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2010 RS Revelation U-turn problems

scottalejscottalej Posts: 135
edited August 2019 in MTB workshop & tech
My u-turn forks went bang and dropped from 150mm to 120mm. They will come back up with the forks air pressure but as soon as you get on the bike they 'clack' back down. I can wind them down to 120mm and they seem ok at that height so obviously something has broken in the u-turn assembly.
Has anyone had the same problem? I've emailed the importer Fisher Outdoor but no reply yet.
Orange Clockwork 2007
Orange 5 2007
Just bought 2008 P7 frame (Orange fan? Me!)
Cotic Soul
Pace RC303
Marin Mount Vision 2005, for sale
Stumpy HT 2006, shite, sold
Kona Lava Dome fully rigid

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    your point of contact is theplace that sold you the fork/bike NOT Fisher.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Quite a lot of issues with this happening on the mtbr forums, its a U-Turn only issue. Rock Shox have acknowledged the fault iirc.
  • BG2000BG2000 Posts: 517
    I thought I'd reply to this thread, rather than start a new one.

    I'm just wondering what experience others have had when their U-Turns have gone pop, i.e. what repairs/replacements did SRAM provide ?

    If this is a known design fault, should I accept a replacement now that I've lost all faith in U-Turn ? I've not yet lost faith in RockShox, but the I will do if I get the slightest bit of hassle from their service centre.

    Mine just went pop on Saturday while riding at Cannock Chase. There was suddenly a loud 'clack' noise at the front after hitting a bump. The ride height then seemed to be stuck about 20mm lower and I'm guessing it's lost +ve air pressure as it drops right down when I'm on the bike (If I push down on the fork, there's no resistance until it knocks against something inside).

    Whatever went wrong inside caused the U-Turn dial to jam up as it no longer turns. I then took it easy riding back to the carpark. At least I got a morning's riding done first.

    I'm surprised though, as they'd been fine for 3 months (occasional weekend XC rides, nothing more).

    They're going back to the shop later today.
  • My Rev team U-Turn are a bit "odd" when I use the travel adjust.

    If I wind the travel down, to say 135mm, and then wind it back, I lose about 10mm travel.

    But then if I empty the air from the chambers and reset the air pressures (whcih haven't changed in the 1st place) the fork is fine.

    I'll keep an eye on mine.
  • PedjaPedja Posts: 1
    I know it's an old thread, but i know what the problem is, and the solution for it. The problem is in the u-turn upper spring assembly. When you take the spring assembly out of the fork, you unscrew the topcap from a white plastic part in order to disassemble it. The white coke with big threads should be fixed to the air assembly shaft. It rattles up and down. When you compress the fork from 150 it drops to 120 and you head a CLUNK noise (that is the white coke moving up the air shaft tube along with the piston which should be moving trough the coke, not with it).

    What you need to do is take the assembly apart, remove the negative air piston (following SRAM instructions) and compress the positive spring with a dowel (i had to use a hydraulic press because it is VERY hard to do it by hand) until it passes the ribbed part on the shaft and reaches the curved end of the pipe (airshaft). It gets stuck there, and voila, problem solved.

    Notice that, now, on the uppers, you can see the 150mm travel mark, whereas before you couldn't, because it was missing a few mm, because the coke wasn't hitting the end of the air shaft rod, lowering the total travel by the amout from end of the air pipe shaft to the ribbed part in the pipe.

    While you're at it, replace the o-rings. O, and take care of snaprings when disassembling the airshaft. They stretch easily (the compressing ones, especially the one that you remove first from the bottom of air shaft) and do not engage properly. When you pressurise the fork it holds up, but when you compress it, something snaps inside. You get a fork that holds pressure, but gives no resistance. The fork behaves like positive chamber has no pressure in it.
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