Viewing 15 posts - 1 through 15 (of 15 total)
  • Why is my reverb still not working?
  • spicer
    Free Member

    It was squishing when sat on, so I got the basic service kit and fully serviced it (using the proper IFP tool etc). It worked perfectly for a day, then started squishing again, and the lever stopped working. A quick bleed and the lever started working, but it squished more.

    There seemed to be oil on the stanchion, and when taking it apart there didn’t seem to be as much oil left in there as I’d put in. Air had obviously migrated into the upper area (it can’t have been there after the service, as it worked flawlessly for a day). What seal/s would this be that are leaking and allowing air in? All seals ‘look’ fine, and as mentioned most are new from the basic service kit.

    I’ve not quite figured out exactly how it works, so not sure what part is not doing its job!

    Cheers

    FYI, careful when taking the inner seal head out if it’s squishing. It almost took my eye out when I undid it 😯

    spicer
    Free Member

    Also, is the lever/hose an independant sealed system to the post internals, or are they connected? Just trying to figure out if a leaky lever/barb could allow air into the internals?

    zer0c00l44
    Free Member

    Could be a number of things and yes the lever and hose are independent. When the button is depressed it forces oil trough to move the post head poppet which then allows the post to move up and down. If the post head poppet is in place then no oil should be able to escape from the post when the remotes not connected.

    You went to all the trouble to completely strip the post you should have got a full service kit and changed all the seals. Just because the seals look new doesn’t mean they will still work. I don’t know but could be that under pressure the oil is coming out of the inner seal head.

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    spicer
    Free Member

    Thanks. And yeah, in hindsight I would have bought the full service kit 😀
    I thought that was for if more major parts such as bushings needed replacing, but mine are ok so didn’t bother.

    I was very against paying the £80 or so for a service (I got the post for £130!), but taking into account the cost of a full service kit, tools, and oil I might as well have just sent it off. Nice to know how to fix it yourself though!

    cchris2lou
    Full Member

    No point doing an internal service if you are not changing the inner seals.
    Your post needed a service in the first place because the seals are damaged and air and fluid are mixing.
    O rings are cheap but getting the right size is a pain.

    andyl
    Free Member

    if it’s just o-rings you need then look on ebay as plenty of cheap fork seal sets (eveilhomersimpson used to sell them for rockshox). I think the full kit comes with wear pins and lots of other stuff. The pins might be handy if you have play though.

    zer0c00l44
    Free Member

    You will need to buy the full kit as you wont find the specific seals for the seal head off any seller on ebay unless they are selling those specifically.

    To understand how it works more betterer you can look at it like this. When a Rockshox fork is locked out (non bladder lock out like in the newer models Pike etc) there is a lot of pressure on the compression dampers bottom seal and also on the rebound dampers seal head seals (inner and outer) because the oil is trapped in between the 2 dampers and the seals have to hold it in place. Well thats similar pressure to the seat post that is basically constantly locked out until you need it to drop. The oil (when you sit on the saddle) is forced against the seals in the seal head. Over time and use these can fail or begin to fail and slowly allow oil to move past them and cause that little drop and squelchy noise you have. It can only be sorted by changing them over. No matter how good they look you have to remember you are dealing with massive pressures inside a very small space so looking by eye will mean very little.

    Oil on the stanchion when taking it apart would indicate faulty seal head seals.

    LoCo
    Free Member

    IFP seal/s will be leaking or the inner seal head seal will have been pinched and is leaking.
    or you have a faulty seat for the inner shaft.

    pipiom
    Free Member

    Mine went back today after 5 failed (after a while) bleeds

    swanny853
    Full Member

    OP, if you haven’t seen it, this can help show how it works.

    Theoretically you can do a bit of deduction from the cross section to work out which seal failure is to blame. For example, mine slowly loses air but the ‘lock’ stays perfect, so it shouldn’t be the IFP seals or the ones at the top of air shaft. But then I’ve replaced the inner seal head inner and outer seals, the air valve, the air shaft bottom o-ring and I can’t see any scratches, so maybe not reliable!

    And OT, but LoCo, do you know if the ‘new’ reverb seals, IFP etc will fit the old model?

    zer0c00l44
    Free Member

    In the new kits they supply a new black plastic ifp and they do fit the old model ive done it. They seem better in fact

    LoCo
    Free Member

    Yes they will, although they’re still not available in this country, were due this week but eta has gone back to TBC 👿

    swanny853
    Full Member

    Interesting, any idea how much they’d cost for us non-service people?

    spicer
    Free Member

    Thanks for the info all. Zero, I understand your point re the seals wearing, I was just pointing out that there were no obvious nicks or deformities in them, thankyou for the input.

    However, if when serviced you should just get the full service kit (approx £40), then why does the basic service kit (approx £10) exist? LoCo, whats your take on this? I thought leaky air/similar = basic service kit. Wobbly post etc = full service kit?

    I have the full service kit on the way either way!

    tillydog
    Free Member

    AFAIK, the basic service kit is sufficient to strip down the post enough to clean and lubricate the “mechanical” moving parts – i.e. the top collar, the outer tube, the brass keys and it contains a new lower bushing (charger bushing) which is (AFAIK) the first thing to wear and cause a wobbly post. For ~£10, that seems OK.

    There is no need to disturb the oil/air part of the post (other than taking the air valve/bottom cap off the bottom of the piston rod) to do the above.

    It will not solve any ‘sponginess’ problems (and probably not air loss, unless you are (un)lucky).

    As I understand it, the main piston seal (especially), and the two IFP seals would be the culprits for sponginess (IMHO), and the inner air cap seal for air loss, but they are only included in the full service kit (together with lots of replacements for other stuff, but *not* the top cap bushing which is only available as a separate assembly). All I would want from the full kit are the 4 seals (and their backup rings, and maybe 1 or 2 static seals) in addition to the basic service kit to be able to fully strip down and rebuild the post, but that kit is £30-40 more than the basic one.

    I know there is some info on the O ring sizes for these seals on MTBR, but it would be really nice if someone could measure the 4 seals above from the full service kit, as (IMHO) the seals should be replaced as a matter of routine if the post is stripped down past the stage needed for the basic kit.

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