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  1. #1
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    air spring questions on 2016 Fox 36

    I think my air spring isn't functioning 100% correctly and I'm curious if anyone else has observed similar behavior in their fork and how you addressed it. long post coming.

    I wanted to try adding volume spacers in order to reduce psi a bit and retain support in the mid- and bottom-end of the travel. when I depressurized the air spring, my fork sucked down way into the travel. perhaps this is normal, if only the + air chamber is depressurized and the - chamber retains pressure? not sure. in any event, when I removed the air top cap, there was clearly pressure underneath as the top cap and transfer rod were pushed up and out of the fork (fairly gently, thankfully). so I interpreted this as air trapped in the fork lowers.

    I cleaned and slick honey'd the air transfer rod and reinstalled (without adding any volume spacers) thinking that perhaps all I needed was for the air spring to equalize. however when I repressurized the fork to 60 psi as per Fox's instructions, I could not get the two chambers to equalize -- I believe this should have been evident by the pressure dropping on my shock pump when the - spring got pressurized.

    so I disassembled the top cap again, thinking that perhaps there was too much slick honey in the little cut-out area on the air transfer rod where the pos and neg springs should equalize. cleaned the transfer rod cutout, reassembled, same problem--air chambers won't equalize.

    so I dropped the lowers on my fork to remove any air trapped, cleaned and serviced the seals/foam rings/lower legs and reassembled per Fox's instructions -- repressurizing the air spring to 60 psi before reinstalling the lower legs. when I had everything back together, the fork would not compress at all and felt totally locked out. depressurized (fork sucked down again) and repressurized, felt a little better, but there was clearly alot of air that had again been trapped in the lowers. so I did the zip tie trick and released a good amount of air from the lowers. after that, when I aired back up, the air spring still didn't noticeably equalize, but it felt relatively normal on a test ride -- still a little firm for the pressure I was running but otherwise functioned normally.

    so something doesn't seem right to me and I suppose the next move is to disassemble the whole air spring and see what's going on inside, but I'm curious if any of you guys who have been riding the 2015/2016 36 have had similar behavior -- fork sucking down when you let out all pressure, not equalizing when you air it back up, getting significant amount of air in the lowers etc. -- and how you addressed it. any thoughts?

  2. #2
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    Are you installing the top cap and transfer rod with the fork compressed? If you are then it will happen as you describe.

    With the fork fully extended and the transfer rod removed drop the fork into its travel slightly to allow you to guide the transfer rod into the air piston. Tighten the top cap and add 60psi of pressure to the fork, compress the fork within the first 5-10mm of travel to allow the chambers to equalise. Once this is done set the pressure to what you want it at and again compress a few times just using the first 5-10mm of travel. It will then be fine.

  3. #3
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    thanks Rick. I made sure the fork was fully extended when I reassembled. it actually still feels quite sticky in the initial travel, I feel like it was much smoother and closer to Pike-feeling when new (two months ago) so I think another tear-down with a full service of the air spring is in order.

    out of curiosity, when you equalize the pos and neg air springs, do you see the pressure drop on your shock pump and if so, by approx how much? if it's just a couple of psi I suppose I might not notice it on my analog pump. alternatively, when I've tried to equalize with the pump disconnected, I haven't been able to feel the springs equalize either.

  4. #4
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    might be talking to myself at this point, but in case it might help someone else I'll close the loop on this thread. disassembled the fork again, and once again when I let the air out of the spring the fork sucked down. removing the lowers didn't resolve the issue -- the air shaft was still sucked up into the stanchion. removed the air spring top cap and it still didn't release the vacuum, but at that point I could pull the air shaft out of the bottom of the stanchion and this finally released the vacuum in the air spring. after that everything went smoothly. when everything was back together, the air springs equalized easily.

    anyway, not sure how the air spring originally pulled this vacuum, but I probably made it worse when I first pulled the top cap to mess with the volume spacers.

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