[i-ride]

Midway through oil change/rebuild on my Marzocchi MX Comp ETA/TAS forks. Need help..

Upon reassembly of lowers to stanchions, having difficulty on right leg (this leg is positive air, -all internal- rebound damper, plunger?, etc).

The damper assembly is snuggly fitted into the stanchion-- The bottom of the damper assembly is threaded and protrudes through the bottom of the lower, onto which you thread the nut-- hence holding the uppers to the lowers. In order to get this nut to tighten, however, you need to hold the damper assembly firm. (These forks come with a long hex rod for int rebound adj-- I use it to hold the damper assembly firm while tightening nut). Here's my issue:

Once I've tightened the nut onto the bottom of the leg, the internal rebound adjustment won't turn in either direction-- leaving me with no means of rebound tweakage.

I haven't finished the job yet, so I don't know how exactly the rebound will feel....but my guess is that it will be as if it's been turned all the way clockwise, which, for this fork, is 'fast' rebound.

Can anyone provide input on this particular segment of the rebuild process for these (or similar) forks? I'm nervous that I'm close to effing up.

 

[i-ride]

any thoughts on this?

 

[sanjuro]

I know on the external rebound, once it was stuck, and I had to force it to free it (per Marzocchi instructions).

Try disassembling it and see it that fixes it...

 

[i-ride]

Hm... It's like the internal assembly threads directly to the bottom nut, though. So if you turn the rebound (assembly) CCW, the bottom nut will loosen some..

 

[sanjuro]

Hm... It's like the internal assembly threads directly to the bottom nut, though. So if you turn the rebound (assembly) CCW, the bottom nut will loosen some..

And if you loosen the bottom nut, will the rebound turn?

 

[i-ride]

And if you loosen the bottom nut, will the rebound turn?

....Yes.. but then I'm worried that the nut aint got enough purchase. Maybe it's a matter of finding the right nut torque...just enough to hold it tightly, not so much that it fully restricts reb adj? thx for helping with this..

 

[sanjuro]

....Yes.. but then I'm worried that the nut aint got enough purchase. Maybe it's a matter of finding the right nut torque...just enough to hold it tightly, not so much that it fully restricts reb adj? thx for helping with this..

Well, one possiblity is that you tightened the nut too much. A difference of 10 foot lbs might be the problem...

 

[nycurse]

http://enduroforkseals.com/id25.html

 

[sanjuro]

http://enduroforkseals.com/id25.html

How useful. Problem with internal rebound: replace seals.

 

[davep]

In order to get this nut to tighten, however, you need to hold the damper assembly firm. (These forks come with a long hex rod for int rebound adj-- I use it to hold the damper assembly firm while tightening nut). .

You problem lies with trying to use the damping adj needle as a counter torque to tighten the foot nut. When you do this, you overtorque the rebound needle to its 'stop' and then it is stuck. The same thing would happen with any threaded needle valve adjustment if you reefed on it with a wrench.

I do find a similar problem to you with both my 888 and Z1, that is the damper shaft turns when you tighten the foot nut. I solve this by strongly compressing the fork to create friction between the lowers and the end of the damper shaft (or cartrage) while tightening that last half turn or so.

I am not super familiar with that model, but lots of marz fork foot nuts have an o-ring to seal the fork with out the need to torque the $hit out the nut..

 

[i-ride]

You problem lies with trying to use the damping adj needle as a counter torque to tighten the foot nut. When you do this, you overtorque the rebound needle to its 'stop' and then it is stuck. The same thing would happen with any threaded needle valve adjustment if you reefed on it with a wrench.

I do find a similar problem to you with both my 888 and Z1, that is the damper shaft turns when you tighten the foot nut. I solve this by strongly compressing the fork to create friction between the lowers and the end of the damper shaft (or cartrage) while tightening that last half turn or so.

I am not super familiar with that model, but lots of marz fork foot nuts have an o-ring to seal the fork with out the need to torque the $hit out the nut..

real' good input here. yea, the foot nut has a rubber seal...so good point re tightening. seems like a precarious design, though
I think I've got it straigtened out now.