metal with the mounting screw drilled off centre so that you can adjjust it to suit pedal height.

    Find a LC4 or 950 SE to look at and see how it's done as it is easier than the fix I created above.
    #14
  15. Gert

    Gert Made in Denmark

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    This is what it looks like on the SE:

    Attached Files:

    #15