[hidperf]

I've been fighting this for a week now.

Just retuned my brand new RT3 and I can't prevent the IFP pressure from leaking out before I remove the shock pump and IFP adapter. :madman:

Manual says 350psi so I'm using the shock pump that came with the shock and the SRAM IFP adapter, but as soon as I start unscrewing the IFP adapter, still attached to the pump per the SRAM manual, PPPFFFFFTTTTT and out comes the pressure.

I already replaced the o-ring on the IFP because it ripped on the third use. I've greased up the threads and the o-ring. I'm now at the point of giving up.

Help me MTBR. You're my only hope.

 

[Scotth72]

You are not releasing the pressure when you unscrew the pump. It should come off with a bit of a pop.
If you are reconnecting the pump to check the pressure, that is where the pressure is going. The volume of the ifp is less than the volume of the hose and pump.

 

[hidperf]

You are not releasing the pressure when you unscrew the pump. It should come off with a bit of a pop.
If you are reconnecting the pump to check the pressure, that is where the pressure is going. The volume of the ifp is less than the volume of the hose and pump.

Normally I would agree with you since that's been the case when setting the fork and shock pressure. And this is definitely NOT a pop, it's a leak.
But in this case that's not what's happening. And I know that because if I try to screw the IFP and pump back on, any air that might have been left in the shock leaks out from around the IFP adapter before it's even sealed and reading in the gauge.
If I did the same thing on the canister side or the fork, the gauge would snap into place when the schrader valve opens.

I tried to take a video but my batteries in my camera are dead and I can't hold my phone and do the work at the same time.

This is driving me MAD!!!!!

Edit: After some more searching I did find an ancient thread on here where someone was having the same problem and they drilled out the center of the IFP adapter where it touched the core.
It didn't take much, but I can now fill the IFP correctly.

Now on to my other post retune problem.

 

[trailbildr]

Yeah, you are right about the IFP fill drama... The adapters that RockShox sells don't work correctly without modification.

mk

 

[Erock503]

Yeah, you are right about the IFP fill drama... The adapters that RockShox sells don't work correctly without modification.

mk

Wtf, lol, I just bought an adapter too. Can you elaborate what needs to be modded? Second thanks man, nice to have resources like you on the forums!

 

[mullen119]

They work fine without modification. The key is to not unscrew the pump from the adapter, but instead, unscrew the pump and adapter together. You will hear a little air escape, but fear not as that air is releasing from the pump, not the shock.

 

[Scotth72]

Yeah, I have been using two different stock adapters for a couple of years without a problem. Perhaps they changed the design?

 

[MarcusSommers]

I filed off the threads on the adapter, so it no longer screws into the damper body. Now I just press it tightly against the shock damper body and after filling I can quickly pull it off without losing air. I don't know if this would work with a pump, unless you had an extra hand, but works well with a nitro set up.

The IFP chamber is so small and under such high pressure that the slightest leak makes a big difference. I think its funny they even suggest using a hand pump. The monarch XX needs nearly 500psi some years, and the 350psi required by the rest is the very max that a hand pump can supposedly reach. I don't believe anyone is actually gettting 350 psi from their hand pump anyway.

 

[hidperf]

Wtf, lol, I just bought an adapter too. Can you elaborate what needs to be modded? Second thanks man, nice to have resources like you on the forums!

This isn't a problem with all of them, it just happened to be a problem with mine and some other people on here, which is where I got the idea for drilling the adapter. I used an .093 bit BTW.

Before


After


By altering the point in which the Schrader valve is depressed, it now waits until the O-ring is seated before depressing and releasing the valve. Originally, it would make contact with the valve before the O-ring sealed the orifice, releasing any pressure already in the IFP. Once I had it pumped to 350psi and began removing the IFP adapter, the valve was still depressed after the seal of the O-ring was broken which let all of the air escape from the IFP and the pump hose.

Edit: IF you have to do this modification, take out as little material as possible. If you drill more than you should, it will NOT depress the Schrader valve core and you'll have to buy a new adapter or get creative with epoxy and a drill bit.

Another tip. The O-ring on the adapter are fragile, probably because it's so small. Mine lasted for three uses, even greased up, which put me behind on the rebuild.
I ordered 20 Buna-N 70 1mmx4mm O-rings from The O-ring Store, but I should have went with a stronger material because I've already went through three of the new ones before finally getting everything squared away on filling the IFP.

They work fine without modification.

Obviously this isn't the case for all of them.

The key is to not unscrew the pump from the adapter, but instead, unscrew the pump and adapter together. You will hear a little air escape, but fear not as that air is releasing from the pump, not the shock.

This is true. That's how mine works AFTER I modified it.

Yeah, I have been using two different stock adapters for a couple of years without a problem. Perhaps they changed the design?

It's possible that they just used a different brand of Schrader valve core and it's longer than the majority of them.
I did find a thread on here as far back as 2009-2010 where someone was having the same problem. That's where I got the idea for drilling the adapter. So apparently it's been an ongoing random problem for a while.
Edit: Here's one from 2012

 

[hidperf]

I filed off the threads on the adapter, so it no longer screws into the damper body. Now I just press it tightly against the shock damper body and after filling I can quickly pull it off without losing air. I don't know if this would work with a pump, unless you had an extra hand, but works well with a nitro set up.

The IFP chamber is so small and under such high pressure that the slightest leak makes a big difference. I think its funny they even suggest using a hand pump. The monarch XX needs nearly 500psi some years, and the 350psi required by the rest is the very max that a hand pump can supposedly reach. I don't believe anyone is actually gettting 350 psi from their hand pump anyway.

Yeah, I pretty much max the hand pump out when filling it. Needle goes all the way around the gauge.

 

[brentos]

I had the same problem last year. Frustrated in the garage. Let all the air out, broke the o-ring. I had to drill mine out too.

Maybe I could have screwed the Schraeder core in a bit too? RockShox has never been great about consistently screwing in the cores. I've had similar problems on main chambers too.

 

[hidperf]

I had the same problem last year. Frustrated in the garage. Let all the air out, broke the o-ring. I had to drill mine out too.

Maybe I could have screwed the Schraeder core in a bit too? RockShox has never been great about consistently screwing in the cores. I've had similar problems on main chambers too.

Impossible! I've been told that this has never happened before

I did take my core out and reseat it but it made no difference. Chalk it up to supply chain changes.

 

[Warp]

I wish someone would design a proper adapter where you would screw/unscrew the part that engages the core of the valve, so it could be connected and disconnected without risk of losing pressure.

This system is simple and works, but it depends on the core to be always at the same spot and the adapter being correctly machined.

I've used this and the (old) Marzocchi adapters and both were a PITA to use. It shouldn't be.

 

[bing!]

I use the steel one from the vivid wrench. it works mas better than the red alu one bought on its own.

 

[trailbildr]

So this IFP fill tool thing has been bugging me. I've got a stubborn either shock or IFP tool that wasn't doing what it needed to do. I didn't want to start boring out the IFP tool, all trial and error-like to find the right depth to get this thing to disengage without dumping the IFP. I came up with a simple solution that allowed me to deal with this one IFP and others in the future.

I grabbed my Specialized rear shock floor pump (Air Tool UHP Floor Pump, PN 472E-9085) with the magic schrader chuck on it that allows you to air up your rear shock without losing pressure. I was trying to figure out how to use the architecture of the double-threaded head to work the same way with the IFP adapter screwed into the end of it.

I had a spare IFP tool so I bored it out with a 3/32" bit. I cut a 14g spoke ~23.85mm long and threw it down into the IFP adapter. I screwed the IFP adapter on and it didn't engage the IFP valve. I then screwed the back of the chuck in so that the pin that usually directly contacts the valve core on the air can pushed the spoke forward and engaged the valve core on the IFP, registering the IFP pressure on the gauge. I added some pressure then unscrewed the threaded chuck to allow the valve core to reseal and then I could remove the IFP tool without losing air.

That's the cheapest, easiest fix that I've found to this issue.

I hope that helps somebody out with this issue.

mk

 

[mullen119]

So this IFP fill tool thing has been bugging me. I've got a stubborn either shock or IFP tool that wasn't doing what it needed to do. I didn't want to start boring out the IFP tool, all trial and error-like to find the right depth to get this thing to disengage without dumping the IFP. I came up with a simple solution that allowed me to deal with this one IFP and others in the future.

I grabbed my Specialized rear shock floor pump (Air Tool UHP Floor Pump, PN 472E-9085) with the magic schrader chuck on it that allows you to air up your rear shock without losing pressure. I was trying to figure out how to use the architecture of the double-threaded head to work the same way with the IFP adapter screwed into the end of it.

I had a spare IFP tool so I bored it out with a 3/32" bit. I cut a 14g spoke ~23.85mm long and threw it down into the IFP adapter. I screwed the IFP adapter on and it didn't engage the IFP valve. I then screwed the back of the chuck in so that the pin that usually directly contacts the valve core on the air can pushed the spoke forward and engaged the valve core on the IFP, registering the IFP pressure on the gauge. I added some pressure then unscrewed the threaded chuck to allow the valve core to reseal and then I could remove the IFP tool without losing air.

That's the cheapest, easiest fix that I've found to this issue.

I hope that helps somebody out with this issue.

mk

That is the exact design of Manitou's ifp adapter. I never personally had issues with Rockshox adapters, but always thought Manitou's was a far superior design.

 

[J. Random Psycho]

Definitely do the push rod mod.

Another instance of Monarch IFP tool (aluminum, red) not sealing before it engages valve core in a 2014-ish Monarch R. I got two of the same ideas as described here, drilling out and letting a push rod through the adapter. Decided to sanity-check them with a web search and voila, this thread came up.

Nice to know Manitou has thought through the devil in details before RS did, as usual.

And I think the Schrader valve cores in RS shocks are all "standard", as per this document by Schrader International. See "Standard Valve Core" in schematics at the end of document. This makes me think that the poor reproducibility of the issue is in shock damper bodies being different, not valve cores nor adapters.

(Note there's also a "JRA Valve Core"; too bad we don't have these on bicycles! Or do we?)


PS. I drilled the adapter out with a 2mm bit, and used 22.6 mm long piece of a 1.5mm spoke as the push rod. This totally worked and is indeed vastly superior to the half-assed unmodified adapter. With the mod, it's not possible to lose pressure when detaching pump head from adapter like you would with a common Schrader valve. Consequently it's also not possible to tear the o-ring.