So I serviced my forks and now they top out with a clunk! Why?

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So I serviced my forks and now they top out with a clunk! Why?

24 posts & 10 voices | Started 8 months ago by Mugboo | Latest reply from Mugboo

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Mugboo - Member

I am attempting to sort out a knackered set of forks for a mate.

They worked fine but the stanchions were kaput.

I have put some second hand stanchions that are the same size on. They are Fox Float 140RL

I closely followed the instructions on the Fox website including getting the old oil out of the damper.

I have put 160ml in the damper side and 30ml in the air side. I guestimated the the float fluid in the top of the air side.

They go up and down smoothly but they top out with a metallic thunk. What have i done wrong?

Posted 8 months ago #
kaiser - Member

on rockshox it's often the negative air pressure needs topping up/ resetting.no experience with fox i'm afraid

Posted 8 months ago #
Onzadog - Member

My guess would be that you haven't cycled them enough for the damper unit to fill with oil. Just bounce up and down on them a while on full rebound setting and it will pull oil into the unit.

Of course, if this was a while back and you've done a lot of riding on them and things haven't improved, my advice is useless.

Or, have you got the correct combination of springs and spacers in there? Is there any unrestricted travel in them or is it just that there's a bit of fast rebound at the top?

Posted 8 months ago #
Mugboo - Member

They are freshly rebuilt and I just put things back in as I found them. I did wonder if the oil just hadn't reached the right bits yet..

Posted 8 months ago #
Onzadog - Member

Then it's certainly worth trying to cycle the cartridge 20 times on full rebound. That should sort it.

Posted 8 months ago #
Mugboo - Member

Excuse the stupid question but is that slowest or fastest setting? Does it make any difference which way up?

Posted 8 months ago #
jedi - Member

rebound fully slow

Posted 8 months ago #
Mugboo - Member

Cheers.

Tried a few times both ways. I'll go try again..

Posted 8 months ago #
Mugboo - Member

Right, so I have done that 25 times on slow and still no luck!

Should I have less air in so I can get them lower?

If it helps the lockout works?

What's my next move?

Posted 8 months ago #
andrewh - Member

Had this issue on Magura Durins. Silly me had got the plastic spacers and top-out bumpers the wrong way round (at the bottom of the legs but inside) Amazed how much of a difference it made, they were horrible that way round!

Posted 8 months ago #
Mugboo - Member

Is there a wrong way round? I didn't take them out but they defo got jiggled around and could have flipped over..

Posted 8 months ago #
Onzadog - Member

Certainly worth trying less air so you can fully work the cartridge. I normally charge the cartridge before refitting the top cap to the stanchion.

Unlikely to be wrong spring/spacer combo if you've not removed anything from the rod although if something (spacer) dropped off it would present like this.

Posted 8 months ago #
Mugboo - Member

One more go then with less air, fingers crossed.

Posted 8 months ago #
andrewh - Member

I didn't think there was a wrong way but there is (Maguras anyway)
Try yours the other way round and see what happens.

Posted 8 months ago #
Mugboo - Member

Still no luck so back to the drawing board

Posted 8 months ago #
maxray - Member

I know it's time consuming but worth putting the old ones back on to see if it rectifies the problem? At least you will know if it is the rebuild or the new stanchions?

Posted 8 months ago #
B.A.Nana - Member

Mugboo - Member
I am attempting to sort out a knackered set of forks for a mate.

Let me guess?

Posted 8 months ago #
Mugboo - Member

It may be time confusing but it's also good practice

Posted 8 months ago #
Mugboo - Member

Numpty alert!

Bro in law was round last night and noticed one of the old stanchions has something circliped in the end.. So I'll try again

Posted 8 months ago #
LoCo - Member

Negative spring plate/cup for the negative spring situated on the spring assmembly below the main piston

Posted 8 months ago #
wwaswas - Member

oops.

Posted 8 months ago #
Simon - Member

Posted 8 months ago #
Mugboo - Member

You live and you learn. Just some of us take a little longer....

Posted 8 months ago #
Mugboo - Member

Amazing what a difference it makes with that negative springemygiggamy!

Thanks again folks

Posted 8 months ago #

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