Clutch slips when hot

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Clutch slips when hot

Postby naff_monk » 10 Feb 2018, 19:14

Hi All

Tried the usual googling but can't find the answer to this one so hoping someone can help.

Some background:

Clutch slips slightly when hot (usually when the turbo kicks in in 3rd-5th). It's had a new kit approx 600 miles ago when I had a second hand box put in, problem first appeared after a few hundred miles at high speed on the motorway but I can get it to do it after 10 mins at 60mph now.

My expectation was it was likely to either be adjustment of the hydraulics or contaminated clutch, hoping the former. I've never dropped a gearbox before but decided to have a crack at it as my local garriage seemed reluctant and I'm not too keen on paying piles of money on labour for a non working drivetrain and I wanted to rule out gearbox leakage. I got as far as removing the slave cylinder before I noticed an inspection hole in the bell housing, why had I not noticed that before! Decided to re-assemble, get it hot again and shove some clutch cleaner down there to see if that made any difference before going to the trouble of dismantling anything.

Now, to my question. On re-installing the slave cylinder, I noticed that the rod is protruding further than the start of the clutch lever swing. I could get it on by tightening the bolts but that will deffo disengage the clutch a little leaving me with negative free play which leads me to think that this may have been my problem all along? I'm thinking if I bolt the slave cylinder back down then open the filler cap under the dash, the fluid should rise as the diaphragm spring returns the lever back to it's natural position and with any luck I should be sorted. Does that sound right or have I missed something here?

Cheers
Laurence
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Re: Clutch slips when hot

Postby silverbullet » 10 Feb 2018, 20:11

The slave cylinder has a light spring inside, to keep the pushrod seated and prevent the release fork etc chattering when the clutch is engaged.
Its usual to have to shove the pushrod up into the slave just to get the bolts in and tightened.

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Re: Clutch slips when hot

Postby naff_monk » 10 Feb 2018, 20:57

Ah right, that explains that then. Back to the clutch cleaner idea then.

Any suggestions for things to look out for if/when I get the clutch apart would be helpful also :)

L


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Re: Clutch slips when hot

Postby Aidan » 11 Feb 2018, 10:11

215mm clutch is marginal with higher output engines with a TDi maybe 20k miles life rather than the 60k miles with the original 1.6 engine
which brand clutch was fitted, I have heard from reputable trader the supposed upgraded ones like Black Diamond have proved to be anything but, just a con.
I would always use a Sachs clutch if I could, the release bearing is the best and they tend to be proper new manufacture rather than refurbished or made in 2nd/3rd world countries with lower quality components
The inspection cover for the diesel timing mark hole is very important, mostly they are missing due to slack ignorant mechanics, allowing fuel oil, engine oil, coolant (depending on which your engine leaks - I have never seen a diesel engine that didn't leak one, mostly they seem to leak all three :lol: ) and road dirt and water to contaminate the clutch and corrode the release fork and especially the brass bush
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Re: Clutch slips when hot

Postby naff_monk » 11 Feb 2018, 15:55

Clutch was a sachs for a JX from ECP. Probably worth mentioning that the engine is an ABL but had a JX pump and turbo so is a JX in all but name. Interesting to hear about the black diamond clutches, at some point I'd like to swap to an AAZ/GTD pump and up the boost so was probably going to fit one. Might not bother now!

So I put everything back together and took it out for a spin. I've obviously managed to mess up re-installing the slave cylinder/linkage because the bite point is much sooner on the pedal now and the gear shift is crap. I'll worry about that later though because I got it hot and slipping again, pulled over and got my head in there. There was a wisp of smoke coming out of the hole, it smelt more burnt oil (slightly fishy) as opposed to burned rubber, sprayed liberal amounts of clutch cleaner down there and tried again, still slipping. Got home and got my finger in there, came out dirty/oily, flywheel temperature was comparable to the oil filter so I'm assuming clutch contamination now.

Looks like drop the box time, wish me luck :ok
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Re: Clutch slips when hot

Postby Aidan » 12 Feb 2018, 07:26

have you mixed up parts from two different slave cylinders by any chance, the pushrods on the FAG style and ATE style are different lengths
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Re: Clutch slips when hot

Postby silverbullet » 12 Feb 2018, 08:06

Crankshaft seal needs replacing?

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Re: Clutch slips when hot

Postby dave friday » 12 Feb 2018, 10:56

Fishy smell? My guess is Gear box oil ( was the spigot bearing fitted?)
Good luck.
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