New Sachs Clutch is slipping!

[GTiAnniversaryMan]

Just accidentally made it do it in 3rd at 2500 rpm. Not good.

[AudiA8Quattro]

I'm confused.
Why can't you separate the parts?
The flywheel bolts onto the crank, the pressure plate bolts to this, with the friction disc in between. The pressure plate bolts are tightened once the friction disc is centred.
Once it's all on, the gearbox is on, the hydraulics are connected, the clutch will self adjust when you operate the pedal.
Or am i missing something here?
If it is corrected fitted, then the parts must be faulty...

[GTiAnniversaryMan]

I'm confused.
Why can't you separate the parts?
The flywheel bolts onto the crank, the pressure plate bolts to this, with the friction disc in between. The pressure plate bolts are tightened once the friction disc is centred.
Once it's all on, the gearbox is on, the hydraulics are connected, the clutch will self adjust when you operate the pedal.
Or am i missing something here?
If it is corrected fitted, then the parts must be faulty...

You can separate them, but the self adjusting mechanism reads that as the pressure plate wearing down and the adjusters go to full to compensate as there is nothing now resisting them. Apparently resetting requires a special tool to put them back to zero adjustment. In other words they only naturally adjust one way. It's quite a complicated mechanism which inoves springs and a series of paired wedges. I believe there mght be some kind of ratchet invoved so that they don't adjust backwards. You wouldn't want them doing that as each time you operated the clutch they would be constantly adjusting back and forth.

Sachs actually recommend the use of a special installation tool on all self adjusting clutches to pre load the spring fingers until the pressure plate is bolted onto the DMF. Sic: "Failure to use this can make the self adjusters inoperable!"  Most people don't use one. Instead they tighten up the six stretch bolts a turn at a time. See this video: http://www.youtube.com/watch?v=Tp5KeAQntGM&feature=related

Given that they only adjust one way (in operation) my mechanic is not convinced that the adjusters will have 'reset' themselves. That means the clutch thinks it has a much thinner friction plate in it than it actually has. In theory this would mean that it is operating with a clutch plate which is significantly thickr than it is adjusted for. This will change the at rest position of the diaphragm spring and its fingers. This could either mean the spring is now unable to offer optimum clamping force, or could be causing the fingers to contact the face of the release bearing.

If anyone out there can confirm these technical detail (or correct them) I would be interested to hear.

This migh resolve the conundrum that the previous clutch (which I thought had done 80K) also slipped but is barely worn. It must have been replaced becuase it was not worn enough to have done 80K. I wonder if the friction plate was replaced but the original pressure plate was refitted without the self adjuster being reset? The car has a complete ASH from new and there is no record of a new clutch, so it was probably done on a budget.

[GTiAnniversaryMan]

Car went back into mechanic today. Waiting to see what he's found.

[GTiAnniversaryMan]

Car went back into mechanic this morning. He has found as follows:

No contamination - or leaks from crankshaft or hydraulics
Tiny amount of glazing to only a small part of friction material
Friction/clutch disc was in the right way
Self adjustment was even and OK
Pressure plate bolted up evenly

· SACHS Part Numbers
· Flywheel - 2294 000 113 / correct but three equidistant burns/hot spots on surface and a lot of play (not rotational)
· Pressure Plate - 883082 999788 / incorrect (3082000396) three burn marks/hot spots equidistant (matching flywheel)
· Organic Clutch Disc - 881864 999502 / incorrect (1864999980)
· Release Bearing - 3182 997 901 / can't find any numbers on it so assume it is correct for now.

Now waiting to hear from supplier.

[GTiAnniversaryMan]

The upshot is that Darkside are replacing the Flywheel and Pressure Plate plus 12 new bolts FOC (plus a small upgrade cost as I only paid for the standard Pressure Plate). The Organic disc is in good nick and shows almost no signs of wear so we are refitting that. It is the correct one it just comes from a different kit. Obviously I'd have liked something for the aditional labour cost but ho hum! Darkside have remained very concerned and approachable throughout and offered the deal without prompting.

So; with any luck, I will be able to report back next week that the clutch is refitted and working fine. Fingers crossed.

[GTiAnniversaryMan]

The car us back! Picked it up last night. 

Pedal feels firmer and there is a real feel to it. You can really tell where the bite pint is and there's a real sense if working against a spring. Took a little getting used to (stalled it twice!) but after thirty mins it was enjoyable to use.

Itvtajes a little more care feeding it in as it can easily snatch, and will probably be hard work in stop start traffic but not so much to concern me.

The BIG NEWS is that it doesn't slip at all. Obviously I am taking it steady for a bit to "bed it in" (no traffic light drag races etc.) but once in gear it just pulls. Tried all the things that caused slippage before and not a sign. 

In the end Darksude replaced the DMF, clutch cover and organic disc. It's cost me the labour to refit but my mechanic will do a deal on that. So EVENTUALLY I've got what I wanted. Very happy. My opinion of the Sachs product is restored. Well done to Darkside for their no quibble service. 

I think I'll take my mechanics advice and go back to R-Tech to have them adjust the remap to make the power feed in more progressive. The clutch us handling it now but it was useful to have him drive it and feed back to me. The remap they did on my Anni was very nice and the Audi is all a bit "sudden"!

Thanks to all who have offered advice and sympathy. 

[AudiA8Quattro]

So the clutch was wrong/faulty?

[GTiAnniversaryMan]

So the clutch was wrong/faulty?

A bit if both I think. Should have been an updated clutch cover not standard. In addition the flywheel seems to have a bit too much play and some high spots.

[AudiA8Quattro]

Glad you got it sorted.
I've never used any special tools except a disc centering tool when doing clutches, and never had a problem.
It did sound like a problem with the pressure plate.
You said the friction disc was the wrong part? maybe it was slightly thinner?