Specialized FSX Future Shock Fork /RS Mag 21 Service

[.RJ]

Hi,

New here, was looking for some guidance on a fork that I'm diving into. I picked up a 90's S-works hardtail in pretty good shape, but the fork wasnt returning up at all and the seller didnt know anything about it. So, time to dive in and service it... I'm confused a bit on the o-rings that I found inside the fork.

Here's the fork, carbon lowers

 

[.RJ]

Weird, I cant edit... continuing on

The fork had a pair of bushings, spacer, o-rings on each end plus an additional thick o-ring between the bushing stack and the flat washer under the seal

I realized that wasnt working on reassembly as I couldnt get the snap ring fully back in its groove (it looked like it was, but found out twice and lots of fork oil on the ground its not)
, and based on some other photos I've found, this is how it went back together.

And the damper if it helps ID the fork better

 

[.RJ]

What's the correct arrangement here? It did see one video of an alloy lower "future shock" forks and had a different arrangement, with no small o-ring on top of the upper bushing, but instead a thick o-ring and the flat washer on top of the seal not below.


Waiting for new seals so hoping to get this together correctly.

 

[Patto]

That looks correct to me! did they hold air

 

[.RJ]

yes, held air fine even with the old seals, didnt try with fluid.

 

[.RJ]

 

[Patto]

Looks great! ive just started rebuilding my original M2 also! cant seem to find decals?

 

[FluffyChicken]

So all working, if you need anymore help just ask.
They're a mag 20/21 hybrid inside, you don't have any of the negative travel of the MAG21 and keep parts from the older MAG20.


Just looked at the times, I guess not as still waiting for seals.
If the seal height changes, you may need to alter you metal washer setup.
Check bushing for wear if there has been no oil in them.

 

[.RJ]

I still need to fill with oil (again) and reassemble with new seals - but removing the fat o-ring resolved the problem of the snap ring popping out when aired up.

Looking at a bunch of youtube videos, it seems there's 3 or 4 different o-ring/washer/bushing/seal arrangements depending on the year and lower, but I cant find any service/disassembly of the carbon lower fork that include that fat o-ring - how it got in there will be an unsolved mystery... the guy that sold me the bike I dont think ever rode or serviced it.

 

[.RJ]

So I've got the fork reassembled and the bike more or less ready to ride - each fork leg seemed to move pretty smoothly independently when cycling the fork legs through their travel to set the oil level but with wheel, fork brace and brakes on, the fork gets stuck down at the bottom of its travel and wont rebound back.

This of course, was the problem it had when I got the bike, and a rebuild hasnt solved it. If I take the top caps off and pull the fork through its travel, the same thing will happen, it seems to get locked, and if I keep cycling it, it will eventually return back, and this repeats.

Any ideas on what might be going on? Its almost like something is binding the fork at the bottom of its travel.