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  1. #1
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    Stuck Rebound Knob

    I bought a 2007 Prophet 6 off someone a few days ago. He built it off the frame, and it's quite a nice piece of work with a ton of carbon fiber parts.

    I reset the needle bearings just now on the lefty max 140mm, and gained a good inch of travel. I think I might have tightened the rebound knob a little bit too much during this process though, as it now only spins if I use pliers, but doesn't spin the plastic base, just spins inside of it. It was working right before I reset the bearings, so it's definitely something I did wrong. Just so we're clear, I'm talking about this knob (clicky!).

    I sprayed a little bit of wd-40 onto it in hopes it will unstick it, but I don't trust the stuff nearly as far as I can throw it. Short of drilling a few holes where the plastic and the knob meet and using screws to attach and take the assembly out, does anyone have any ideas on how to fix this?

    TL;DR: Probable overtightened rebound knob, need help.

    Thanks in advance

  2. #2
    All Lefty's, all the time Moderator
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    Best chance you have is to remove the preload tube from the upper damper shaft.

    Get back to where you could do a reset.

    Need a 19 mm and a 9 mm box wrench. Loosen the preload rings to the point that there's slop between them and the coil. At the end of the threads (inside the coil), the damper shaft threads in, you'll see a 9 mm flat.

    19 under the split ring seat up top, and unscrew.

    Same procedure as a spring swap.

    If taking that pressure of doesn't allow you to unscrew it, you broke the bond between the red aluminum cap, and the nylon body it sits on. Crush with pliers and forcibly remove, shop for new knob.....
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  3. #3
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    Didn't feel like going out to get a 9mm wrench so I just ground it out of a bar of steel haha. Worked a treat.

    Unless I'm going crazy, it is an air sprung preload, going by the Schrader valve at the bottom. Eventually I'll work up the nerve to take the whole thing apart and see for myself how it works.

    I managed to get the damper tube off, but that didn't loosen the rebound knob at all. I ended up doing what I said I might, and drilled two small holes at opposite ends of the nylon insert and used pins to unscrew it. Saved the two ball bearings and the spring.

    The threads are kind of screwed up from drilling, but I've worked with worse. A little x-acto knife cleaning should get it in working order.

    The knob was spinning on the insert though, so it's probably broken. Is the red knob supposed to be permanently attached to the nylon insert? If so, how? I hope I may be able to salvage it somehow, but I don't know how it's attached, and I don't want to break it I the process of finding out.

    EDIT: After cleaning up the threads a bit, I can now screw and unscrew the knob/nylon insert in the damper tube by hand. I still don't know why I had so much trouble unscrewing the darn thing, but after getting it out and cleaning the threads, it's looking pretty good. I'll put it back together with some grease and leave it be, and if the knob starts to spin in the insert again, I'll figure out a way to attach it in a way it'll never come off again, haha.

    Thanks for the tip about taking off the damper tube. That made my life so much easier trying to fix this. I'm still curious as to how the red knob connects to the nylon insert though, if you know. If I need to fix this again, that'll make me feel better about not screwing up.
    Last edited by Masterjuggler; 09-18-2015 at 08:00 PM.

  4. #4
    All Lefty's, all the time Moderator
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    It's either a snap fit or glued.

    Don't know for sure, doesn't matter, they all work, till they get stuck, then forced, then that "bond" breaks, and they never turn the core again.

    It is coil sprung, you just have an SPV model which offers air tuning of the platform function, which makes the fork resistant to compression. See that big spring when you were taking everything apart? Yeah, that's your spring....



    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  5. #5
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    Thanks for mentioning that it's the SPV model. I probably would never have figured it out otherwise. Now that I looked through the manual for it, I see how to adjust everything, and the size of the main spring makes a little more sense now, lol. I just ordered a lighter spring for it, because I'm much lighter than the previous owner.

    Actually, this lefty was rebuilt by you guys sometime last year, going by the mendon cycle smith sticker on it. I just cleaned the air filter and under the boot, and it works great. Thanks for the help so far.

  6. #6
    Just a flesh wound
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    Swap it over to the PBR Air. Much better.
    My name is Chris and I ride a Prophet 650b with a Lefty.

  7. #7
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    I'll probably do that eventually, but my limiting factor right now is my budget. I still have yet to sell my old bike, and even then.

    How would I go about doing that? After a bit of research, I see the original thread about it, but nothing on exactly what parts to get or how to do it, unless I missed it. I don't actually know how much it would cost, I'm just assuming it's not a cheap thing.

  8. #8
    All Lefty's, all the time Moderator
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    $280 in parts, but not typically a DIY job.
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

  9. #9
    Just a flesh wound
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    Totally understand the budget. The upgrade is a game changer, so keep it in mind when you are thinking of an upgrade.
    My name is Chris and I ride a Prophet 650b with a Lefty.

  10. #10
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    I just read through the entire "Good news for older Lefty owners!" thread. It'll definitely be my next upgrade once it's in my budget (half a year? Hopefully...).

    Even if I did have the budget, I just switched to this bike from the Trek 3500. It's already a night and day difference, and the trek feels like a toy now. I want to get used to this so I'll be able to tell the difference between the current SPV and the PBR. I'm trying hard not to get the upgrade bug, but it seems to happen to every hobby I pick up lol.

    Mendon, expect to get this fork back again at some point, this time for the upgrade. Has cannondale been coming out with new PBR versions every year, or did it stop at 2012/13? I saw that the only differences between the 11/12 versions were bug fixes. Basically, do you have any info about the conversion over the past few years?

  11. #11
    All Lefty's, all the time Moderator
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    It really hasn't changed appreciably in a bunch of years.

    One modest tweak of removing a shim in the stack was about it, otherwise, same stuff, different day....
    This is a Pugs not some carbon wannabee pretzel wagon!!

    - FrostyStruthers



    www.mendoncyclesmith.com

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