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I have a Heavy duty single plate clutch in my R32 skyline, when my engine is cold the clutch will release with the pedal about half way out (were i want it), then after driving my car for a while when my engine/driveline heats up, the clutch will relaese right at the top of the pedal.

Does anyone else have this problem, anyone know what causes this, and how to fix so its the same when hot and cold, my previous R32 didnt have this problem??

cause:

could be air bubble in the lines.

oil cant be compressed no matter what temp it is. but air can. when you car is cold, and air bubble will be fairly dense(small volume) so when you press the clutch you don't compress in down much before it will push/move the oil, say 1/4 stroke, so you still have 3/4 of usefull push. when you release the clutch the gas doesnt decompress much and your clutch picks up early, or normally.

but once your car heats up the gas(air bubble) expands and its volume it bigger. so then when you press you clutch you have to compress the gas down much more before it will move/push the oil. so you have already used up some of you clutch pedal stroke to compress the gas, say half stroke, and your only left with half usefull push. so when you release th clutch the gas will decompress first , half your return stroke, and your clutch then picks up much later than when it is cold.

fix:

bleed lines through.

Does it do it even if you don't give it a flogging?

When my clutch (xtreme XHD 9puk) was new it engaged just off the floor; slowly its engagement point has moved up to just above half where it is now.

When the clutch hasn't copped a flogging it engages just above half nicely with a hard grab. Give it a flogging and its grab point moves to just before the pedal is completely out, at that point it does start to slip on brisk changes.

Sounds sort of similar BUT mines done a solid 70,000km's so its nackered. ;)

So try...

1. Next time it does it stick your arm up under the car and make sure the slave can easily push all the way in (i.e not holding the clutch in which would give the pedal feel of a higher engagement)

2. Have a feel for the free play of the fork and note any differences when its cold.

3. Ensure the master cyl's rod is adjusted with some free play when the pedal is all the way out; even if it means shifting the engagement just off the floor. :)

check that the clutch is adjusted properly. Sounds like pressure is not being allowed to escape the system and so as it all heats up, the fluid expands and starts dissengaging the clutch, which means higher pedal.

Climb under the car and check that the piston on the slave can be pushed back easily by hand. If it can't then I'm right. Check that you have a genuine r32 master cylinder too. S14 ones fit and cause this problem as they are a touch shorter in the body so the piston doesn't move back far enough when the pedal is up.

You should have enough range of adjustment at the pedal that you can pull the piston back enough to release the pressure. If that doesn't work, start looking for a new master cylinder...

hrmm interesting enough a non-genuine master cyl too.

I believe the brand was Protec. I go through ~ 1 per year. :S

This current one has started leaking. This clutch has been through now 3 master cyls.

Time to stop stuffing around and buy a genuine I think.

my grab point is just below the pedals resting point.. i consider this better as it allows you to quickly kick the pedal on gearchanges instead of having to journey to the bottom of the pedals travel..

Love it, Xtreme ftw

hrmm interesting enough a non-genuine master cyl too.

I believe the brand was Protec. I go through ~ 1 per year. :S

This current one has started leaking. This clutch has been through now 3 master cyls.

Time to stop stuffing around and buy a genuine I think.

i use the same protec one, SO with the pedal in the normal relaese should i be able to push the slave rod back into the slave??

Whats the price of a genuine master?

Thats correct. You should be able to push the slave rod back in to the slave; in other words no real pressure on the fork.

I have no idea what the price of a genuine master is worth; slaves are around the $90 mark vs $40 for aftermarket. Aftermarket master set me back $75. My aftermarket was identical in every way to the genuine. everything was the exact same length.

Joel, my factory master is still going perfect 14 years on, i go thru none a year :)

Dorifto sushi, do u have short legs? maybe try moving the seat closer, i know what ur saying but it really doesnt enable you to engage/disengage the clutch faster etc

I destroyed my factory clutch at 140,000k's, and got an Exedy Heavy Duty one put in. after about a week, I noticed the exact same symptoms you mentioned... especially varying with heat. I took it back to the clutch place, and it turned out it was an air-bubble in the clutch line. had it bled properly and no problems since. and that was seven months ago.

  • 2 weeks later...

i bought a non genuine one from sum1 off here!!! the arm is a different length and therefore my clutch travel is hopeless!!! i got it adjusted all the way out!! still rubbish!!! IN OTHER WORDS BUY A GENUINE ONE!!!

If the arm length is different then you bought or were supplied the incorrect one. :(

The correct one is identical; works exactly the same. BUT I've had mine shag out a few times.

Buy genuine because they last longer not because the arm length is different. >_<

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