Oil coming out of negative air valve on Reba Brain fork

[Pointer]

I need help.

 

I had my reba brain fork serviced on the 10th of October. Took it to local Spez shop and they did the 50 hour service on the fork.

 

Since then I only did the Berg & Bush and three weekend rides.

 

On the last ride a buddy made a comment about the amount of sag I have on my fork. 

So planning on doing a ride tomorrow I wanted to sort that out.

 

Thought I will deflate both + and - air and set it up to my required pressure.

 

When I pressed the - air side valve, instead of air coming out, oil came pouring out the valve.

 

This in my mind is not suppose to happen...

 

See attached pic.....

[Guest DieBees]

its defs leaking yeah....

[JXV]

Did you download and read the services instructions from the 'interwebs' ?

 

Is it possible you are supposed to turn the fork upside down before releasing the negative pressure valve?

[David Marshall]

The air side of the fork is not affected by the "brain" and is the normal Rock Shox dual air set up. They recommend 5ml of suspension oil or "red rum" on top of the +ve air piston, so yes it is likely some oil will leak out. How much I suppose would depend on how much was put in in the first place.  When I service a dual air I also put a little fluid above the negative air piston.

 

I would set up the fork and check that the pressures are maintained but if you are not happy with it discuss with the shop that serviced it.

[droo]

Nope, definitely shouldn't be doing that. There's only meant to be grease in the spring assembly.

 

It's not fatal, but Id get it looked at.

[David Marshall]

Did you download and read the services instructions from the 'interwebs' ?

 

Is it possible you are supposed to turn the fork upside down before releasing the negative pressure valve?

If there is oil between the +ve and -ve pistons it will get blown out when the fork is deflated upside down, as the -ve air enters the tube just below the +ve piston.  Deflating with the fork right side up for both the valves should lead to the least loss of oil

[droo]

The air side of the fork is not affected by the "brain" and is the normal Rock Shox dual air set up. They recommend 5ml of suspension oil or "red rum" on top of the +ve air piston, so yes it is likely some oil will leak out. How much I suppose would depend on how much was put in in the first place.  When I service a dual air I also put a little fluid above the negative air piston.

 

I would set up the fork and check that the pressures are maintained but if you are not happy with it discuss with the shop that serviced it.

 

They stopped that around 2010 IIRC, it's been a grease lubed system for a while now. Aside from which, even if there was oil on top of the piston, it definitely shouldn't be leaking out of the negative air valve.

 

I think somebody got some lube in the wrong hole...

[Pointer]

Thanks guy's. Will be waiting at their door when they open. So much for riding this weekend.

[Skylark]

They stopped that around 2010 IIRC, it's been a grease lubed system for a while now. Aside from which, even if there was oil on top of the piston, it definitely shouldn't be leaking out of the negative air valve.

 

I think somebody got some lube in the wrong hole...

 

On my dual air some oil does migrate into the negative chamber over time and does come spurting out the valve when you deflate it, always done that, you have to watch that it doesn't spray on the rotors.

 

Maybe this guys fork is older than 2010, when I was getting info about servicing my 2009 Rev I remember Sram service manuals said 2010 and over only grease. Though that being said many people did recommend and use oil in the air chambers of newer forks that Sram says must use grease, that advise may only apply to dual air though, not sure about the solo air or dual-position forks.

 

Perhaps the guys that serviced the fork still use oil and not grease, which probably wont hurt the fork?

[MrJacques]

I have an older +-2008 Reba Race Dual Air that I did an oil change on recently. When deflating or connecting the shock pump to the negative (lower) chamber there is oil coming out of it. I'm pretty sure it's not supposed to do that. I can see it's the thicker weight oil I put in the lower legs through the bolt holes, not the tiny bit of thinner more colorless oil that I put in the top of the positive chamber.

 

It functions fine, but I'm guessing a seal might need replacing. Any advice? Thx

[David Marshall]

I can't see how the lube oil would get into the -ve air chamber unless the seals are totally shot.  You should be able to see this by a loss of air from the chamber.

[MrJacques]

Yeah, I was mistaken, the positive chamber takes the heavier wt oil. It's the damper top side only that takes the lighter wt. There is no air loss I can see.

 

So it's probably the heaver wt oil from the positive air chamber that is leaking past the o-ring into the negative chamber. From some research it seems to have been an issue for some people. If I pull it apart again I'll try to replace the piston's o-ring.

[David Marshall]

You will need 3 o'rings.  Two 21 X 3.5 mm (20 or 22 X 3.5 will also work) for the positive and negative pistons and one 10 X 3 mm on the inside of the negative piston which seals the piston against the shaft.