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Is my DHX 5 air stuck down?

gtd.gtd. Posts: 626
edited March 2012 in MTB workshop & tech
Was riding home from work, got off the bike and pulled the back brake and pulled up on the bars to wheel my bike through a kiss gate on its back wheel.

When I got back on the shock was siting lower like there isnt enough pressure in the air can but still works and hasnt bottomed out as the travel o ring is still on the shaft.

The shock extends when I'm off the bike but when Im on it its sitting low.

I think Ive lost about 20 psi when I checked the pressure in the air can.

Any ideas? is it "stuck down"?
Mountain: Orange Patriot FR, SubZero & Evo2LE.
Road: Tifosi Race Custom.
Do it all bike: Surly Disc Trucker 700c/29er

Posts

  • gtd.gtd. Posts: 626
    Looking at the shock compared with my old Rock Shox Monarch that has the same i2i and stroke it has half as much shaft showing. Guess its stuck down?

    What is the best thing to do?
    De-pressurise and compress then release the shock with the valve core removed until it returns to full extension then service with new seals?

    Might change the damping oil whilst I at it as the pro-pedal doesn't do much to reduce bob I think it needs heavier weight oil?
    Mountain: Orange Patriot FR, SubZero & Evo2LE.
    Road: Tifosi Race Custom.
    Do it all bike: Surly Disc Trucker 700c/29er
  • supersonicsupersonic Posts: 82,708 Lives Here
    Inflate to your usual PSI/sag and see what happens?
  • cooldadcooldad Posts: 32,599
    Sounds like it needs a good service. Basic aircan is easy, but anything else I'd consider a pro. Just had one fully serviced by Locotuning - damping recharged etc, and I can recommend - came back like new.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • gtd.gtd. Posts: 626
    It was supposed to have been serviced before I got it, it has had a new aircan and seals fitted

    It looks like its half stuck down which explains where around 20 psi has "gone" into the negative chamber.

    I'm quite technically minded and good at fixing things. I fix small engines at work.

    I've been collecting information on doing a service on the DHX and DHX air and its fairly simple main problem is getting the oil circuit bled.

    If i change the oil weight pro pedal should work better, I'm quite heavy have to run 300 psi air can pressure and still the sag is more than Fox say it should be. According to the manual I should run 6.3 mm of sag and I run around 10mm
    Mountain: Orange Patriot FR, SubZero & Evo2LE.
    Road: Tifosi Race Custom.
    Do it all bike: Surly Disc Trucker 700c/29er
  • 386ka386ka Posts: 479
    GTD. wrote:
    which explains where around 20 psi has "gone" into the negative chamber.
    Or to your pump, to display a reading on the meter. You are aware that every time you connect the pump to the shock it looses pressure due to pressure differential?
    A much loved, Giant Trance X3 2010
  • gtd.gtd. Posts: 626
    Yes I was aware of that, I had factored that in. The pressure drops each time you connect the pump as the pump hose and bourdon tube in the guage need to fill with air.
    Mountain: Orange Patriot FR, SubZero & Evo2LE.
    Road: Tifosi Race Custom.
    Do it all bike: Surly Disc Trucker 700c/29er
  • gtd.gtd. Posts: 626
    cooldad wrote:
    Sounds like it needs a good service. Basic aircan is easy, but anything else I'd consider a pro. Just had one fully serviced by Locotuning - damping recharged etc, and I can recommend - came back like new.

    Damping circuit doesn't have a nitrogen charge in the DHX 5.0 Air boost valve (unless its one of the OEM Specialized ones) it uses a schrader valve on the piggy back.

    Its just a case of strip, check and replaces seals and o-rings, refill the oil circuits through the fill port on the shaft above the eyelet and bleed through the bleed port above the rebound control, then the port in the IFP making sure the IFP height is set right.
    Mountain: Orange Patriot FR, SubZero & Evo2LE.
    Road: Tifosi Race Custom.
    Do it all bike: Surly Disc Trucker 700c/29er
  • cooldadcooldad Posts: 32,599
    GTD. wrote:
    cooldad wrote:
    Sounds like it needs a good service. Basic aircan is easy, but anything else I'd consider a pro. Just had one fully serviced by Locotuning - damping recharged etc, and I can recommend - came back like new.

    Damping circuit doesn't have a nitrogen charge in the DHX 5.0 Air boost valve (unless its one of the OEM Specialized ones) it uses a schrader valve on the piggy back.

    Its just a case of strip, check and replaces seals and o-rings, refill the oil circuits through the fill port on the shaft above the eyelet and bleed through the bleed port above the rebound control, then the port in the IFP making sure the IFP height is set right.
    Which is why I used Loco. Seals are one thing, all the other bits are another.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
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