my mates pikes go through half their travel and them suddenly stop with a big knock like they have bottomed out. I dont think the lockout switch works either which suggests that the problem is probably something to do with this side of the forks rather than the coil side.
Any help much appreciated.
Sorry to be an arse but did you search? This question comes up 2 or 3 times a week.
Basically an oring has worn out and the oil has leaked from the damper into the lower legs
Yeah, it's the old oil leak problem. Need a strip down and a couple of O rings to sort it. 15 min job if you know what you're doing
(Please don't ask me to explain it!)
no worries guys, cheers for the reponce, i'll do some digging!!
ok so I have stripped the forks down, does anyone know which seal is the problem? non of the seals look particularly worn but i spose you would not notice that much anyway. I have taken some pics of the upper and lower dampening assembly. If anyone with better knowledge than i can identify the seal that would be great. I suspect its the plastic piston ring type seal on the lower assembly letting oil into the lowers but thats just an uneducated guess as i have never stripped a pair of foks down before (only my manitou elastomers back in the day)
upper assembly
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lower assembly
[IMG] 
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as they sit in relation to each other
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if its deffo oil shifting from top to bottom then its the ring on top of the lower assembly.
this sits inside the uppers so is the only seal between the two.
i'd replace the lot while its in bits mind...
sorry my bad, im being a spazz. the one on the BOTTOM of the lower assembly. next to the circlip you removed.
Mail me if need a rebuild kit 😉
Forget the red thing, that's the Motion Control unit.
If the foks are seperated, with just the uppers removed from the lowers, you can see the damper shaft sticking out of the bottom of the right stanchion.
It runs through a white plasic disc. There's an inner and outer seal on that disc. Replace those 2. I think it's the disc on the right hand side of your middle picture
Was there a fair bit of oil in the bootm of the leg, and not much in the top?
Mail me if need a rebuild kit
Or just spend 50p on 2 O rings..... 🙂
I initially thought that that seal just prevented oil leaking out the bottom of the fork leg, but yeah i see your point, it'd be good to see an animation of how they worked when moving up and down.
yeah deffo more oil in the lower leg
Yeah, replace the seals and you're sorted then.
so am i right in saying that when the forks are working correctly the small amount of oil (15ml for pikes) below the white disc in the bottom of the fork leg is for bottom out dampening?
Just be a bit careful when reinserting the red moco unit make sure you don't snag the seal on the threads, touch of grease will help.
Any further problems drop me a mail if you like.
Oil in bottom of leg is for lubrication mainly.
The small amount is just for keeping the seals and bushings sweet
cheers all for your help.....
no rotary.
ALL damping takes place ABOVE that white disc.
below the white disc you essentially have an empty lower leg with a small amount of oil sloshing about to keep things smooth.
http://www.singletrackworld.com/forum/topic/fork-issues-rs-pike-is-mr-poddy-in-the-house
Happened to me the other week and again on Sunday because I just rebuilt it and didnt replace the o rings. Got some coming now.
Except now I have no travel at all as virtually all of the oil is in the lowers. The forks are virtually rock solid.
Are they still in warranty? Hydrolocked.
Mine did the same. They replaced a cart as well as the seals.