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X-Post Fox RP3 - Unserviceable?!?!?!

91K views 139 replies 35 participants last post by  fansaldi 
#1 ·
So, I've been around motorsports, snowmobiles, dirtbikes and the like over the years. I've also been biking over half of my life here on earth, so I know a few things about servicing Fox shocks. This brings me to my current rant.....

I have an older RP3 shock that needs new damper oil and a nitro recharge. I've done the air sleeve (many times) and I DO NOT NEED any custom valving (aka Push). Apparently NO ONE, I mean NO ONE other than Fox and Push can recharge the nitro?!?!?!

When I used to re-valve my snowmobile shocks we had a huge bottle of nitro in the shop. A matter a 30min to re-valve, re-charge and I was back riding my snowmobile seeing what effect the changes I made had to the suspension. It was no biggie. Anyone could do it. Seriously, it isn't hard to recharge the nitro with the needle tool.

This brings me to my current dilema..... I don't want to spend $100+ dollars just to rebuild the shock to normal condition. I just want to refill the damper oil and recharge the IFP chamber. Hell, I'd be just fine using air instead of nitro, but that doesn't seem possible without the tool. (which NO ONE has, except Fox and Push)
What is everyone doing with this situation? I talked to Fox and they want $120 for a full rebuild! I'd go the Push route for a little more than that, but I'm fine with the Comp and Rebound functions.

Has anyone found a cycle/sled shop that can recharge the nitro side of things? I'm worried the needle guage is slightly larger than what the MTB shocks need.
I've found some good info online and even found a massive zip file of Fox documents with exploded views, specs, and the like for my shock. IFP depth and the like. The file even has a service update in which Fox is telling dealers that the Nitro side of my RP3 is now getting pressurized to 400psi instead of the 'normal' 300 psi. I don't even have the means to pressurize something to 400psi......

I'm really frustrated with Fox right now. Great product until it needs servicing and then I'm supposed to pay almost half of the cost of a new shock, just to rebuild my old one!?!?
I am more than competent and confident to do this myself, but how?

Any help on the matter is appreciated and I know I'm not the first to ***** about Fox's proprietary damper. Feels like a Monopoly with Fox and Push being the ONLY ones that can work on these.

/Rant, Just needed to get that off my chest!

Please tell me I don't have just 2 options!
 
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#84 ·
@ 1niceride : Nice, tommorow i will try with a tractor schrader valve, a 'standard' valve is too small and rebuilding a 'thread' on it is not a viable solution. The tractor one got a 'standard' side and a bigger side that seems of to build the correct 'thread', the one that is on the Fox suspension (RP2)

This is the part :


1 - Remove the o-ring
2 - Shave the bottom thread and get the diameter to 8mm
4 - Create the new thread in place of the old one

I get these part for free cause thay are throwing them away when changing tires... :)

1niceride, are you using air in place of the nitrogen ? No problem, no mixing with the oil... ?
 
#87 ·
If you've got that :
Logo Machine Bottle Power tool Small appliance


Then one o-ring is blasted...

1 - I opened the RP2 completly, the smallest o-ring... the one that is just above the one labelled B

Yellow Automotive exterior Parallel Automotive window part Machine


Is dead... i can not even find it, it is 'broken' in multiple parts... did someone got the specification of this ring..?

The central hole is something like 2.7mm

2 - Plus... i've lost the small ball that is on top of the central needle... someone got an idea wher i can find one ...? I thought of a bic pencil ?

I've finished my fork (F-serie RL 120), open bath... it took 30 mins, very easy job.
 
#88 ·
If you've got that :
View attachment 783874

Then one o-ring is blasted...

1 - I opened the RP2 completly, the smallest o-ring... the one that is just above the one labelled B

View attachment 783875

Is dead... i can not even find it, it is 'broken' in multiple parts... did someone got the specification of this ring..?
The central hole is something like 2.7mm

2 - Plus... i've lost the small ball that is on top of the central needle... someone got an idea wher i can find one ...? I thought of a bic pencil ?

I've finished my fork (F-serie RL 120), open bath... it took 30 mins, very easy job.
O-ring spec: .050 C.S. x .154 ID

FOX P/N: 029-05-105

Tricky little bugger to insert
 
#89 · (Edited)
Hi cort,

Thanks for your time, but it seems that you gave me the A ring .. no ?

I'm talking about the C on this picture

Yellow Line Parallel Automotive window part Engineering


If i'm not mistaken it should be something like 2.7mm ID

I suppose that the dimension you gave me are in inch ?
.050 C.S. x .154 ID => 1.27mm C.S. x 3.9116mm ID => Way too big... :)

Or perhaps i missed something ?

I used your reference to search on the web and found a russian website talking about the subject, and certainly found the one i need :

FOX : 029-08-043 / 2,5mm ID x 1mm CS, Ring rod rebound

Did someone have the diameter of the metal ball just above the C ring ? should be something like 1.2, 1.3 .. 1.4mm..
 
#93 · (Edited)
There is a store not far from me, going to check if they sell this ring.

I found this seller... it's a 25 rings package .. :) they are Nitrile ring like the stock one.

eBay | BLACK RUBBER O RINGS METRIC 2.5 ID x 1.0MM THICK x 25

@cort : No problem, it kind enought of you to have look the spec to help me out.
Seems that the schematics you post is not for my shock but i suppose this ring is the same as mine. I got a DRCV RP2 (2010), mine got a second air chamber on the top. Looking at your shcematic i can see that the metal ball i need is 1.5mm ... :)

Ok found the ball, dismantle an old hard drive and found a 1.4mm ball in a small ball bearing, it seems to fit well... :)
 
#95 ·
Something wrong ...

Everything is in place .. two problems
1- Propedal do not work anymore, on or off.. can't see the difference
2 - The rebound works only a little AND seems to only work on the last half part of the travel.

Here is my shim / washer / belleville assembly .... can somebody spot a problem ..?
RP2 7.25x2.00 from a Trek Fuel EX 8 2010

Product Lens Camera accessory Camera lens Photography


Ps : Got two shims on the spring valve (not on the picture, perhaps called a needle, i do not know the name in english)

Thanks
 
#96 · (Edited)
I'm curious about that BB that was replaced. When I remove a shim stack I always usually feed them over a wire or wire coat hanger to keep them in order. I have ADD so the wire is a must.

What bleeding procedure did you follow? It is a real pita to get right and its easy to move that ifp while bleeding it if one is not careful. I betcha there is a lot of air in it. It took me 3 times with my rp3 to get it right. I use a hypo needle filled with oil through the bleed hole to rid the air now. Plus these pistons hold air even when set into oil cause of the preloaded shim stack. So one thinks they have all the air out until they cycle the shock and spill the air out of the piston.

Make sure you plug the ifp air filler hole while bleeding to help hold the piston in place. You will find these shocks seem easy and fairly simple at first. After some time passes and you have it apart several times you will find these shocks are not so simple.
 
#97 ·
Thanks 1niceride, i'm also using a wire to keep shims/washer in the correct order.. the thing is that while dismantle the stack my elbow touch the wall .. and bliiinnnkkk .. all down on the ground .. :)
Will dismantle it again and check for air but i can't see what the air can do to the propedal not working... plus i can't hear that there is air in the shock when trying it on the bike, no Shuiuliuuiluiluiluliuli... sound.. :)

Now the Bb is a little smaller than the original one... and this can make a difference, you're right... difference is at max a tenth of a milimeter.. perhaps i can add a preload shim on the spring valve...
An other thing... i've used Motul Fork Oil 10w...

To have a proper sag i need 200psi in the air chamber... that is pretty high (my weight is 165lbs)..
 
#98 ·
Solved ... :)
The problem turns to be the pressure in the nitro chamber... do not know what i've done yesterday but there was no pressure there, the rubber joints under my schrader valve was to thick.. and i suppose it was closing the hole when the shrader was screwed in its place.
The pressure was at 400psi.... but just between the rubber and the pump... :)
I've now used a thinner joint and everything went well... propedal now works, the lever (propedal) is now consistent..
Just have to pray for the pressure to stay in... now ... :)

Thanks for your help..
 
#99 ·
I'm working on coverting a Triad shock off a 2010 Stumpjumper to an RP23 bv. physically, the body swap went without a hitch and everything is going to work as plan. However, the Triad is a 2" stroke shock reduced down to 1.8", so I have to remove the piston in the RP inorder to install the travel reducer. I've never worked on a boost valve shock before. Am I going to run into anything that I won't be able to get back together when I remove the piston from the shaft?

Also, I'm having some trouble getting the RP bled. I've been submerging the piston in a cup of oil and aggitating before installing in the body. This removes a significant amount air. It feels good on the bench, but when I put it on the bike and cycle the shock a few times, it has a noticeable pocket of air in the damper. I'm assuming this is air trapped in the piston ports that doesn't dislodge until the compression shims/bv unseats. Any tips or tricks not already mentioned in this thread? I have had zero problems bleeding Monarchs.
 
#102 ·
Good ... good

Hi all,

Just an addentum to my previous messages about the RP2 i've serviced some months ago.
The air would not stay inside with a plastic cap on the schrader valve but it will with a metal cap WITH an o-ring inside. My shock is now working perfectly for 4 months, pressure is kept inside with no problems.
I got 440 psi in it.

Happy riding to all.
 
#103 ·
This post has been Very helpful to me. My RP23 has done the deed too. Thank you everyone.

BTW. If anyone is looking for a valve with the right thread for re-pressuring our shocks. The pressure release valve from a Ford Escort/Mondeo's injector rail is exactly the right thread. Go to your local scrap yard with a long reach 11/32 socket and get yourself a few. Ford have two types of injector rail. One has a moulded in release valve but the other is fully removable. They work brilliantly
 
#106 ·
This post has been Very helpful to me. My RP23 has done the deed too. Thank you everyone.

BTW. If anyone is looking for a valve with the right thread for re-pressuring our shocks. The pressure release valve from a Ford Escort/Mondeo's injector rail is exactly the right thread. Go to your local scrap yard with a long reach 11/32 socket and get yourself a few. Ford have two types of injector rail. One has a moulded in release valve but the other is fully removable. They work brilliantly
Thanks a lot for the info, will check in the junkyard to see if i can found an Escort or Mondeo (Diesel or Gas ?).
 
#111 ·
Damper o-rings for all these inline Fox float shocks (CTD, RP, RP2, RP3, RP23 etc):
9x2.5mm (2pcs) - bumper and damper shaft seal
26,7x1,78 damper cap seal
17x3,5 IFP
4x1.2 rebound tube seal
2.5x1 compression rod seal (ctd or propedal rod)
7,5x1,5 air seal between damper shaft and shock top cap (if shock leaks air under knobs)

values are in milimeters
 
#117 ·
:)

No worries, in the end I bought the "improved" seal kit from Sheeep Israel / abagrizzli on eBay ($32 delivered). As with the Fox seals, it seems way overpriced for over the counter seals. Also it remains to be seen exactly what "improved" means!

For the needle hex adapter/tool I'll drill out a tamperproof 4 mm hex bit. Still not sourced any nitrogen.
 
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