Clutch Disengagement Problem

[Shaun]

Ok, ive just spent the last few hours searching, but havent found anything definative, so heres my problem:

Im having clutch disengagement issues; when i coast up to a set of lights or a roundabout and put my foot on the clutch to put it in neutral, the gearstick doesnt want to disengage from the selected gear. I have to force it out the gear and the car wants to still lurch forward as if the clutch is still slightly engaged. Also, if i dont FULLY depress the clutch into the carpet, its usually quite difficult to select 3rd and 4th gear unless the engine and gearbox revs are exact.

This has only started hapening the last few days.

Its an R33 gtst gearbox behind an rb26 in an r32 gtst. The clutch is brand new, the slave cylinder is as old as the gearbox (no idea), and the master cylinder is an original item as far as i know. I havent bled the clutch yet either.

Im hoping the slave is not pushing the fork thingy in far enough, as that would be the cheapest fix. Oh, and im also interested in getting a Nismo bigger slave cylinder. Is this a worthwhile thing to do??

Any help would be greatly appreciated.

Shaun.

[NYTSKY]

Try adjusting the main cylinder on the clutch pedal. Worked wonders for me.

[Shaun]

How do you do that? Is there a thread on the pedal under there or something?

Shaun.

[QWK32]

yep. where it attaches to the top of the clutch pedal there is some adjustment.

in the pic: the blue line is the firewall. the red arrow is pointing to where it attaches to the clutch pedal. the yellow arrow is the nut you have to undo to be able to screw the shaft which gives you your adjustment. just make sure that after you make the adjustment your clutch fully disengages.

[Shaun]

This is the best forum ever!! Thanks for the info.

Ill give that a try before i spend more coin.

Shaun.

[blind_elk]

A larger slave cylinder will only make the problem worse.

Is the pedal box, where the clutch pedal attaches, still ok?

[Shaun]

A larger slave cylinder will only make the problem worse.

Is the pedal box, where the clutch pedal attaches, still ok?

Why would a larger slave make the problem worse? I thought the Nismo item might provide more movement or something, but i really dont know.

I havent had a look under there yet; ill have a look and get back to you. Im hoping i can adjust the clutch pedal and all will be ok, but the car has had some heavy single plates in it through out its evolution, so it is possible that they have taken their toll on the pedal box. Hope not though.

Shaun.

[Shaun]

Ok, i got under there tonight and the pedal box is ok, ie; there are no cracks in the welds or anything like that.

I could see where you adjust the clutch on that threaded shaft, but there was no way i could have loosened the nut on the shaft without taking the master cylinder off the firewall. I took the pin out and disconnected the shaft from the clutch pedal, but couldnt get to that nut. Pisses me off.

Also, ive got a squeak when i apply the clutch pedal; its coming from inside the bell housing. Im not really sure what to do.

Shaun.

[battery]

its quite easy to take the master cylinder out with a uni-joint and an extension.

i got the full adjustment out of mine but it still isn't enough!

[Shaun]

Which way did you move the nut to get greater movement of the clutch? Towards the front of the car or towards the rear?

Im pretty sure you move it towards the front; just checking.

Shaun.

Edited August 27, 2008 by Shaun

[soul-reaver]

I'm having the same problem with my R32.

The car has difficulties engage to second if the revs are not right.

when braking, if the gear is in 2nd or 1st, if I don't shift to neutral before a complete stop, it is very difficult to push out of gear in the last few meters before stopping. And even with the clutch fully disengaged, the revs drops and almost stalls when coming to a stop with gear in 2nd or 1st, but once the car is stationary, there is no problem moving in or out of gear.

So to me it definitely feels that the clutch is not disengaging correctly, I'll give the method shown here a try and see how the OP goes with his attempts.

[petethepom]

You can get replacement piston kits from nissan for the clutch master and slave cylinder. They are really cheap, about $70 for both and p*ss easy to fit. I took out the bundy pipe and that extra bit and replaced it with a single braided line between master and slave cylinder. Made a load of difference!

Dont know if you blokes need the extra bit of pipe cos I heard it was for hot climates.

[Shaun]

^^^^ Thats exactly what im having made up at the moment. Ill piss off the hard lines and replace it with a single braided line. I also bought a Nismo slave cylinder, so hopefully it might make a bit of difference. Im pretty sure you lose a bit of travel with the Nismo slave though, because of its larger diameter bore. Ive still got some adjustment on the master cylinder push rod though.

I dont really understand the hot climate thing, as there is no flow in the clutch line anyway, so no real cooling effect. Except for increased surface area maybe.

Edited September 6, 2008 by Shaun

[FTO]

If it was operating ok before the problem showed up, it can really be only one thing..air in the system. Trickle bleed the slave cylinder & see if you get the travel back.

Nismo cylinder will just give you a lighter pedal effort on heavy pressure plates due to the piston size..can't imagine any other advantage, could be wrong...guess the name's worth something.

BTW; adjusting the master cylinder operating rod isn't going to give you any more travel because your just changing the pedal to piston stop relationship...not increasing piston travel..well unless it's badly adjusted already. Should you lengthen it too much, with the pedal fully extended, you will just push the piston up the bore & close off the feed port from the reservoir...and if there's a bit of wear in the bore & you change the piston travel, it's going to start leaking.

I'd just kit both master/slave cyls & problem solved..better still get them fitted with stainless sleeves & they will last forever.

hope this helps...

Edited September 6, 2008 by FTO

[Shaun]

Thanks mate. I just installed the master cylinder with the braided line and Nismo slave. The pedal is definately lighter, which is good because it was too heavy before. I adjusted the position of the clutch pedal and its too high so ill put it back where it was.

The braided line thing is definately worth while, as its so easy to bleed the clutch now. I got mine made up for $60 from the local brake and clutch place; i couldnt spend $120 on one from UAS.

[pavel]

So did nismo slave solve the disengagement problem?

[Shaun]

I havent taken it off the stands yet; ive had the flu soooo bad this week, i havent really left the sofa.

The Nismo slave definately makes the pedal lighter (i reckon 30% lighter), but i did the braided line thing at the same time, so im not sure if thats had an effect on the feel either.

Ill take it for a spin tomorrow if its not raining up here.

Just a side note. Ive also had a really annoying squeek in the clutch fork inside my gearbox, so i took the rubber boot off and lubricated the little ball thing with an extended paddle pop stick and some bearing grease. Youve gotta be really careful not to get grease everywhere otherwise it might get on your clutch, but its so much nicer to push the clutch in now. A really worthwhile thing to do if your clutch squeeks inside the gearbox housing.

[Shaun]

So did nismo slave solve the disengagement problem?

Dammit, ive still got the clutch disengagement problem. Its only intermittant. It can only really be the clutch now i suppose.

[Beer Baron]

nismo slave most likely wouldn't fix disengagement problems as the nismo slave actually has short throw than a stocky.

most like the problem is one of 3. damaged/bent fork. damaged/broken bearing carier (sometimes the little ears snap), damaged or broken clutch cover/pressure plate. the bummer is that pretty much all means gearbox off to diagnose.

[Shaun]

nismo slave most likely wouldn't fix disengagement problems as the nismo slave actually has short throw than a stocky.

most like the problem is one of 3. damaged/bent fork. damaged/broken bearing carier (sometimes the little ears snap), damaged or broken clutch cover/pressure plate. the bummer is that pretty much all means gearbox off to diagnose.

Hey, i was just thinking about what you said could be the problem(s) above, and ive just changed my harmonic balancer to an ATI item. I was pretty paranoid about having the thing come off because ive heard so many stories about this happening, so i really leaned on the bolt when tightening it up. In order to stop the engine spinning when torquing the bolt up, i had the car in fourth gear and the handbrake on tight.

Could this have bent the fork or caused any of the damage you suggested above? Im not really sure if any of that hardware is in use when the clutch is not depressed.

It would explain a few things though.

Thanks,

Shaun.