Lost all the rebound on the front forks, have changed the oil and done a visual check all seems ok, the cartridge is a sealed unit so you can't do anything with it, have been told this has happened to a couple of riders in the SSDT and they had to get new cartridges, does anyone know a fix or a way round this or do I just have to buy a new rebound cartridge ?

Edited June 9, 201115 yr by Taff_d

Lost all the rebound on the front forks, have changed the oil and done a visual check all seems ok, the cartridge is a sealed unit so you can't do anything with it, have been told this has happened to a couple of riders in the SSDT and they had to get new cartridges, does anyone know a fix or a way round this or do I just have to buy a new rebound cartridge ?

You may have broken a shim or wave washer. Most cartridges come apart but you really need special tools to keep from damaging the tube, like machined blocks that grip the tube (so the endcaps can be unscrewed) but do not compress it inwards (which would cause piston seizure).

Unless you have a suspension shop nearby, you may need to replace it. Be sure, however, to have someone who has some suspension experience check it out before you do anything rash. I'm assuming you properly bled the cartridge and then set the oil level correctly?

Jon

You may have broken a shim or wave washer. Most cartridges come apart but you really need special tools to keep from damaging the tube, like machined blocks that grip the tube (so the endcaps can be unscrewed) but do not compress it inwards (which would cause piston seizure).

Unless you have a suspension shop nearby, you may need to replace it. Be sure, however, to have someone who has some suspension experience check it out before you do anything rash. I'm assuming you properly bled the cartridge and then set the oil level correctly?

Jon

Thanks for the reply,

Oil level is correct and the cartridge is bled (can only get slight resistance on the rod when pulling it up) when the forks are in the bike they compress nicely then spring back like a pogo stick, if you lift the front end you can feel a knock as if the forks are trying to pull apart ?

Did you lose rebound after you changed the oil?

Lost all the rebound on the front forks, have changed the oil and done a visual check all seems ok, the cartridge is a sealed unit so you can't do anything with it, have been told this has happened to a couple of riders in the SSDT and they had to get new cartridges, does anyone know a fix or a way round this or do I just have to buy a new rebound cartridge ?

Remove cartridge from fork, disassemble cartridge, fill with fork fluid, reassemble cartridge, then put cartridge back in fork tube, then with fork and damping rod completely depressed set oil level 160mm from top of fork tube. Cycle damping rod to make sure no air is in cartridge and check oil level again. Pull up damping rod and insert spring and preload spacer, screw on fork cap.

Did you lose rebound after you changed the oil?

When cleaning the bike after the last trial the front end did not feel right at all, with the brake on and pressing up and down on the forks I could feel a knock, checked the head bearings they where ok but found knackered wheel bearings and presumed they where the problem, whilst the wheel was out I decided to change the fork oil and thats where I am now, the wheel bearings where rough running but they where not collapsed so I'm now thinking this was not the cause of the knock from the front end, I'm now starting to think that the forks broke during the trial.

I have the phone number of a lad that had the same problem during the SSDT so I'll give him a call today along with Gas Gas and try to find a way forward.

Edited June 10, 201115 yr by Taff_d

Im sure you will find it is the shim that has failed.

Has been a common problem here in Australia with many failing on bikes with the wave shim.

Specialist repairer needed.

had this happen recently to my lads 09 after s3 round. pretty sure its the wave washer broke in the cartridge. washers cheap to buy and are more like a shim. take the lot out then dissasemble cartridge ie there is a small clip just inside of end of cartridge remove that then take out parts slowly and methodicly and investigate, lay all parts out in order for reasembly. you must load the cartidge full of oil after assembley before putting back into stanchion. If you are ok at maintenance then this procedure you can do. if its the washer broken which is common you wont believe that such a small part will cause this amount of trouble but it has an effect on the oil being squeeezed the baffles in the cartridge. hope this helps mate.

Edited June 10, 201115 yr by pandelboy

A quick call to Gas Gas had the problem solved within a hour, like Pandelboy says you have to remove and completely strip the cartridge (very easy to do if your mechanically minded) then recharge the cartridge with 80ml of oil before assembling back into the fork leg. All my internals where ok it was just a bleed issue.

Thanks for all the reply's.

Edited June 10, 201115 yr by Taff_d

Thanks for the reply,

Oil level is correct and the cartridge is bled (can only get slight resistance on the rod when pulling it up) when the forks are in the bike they compress nicely then spring back like a pogo stick, if you lift the front end you can feel a knock as if the forks are trying to pull apart ?

Be sure to check the "top out spring" above the piston, that's what acts as a bumper when the forks extend quickly. It's probably o.k. but has had to work overtime due to the lack of rebound damping. Be very careful when holding the cartridge to take the caps off as not to compress the tubing walls, otherwise, the internals are relatively simple in the Marzocchi's.

Jon

A quick call to Gas Gas had the problem solved within a hour, like Pandelboy says you have to remove and completely strip the cartridge (very easy to do if your mechanically minded) then recharge the cartridge with 80ml of oil before assembling back into the fork leg. All my internals where ok it was just a bleed issue.

Thanks for all the reply's.

I am having the same problem, not being able to bleed the air out of the rebound cartridge. I'm missing something as I do not see how to disassemble, anyone have more detailed instructions? Tried inverting cartridge and adding oil to prime but oil just runs out when turned right side up to install into fork. Also have tried over filling with air gap at 120mm and riding around for 20 minutes without any success as well. Any and all help appreciated.

From memory press in the bottom of cartridge which can be stiff and a circlip will appear, remove the clip and you will then be able to take it all apart, take note of the way it comes out and reverse for assembly.

Hope this helps.

Had the same problem on this years ssdt and only just got round to sorting it now. I have taken the leg apart and when I was taking the guts out of the cartridge two halves of a shim fell out!! Now the problem I have is where did it come from????

this is the order the stuff came off the piston:

nut

top hat thingy

small shim

large shim x2

round bit with holes in it

large shim x1

is there supposed to be 2 shims closest to the top???

Also where do you get the replacement parts from???

Edited June 3, 201214 yr by thespikeyone