I took my Reba apart last week to service the lowers and remove an internal spacer from the air spring assembly.
Today I checked the air pressures and they have dropped.Seem to have lost more from the negative chamber,and a little bit of oil sprayed out from the negative valve when I let the air out to reset them.

Whats the diagnosis?O rings on the air spring seemed to be good in good condition,when I dismantled them……..
New o rings required ?
Or could it be the valve/valve core?

How much down were they? Sure it's not just the loss from re-connecting the pump?? The -ve will appear to lose more as it's a smaller volume to start with so re-connecting the pump has a bigger effect on losing pressure.
I get the odd small amount of oil coming from the -ve valve on my Reba air U-turns…….never really worreid about it. They did it most when new & then it settled down so I assumed it was just from the build.

Losing about 40psi over a week or so.Before I serviced them the reading would remain the same when I reconnected the pump from when I last set them,so I

n

m suspecting a slightly leaky valve core.I might stick the valve in some water to check for air loss,before I disasseble the forks again.Anyone know are these standard Schraeder tyre valve cores?

Ahem,just found a small o ring on the garage floor…………..
😳

It`s tiny,aprrox 5mm diameter,smaller than the o rings on the air spring assembly iirc.

Any ideas where its from……?

there is a tiny o-ring that lives inside the valve cap. If you don't have on in there then that's most likely what it is. …and if you have a leaky valve then maybe the o-ring in the valve cap was previously stopping air leaking any further. Until it fell out.

Thanks Julian.So this tiny o ring just sits in the bottom of the negative valve cap?Never noticed it before…….

I didn't take me air spring assembly apart – just removed, cleaned & re-oiled (apart from the 6ml in the air assembly)……

I'd say that'll be the cause of your leak then!?
Only place I came across a small o-ring was on the top of the damper side, beneath the gold floodgate cap. I think only the remote lock-out forks have this floodgate cap.

I seem to rememberwhen looking through the service manual though that the inside of the air cartridge holds numerous small internal o-rings. It might be one of those. Probably best to see if it's the valvecap one mentioned above & if not, then take it to bits again…..

Turn the bike upside down when changing negative pressure and the oil won't spray out.
Ps make sure you top it back up if you lost it all or the seal won't work very well …

There were a couple of schraeders in the service kit I got but mine were fine so I didn't change em. They look identical to the ones I got in Halfrauds a couple of years back though.

yes. As far as i know its supposed to be there to keep dust out rather than air in though! You might want to think about trying a new valve core. I've never changed one on a fork or shock before but i guess its like a car one ie screws out with a specific tool. Give TF Tuned Shox a ring, they are very helpful and knowledgabe and if they think that's the problem too they will post you a reliable (ie for high pressures) one for not a lot of money.

Ta chaps.
I

g

t harm to take out the core and swap it with a new one anyway.

I recall I had a bit of a fight to depress the air chamber base plate to remove the circlip,possibly because I hadn`t managed to get every bit of air out,so maybe I displaced a seal in the valve?

Also anyone know where I can find an exloded view parts diagram of a Reba?

Checked the SRAM website but can only find the service guide.Just want to check how many and where all the o rings should be in the air chamber……… 😳

Don't think there is one – I think you'll have to trawl through the service guide & make a list or something.

Just stuck the lower neg valve in a bowl of water and no bubbles so thinking it must be a misplaced o ring in the negative air chamber.

Oh well,I think I`ll be able to dismantle forks blindfolded by the time I finish.

Or I might live with pumping a bit of air in for now and just ride………