New Clutch Problems!

[RoVer™]

Hey guys, quite new to the Skyline scene - and it has been an absolute nightmare so far.

Bought the car which is a '96 Skyline GTS25T Series 2, stock with a brand new Exedy clutch, fitted by the previous owner. All sweet and well, until A 35C day comes along and the clutch starts slipping. Was on the freeway, in 5th gear and gave it less than half throttle to overtake, it slipped. In first to third it's almost unnoticable, on cold days it never happens. Over the next hot days it got very bad, until the clutch and fork gave in. Took the car to the mechanics, changed the clutch over to a Exedy 'Tuff' clutch (heavy duty) in a kit ofcourse, got a new fork aswell. All and sweet and well, until a 36C day a couple of days ago, where the clutch, in 5th on the freeway and it fkn slipped! Rang the mechanic, told me he's never come across this problem before and will check it out when he comes back from his holidays. He did tell me that he re-used the fluid which was some special oil (Redline I believe), because it was still new and better then the standard fluid he normally uses. Flywheel is perfect. I'm thinking this Redline fluid is thin to begin with, and is becoming too thin on hot days, causing bad lubrication in the gearbox causing the clutch to overheat (I think there was a burning smell). The car has done 128,xxx kms. I'll be changing the gearbox fluid after new year, hoping it'll solve the problem. Anyone experienced something similar to this before?

Also, yesterday the car stalled instantly while cruising at 60, turned it back on and the ABS light lit up on the dash. Quickly pulled over, in a few seconds of idling the brake pedal started going crazy then the ABS light turned back off... Drove back home with a sound appearing from the brake pads as if they're worn which there not. Drove the car next day and everything seems fine, would anyone have a clue what this couldv'e been about?...

Turbo also blew last week, swapped it over with an R34 turbo and intercooler. Am having bad luck with this one!

Any help is appreciated. Thanks.

[blind_elk]

Doubt your clutch slip problems are related to the gearbox oil - save your money.

Is there any freeplay in the clutch fork when the clutch pedal is up (clutch engaged)?

The ABS light probably came on because you (re-)started the engine while the car was moving. And the brake pad wear markers tend to leave a considerable amount of material on the pad.

[RoVer™]

Doubt your clutch slip problems are related to the gearbox oil - save your money.

Is there any freeplay in the clutch fork when the clutch pedal is up (clutch engaged)?

The ABS light probably came on because you (re-)started the engine while the car was moving. And the brake pad wear markers tend to leave a considerable amount of material on the pad.

No, not at all, quite the opposite actually. When the clutch slips the pedal becomes so much harder, not even say a mm of of freeplay. Any ideas?

[blind_elk]

Adjust the pushrod at the clutch pedal.

[RoVer™]

Adjust the pushrod at the clutch pedal.

On cold days, the clutch pedal is fine. On hot days, the clutch gets VERY stiff and starts to slip in high gears. Any ideas?

Edited December 27, 2009 by RoVer™

[RoVer™]

Could it be possible that there is oil leaking into the clutch, causing it to slip? leaking crankshaft seal springs to mind? Any input is appreciated.

[steve12]

You should first increase freeplay on clutch pedal by 10mm and see what happens on hot days. If same problem you may need the flywheel machined.

[RoVer™]

Increased pedal length to about 20mm-30mm, 10mm still had zero free play... Clutch pedal has freeplay now and feels lighter than before, even after abit of a push. Thursday is going to be 34+C, can test it out for real results then. If this was the cause of the slippage all along I'd be wrapped bit shattered also. $2000+ fk up... Thanks for all the input so far guys.

[BASHO]

just watchin.

[mad082]

could it be possible that the fluid in the clutch line is suffering from the heat and expanding and disengaging the clutch causing the slip?

[RoVer™]

could it be possible that the fluid in the clutch line is suffering from the heat and expanding and disengaging the clutch causing the slip?

Thats what made sense to me, blind_elk seems to be confident that this isn't the case though. I'll find out soon.

Edited December 29, 2009 by RoVer™

[mad082]

i see what blind_elk said above and i agree with him, however i'm not talking about the gearbox oil. the clutch isn't a cable clutch in the r33 skylines it is a hydraulic clutch line, so it is full of fluid which has nothing to do with the oil in the gearbox.

the clutch plate itself has no oil around it, otherwise it would slip and you would go nowhere. the oil in the gearbox has no bearing on the clutch itself. the only way that it could cause any slipping is if it was stupidly thick when it was hot and was basically like tar and making the cogs stick together more than what the clutch was able to turn, or it was so thin that the cogs get as hot as hell that they expand and bind up, however both of these would cause the car to slow down dramatically when you lift off or push the clutch in. also this would have no effect on the weight of the pedal.

my money is on there being an issue with the clutch line rather than anything in the gearbox

[Simon-S14]

its the master cyln...bin it and get a new one.

my 32 had this issue for AGES, no one could figure it out. after driving it for a few hours everything heated up and the clutch peddle became rock hard and the clutch peddle engagement point was right at the top. tried adjusting it and so forth but this made no difference at all. So i figured its got to do with the hydraulic fluid expanding, normally theres a port in the MC to allow for it (as the peddle engagement point should be the same no matter what the temp) and i stripped mine down and cleaned it out... it was blocked with some crap and put it back in and still didnt work.

so i got a new one and all is sweet now.

[RoVer™]

35C and the clutch didn't slip even under extreme force, now I'm quite confident the pedal was always abit pressed causing the clutch to be slightly disengaged, constantly. This 'small' problem binned 2 clutches, both being Exedy, 1 fork and will be giving my brand new heavy duty clutch an earlier retirement for sure. :sigh:. Props goes to blind_elk for suggesting the fix! Cheers for all the help guys.

[Simon-S14]

find a new mechanic. thats all i'll say

[steve12]

My car has 15mm of free play on cold start. After 5min of driving the free play is around 5mm?? Not sure why this is so but I think it is to do with the master cylinder O-rings or some sort of clearance issue with aging or something else. Anyway, if there was only 5mm of free play when cold then you will get partial clutch disengagement when car is running for a while or warms up.

Anywho, you're mechanic should have checked this and should have also noticed the clutch was ok when removed.

Funny how a bit of knowledge can save a lot of time and money.

[RoVer™]

Yeah, when he put the clutch in which was a cold day there was free-play even though it wasn't adjusted. The clutch becomes more sensitive to disengagement on hot days (read: 35C+) so I'm thinking my master cylinder might be on it's way out soon. We'll see.

[RoVer™]

Is it normal for the car not to boost like usual on hot days? (38C today!) It's usually boosting between 11-12psi, today it won't boost over 9-9.5psi, even after adjustment at the (turbotech) bleed valve. I did find the bleed valve loose this morning though. Tightened it back up, but minor difference. Hot day causing this boost drop? Probably helps to mention: stock R34 side mount, and R34 turbo. Thanks guys.

Edited December 31, 2009 by RoVer™

[Simon-S14]

yeah your always going to suffer loss of power on hot days, i wouldnt even be boosting it in that kind of weather