Burning clutch, clutch drag ?

[bobo83]

My 2zz donor car has a strange issue with the clutch: it burns at the slightest slippage.

I got the car without history and it had a slipping clutch. I changed the clutch myself (third time doing such a job, the other two went well). However, since I installed the new clutch, I can smell the clutch very very often when driving normally.

At first I thought it was okay given that new clutches have a break-in period, but it's been happening for the last 2000 miles. I drive plenty of other manual cars and all is good, so it's not user error.

The other problem that I have is that for the first few miles, it is hard to disengage first gear ?!? I have to add revs to be able to take it out of first. Some gear changes are also notchy. Engaging reverse always grinds a bit, even if I wait 5s after pressing in the clutch pedal.
Sometimes I have unstable idle that seems to stabilise when I press the clutch pedal.

I don't believe it is the gearbox that is at fault, it drove fine with the slipping clutch for the 50 miles or so I drove it. I bled the slave cylinder, adjusted the pedal ... nothing worked.

The flywheel has some burn marks from the slipping clutch, could this be the reason? Is it a bent clutch fork? Failing slave / master cylinder?

Any ideas are welcome.

This is what the flywheel looked like:

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[Carolyn]

It sounds like you got a defective clutch plate.

[bobo83]

Thanks Carolyn. I used an OEM-quality Aisin clutch but something must be defective.

Does the flywheel above look okay to you ? Don't really want to pay for a new one.

[Carolyn]

@bobo83

I've seen better.  A bit burnt but not grooved.  I'd de-glaze it with some 400 grit wet and dry.

Edit:  On second thoughts, 250 grit on a hard flat sanding block. 

If that doesn't improve it, you could take it off and take it to a machine shop that can surface grind it.

I don't think it would be the cause of the trouble getting gears.  That sounds more like a clutch plate with a bad spring resulting in uneven spring tension, so that it is neither exerting even pressure or able to properly come clear of the flywheel.

I've taken clutches out that had obviously uneven 'fingers' and they exhibited the same symptoms.

[bobo83]

@Carolyn, thank you for the advice, will try to sand the flywheel!

[Alex Knight]

Thanks Carolyn. I used an OEM-quality Aisin clutch but something must be defective.

A lot of fake parts on sale these days. Did you buy it from somewhere reputable?

[bobo83]

It was Autodoc, paid a premium for it!

I will remove the clutch next week, how could I test that the clutch itself is indeed the problem ?

[Carolyn]

It was Autodoc, paid a premium for it!

I will remove the clutch next week, how could I test that the clutch itself is indeed the problem ?

You might be able to see uneven fingers.  Otherwise it's pretty difficult.  You bought a good quality make of clutch, it's just that there's always a small chance of getting a mis-manufactured one.

The odds of it happening tweice are vanishingly small.

[bobo83]

Thank you Carolyn.

[bobo83]

I've remove the clutch, this is what the disc looks like:


There is uneven wear all around the inner edge.

Is this enough evidence that the clutch was faulty?
This patch seems to match the discoloration seen on the flywheel, could it be that ? But then why did it keep burning ?

[Carolyn]

I've remove the clutch, this is what the disc looks like:


There is uneven wear all around the inner edge.

Is this enough evidence that the clutch was faulty?
This patch seems to match the discoloration seen on the flywheel, could it be that ? But then why did it keep burning ?

What does the clutch pressure plate look like (both sides)?

[bobo83]

This is what the cover looks like. I compared it with another known-good clutch and they look very similar.

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You cannot view this attachment.

[Carolyn]

The fingers are all even...

I'm starting to blame the flywheel...

[bobo83]

The fingers are all even...

I'm starting to blame the flywheel...

I was thinking the same. I think I will get a new flywheel and clutch just to avoid having to drop the gearbox again in the very near future .

Thanks Carolyn.

[Alex Knight]

It was Autodoc, paid a premium for it!

I will remove the clutch next week, how could I test that the clutch itself is indeed the problem ?

I think Autodoc are a pile of pap.

[bobo83]

Final update: replacing both the flywheel and the clutch solved the problem.

I used a brand new OEM flywheel and a LuK clutch.

Thanks everyone for the help.

[Ardent]

Luk in mine. No complaints.