Page 1 of 2 1 2 LastLast
Results 1 to 25 of 30

Thread: RS Reba popped

  1. #1
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    60

    RS Reba popped

    On my ride this morning I came to the bottom of a hill and heard a loud popping sound. I got off my bike and looked around but wasn't able to find anything wrong. So I got back on and finished my ride.
    As soon as I got back to the car I looked down and noticed that the top fork bushing/ring had popped up, exposing the foam ring below. I attached a picture of it below.

    Has anyone else had this happen before? I supposed I can just clean it out, put some more lube on the foam ring and pop it back into place. But I was wondering if there was something more permanent I can do, or if it is a sign that something else is wrong also.
    Attached Thumbnails Attached Thumbnails RS Reba popped-dsc06805.jpg  


  2. #2
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,884
    I have seen this happen before. Why ? The fork was leaking air past the lower air spring seal (o-ring) and pressurized the lowers - enough pressure and pop goes the seal. If the Reba is a Dual Air U-turn you can also lose pressure from the top (positive) chamber which will pressurize the lowers.

  3. #3
    mtbr member
    Reputation: Kiwiplague's Avatar
    Join Date
    Jul 2011
    Posts
    1,034
    Had this happen on my Sektor last year, and my brother had it happen to his Rev. Seems to be a common Rockshox issue when the seals in the neg air wear out.
    I don't crash, I just have slightly uncontrolled dismounts!

  4. #4
    mtbr member
    Reputation:
    Join Date
    May 2012
    Posts
    7
    Hmmm.

  5. #5
    MTB B'dos
    Reputation: LyNx's Avatar
    Join Date
    Oct 2004
    Posts
    17,222
    Easy fix...... do a service, remove the crappy RS seals, replace with Enduro seals.
    One day your life will flash before your eyes, will it be worth watching??
    MTB Barbados
    My MTB vids

  6. #6
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    60
    What is the name of the seals that I should look into replacing? And where are they found? I have take apart my fork a few times, mainly to take out travel spacers, but I am having a hard time remembering where the seals for the negative air chamber are found.

  7. #7
    mtbr member
    Reputation: MTBeing's Avatar
    Join Date
    Jan 2012
    Posts
    1,128
    Quote Originally Posted by keen View Post
    I have seen this happen before. Why ? The fork was leaking air past the lower air spring seal (o-ring) and pressurized the lowers - enough pressure and pop goes the seal. If the Reba is a Dual Air U-turn you can also lose pressure from the top (positive) chamber which will pressurize the lowers.
    This very same thing happened to my Reba RS. Lower air was leaking out, into the upper apparently. Blew the seal right off. My lbs suggested sending it to Push for their factory service.

    Sent from my mountain bike while crashing
    Please donate to IMBA or your local chapter. It's trail karma.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,884
    Quote Originally Posted by LyNx View Post
    Easy fix...... do a service, remove the crappy RS seals, replace with Enduro seals.
    I have a had no issues w/ Rockshox seals in mild condistions, can't speak for those running in muck. That said I have never seen a RS seal just pop out w/o an internal air leak.

  9. #9
    mtbr member
    Reputation: Deerhill's Avatar
    Join Date
    Dec 2009
    Posts
    3,020
    Maybe when you service it you can install the top cap with the fork compressed a bit so there's less pressure to build up? (I don't have this air model, just a thought)

  10. #10
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    60
    Quote Originally Posted by Deerhill View Post
    Maybe when you service it you can install the top cap with the fork compressed a bit so there's less pressure to build up? (I don't have this air model, just a thought)
    I may give that a try. But if the issue is really because of a leaking seal then it won't make much of a difference.

    What was weird about this is that it happened at the bottom of a hill. I was going slow and doing a fairly tight switchback when it happened. You would have thought it would have happened earlier. I also didn't notice too much of a difference in how it felt, so if it is leaking it is just a slow leak.

  11. #11
    mtbr member
    Reputation:
    Join Date
    Feb 2010
    Posts
    1,348
    Quote Originally Posted by offroadcmpr View Post
    ... because of a leaking seal ...
    I think some of the guys in this thread are getting their seal's confused. The wiper popping off that you experienced is caused by the one of the two air-piston rod negative piston
    o-ring's leaking. It is most likely the o-ring that has the air piston rod move through it. The outer one on the seal head does not move and almost never fails. If you're lowers a run low on splash oil then the air rod will damage the o-ring seal.

    If these o-rings are not leaking, there is now way for there to be sufficient air pressure build up in the lowers to pop the wiper off.

    Put a pump on your neg air piston and see how much air it still has. If its low then pull the fork apart and change the o-ring.

    Keen's right on the money.

  12. #12
    MTB B'dos
    Reputation: LyNx's Avatar
    Join Date
    Oct 2004
    Posts
    17,222
    Haven't used an RS fork now in over 4 years, but on the older Rebas I never thought the seals were great (dust/wiper seals that is) so I used the Enduro ones and they worked fantastic, when changing the oil after changing to them for the same amount of riding/time it was always a lot cleaner. The new Fox seals seem to be good, but then again I haven't gone into my F34 yet, so who know how well they actually keep dust out. Yes I ride is very varied conditions from super dry to torrential downpours and everything in between, so my equipment gets a lot of mud so good seals are critical.

    Quote Originally Posted by keen View Post
    I have a had no issues w/ Rockshox seals in mild condistions, can't speak for those running in muck. That said I have never seen a RS seal just pop out w/o an internal air leak.
    To the OP, what Keen and the others are saying is right and when they say seal, it's actually just o-rings. Rock Shox has great exploded drawings and instruction on their site and I'm fairly certain there's a YouTube video or two floating about describing what happened to your fork - I've had a couple friends forks leak air from the POS into the NEG, which draws the fork into it's travel, but not the other way around.
    One day your life will flash before your eyes, will it be worth watching??
    MTB Barbados
    My MTB vids

  13. #13
    mtbr member
    Reputation:
    Join Date
    Sep 2012
    Posts
    84
    happened to me 1 week ago with rockshox reba.
    my fault maybe, cause i went off road with lockout on (forgot it)

  14. #14
    MTB B'dos
    Reputation: LyNx's Avatar
    Join Date
    Oct 2004
    Posts
    17,222
    Nope, not your fault AT ALL, the MC damper has a blow off valve and even set to the firmest setting it will, and is meant to blow off and let the fork be active in these situations. If it's within warranty, definitely send it in and get them to fix it. I've done exactly what you did on the older Rebas and I did it with my F34 onto square edged, concrete steps and it did what it was supposed to, no ill effects.

    Quote Originally Posted by ins@ne View Post
    happened to me 1 week ago with rockshox reba.
    my fault maybe, cause i went off road with lockout on (forgot it)
    One day your life will flash before your eyes, will it be worth watching??
    MTB Barbados
    My MTB vids

  15. #15
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    14
    How old, amount of use, were your forks have before the seals failed?

    I was reading one makers site who recommended a 100 mile full rebuilt on air springs. Is this normal?

  16. #16
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    6,884
    Quote Originally Posted by Gabe63 View Post
    How old, amount of use, were your forks have before the seals failed?

    I was reading one makers site who recommended a 100 mile full rebuilt on air springs. Is this normal?
    Sure its not 100hr ? Both my Reba Dual Air fork's had air migration problems well before a half season of use.

  17. #17
    mtbr member
    Reputation: ColinL's Avatar
    Join Date
    Feb 2012
    Posts
    1,276
    Quote Originally Posted by Gabe63 View Post
    I was reading one makers site who recommended a 100 mile full rebuilt on air springs. Is this normal?
    I think you may have misread. 100 hours is a typical service interval for rebuild. For most trail riders, this is around 1,000 miles.

  18. #18
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    14
    Actually I was looking at x-fusions site, I think some of their recommendations are crazy.
    I have to post 2 more times to link...

  19. #19
    mtbr member
    Reputation:
    Join Date
    Oct 2012
    Posts
    14
    OK 10 post now, they seem to want you to pull the shock apart every 25 hours?


  20. #20
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    1,167
    Once per month on my Reba uturn I pull the + core and suck in a couple of cc's of gear oil. When the oil no longer appears at the neg valve I add more. Its an 06 with the same seals it came with.
    lean forward

  21. #21
    mtbr member
    Reputation:
    Join Date
    Feb 2005
    Posts
    121
    What would be the reason for the wiper to pop on the right damper side? It's happening on a Revelation I just bought.

  22. #22
    mtbr member
    Reputation: tune's Avatar
    Join Date
    Aug 2011
    Posts
    157
    Could be too much lubrication oil in the lower leg.

  23. #23
    mtbr member
    Reputation:
    Join Date
    Apr 2012
    Posts
    60
    I would guess too much oil also.

    Mine is is a 2011 I bought new about a year ago. I have take it apart a few times on my own, mainly to take out the spacers to increase travel. The last time I took it apart the seals still looked good.
    I came down with the flu, and then with all of the rain Southern California has been getting I haven't had a chance to take it apart. I did get two 45 minutes rides in without any issues. So I am not sure if it was just air that got in the lowers from the last time I took it apart or something else.

  24. #24
    mtbr member
    Reputation: Kiwiplague's Avatar
    Join Date
    Jul 2011
    Posts
    1,034
    Quote Originally Posted by jaks View Post
    What would be the reason for the wiper to pop on the right damper side? It's happening on a Revelation I just bought.
    New or 2nd hand? If 2nd hand, it is possible the previous owner did put too much splash oil in the lower legs as mentioned (8ml is all RS recommends). There may also be damper oil leaking into the lower as well if the seals are worn.
    If new, then maybe the factory over-filled the lowers. Drop the lowers and see how much oil drains out.
    I don't crash, I just have slightly uncontrolled dismounts!

  25. #25
    mtbr member
    Reputation:
    Join Date
    Feb 2005
    Posts
    121
    Thanks, that must be the reason. I believe there's too much splash oil in the lowers taking up too much air volume. One temporary fix that seems to have worked is, I compressed the fork about 3/4 way until air stopped hissing out of the lowers, then I pressed the wiper (dust seal) back into place. The wiper doesn't pop out now, even when I compress the fork fully. It's interesting that the wiper appears to make an air-tight seal against the stanchions for a long time.

    I will check the oil level in the lowers later and make the fix permanent. Thanks all for your suggestions.

Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •