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Trevt
07-07-2010, 07:31 PM
Driving home from work tonight, waiting patiently at the lights, turn green and ...bang.... clutch pedal goes straight to the floor. No resistance in the pedal, no clutch and unable to select gear. :zx11:
Was able to start engine in 2nd and limp home (luckily only a mile).:D

My thinking is I have 3 likely causes:
- master cylinder;
- slave cylinder; or
- clutch/release arm.

:1zhelp: My dilemma is where do I start and how can I check each? If I can avoid it I don't want to pull everything off, so looking for any advice on most likely cause and which to pull off first.

I'm assuming I should be able to tell on master and slave if fluid pours out past the seals if I strip 'em.

Any easier ways or better ideas?:confused:

My beauty is a (high mileage - 194 000) 1994 A6 (C4) 2.6 Avant SE.

micheal balbrig
07-07-2010, 08:58 PM
Driving home from work tonight, waiting patiently at the lights, turn green and ...bang.... clutch pedal goes straight to the floor. No resistance in the pedal, no clutch and unable to select gear. :zx11:
Was able to start engine in 2nd and limp home (luckily only a mile).:D

My thinking is I have 3 likely causes:
- master cylinder;
- slave cylinder; or
- clutch/release arm.

:1zhelp: My dilemma is where do I start and how can I check each? If I can avoid it I don't want to pull everything off, so looking for any advice on most likely cause and which to pull off first.

I'm assuming I should be able to tell on master and slave if fluid pours out past the seals if I strip 'em.

Any easier ways or better ideas?:confused:

My beauty is a (high mileage - 194 000) 1994 A6 (C4) 2.6 Avant SE.

I Think you have covered most possible causes but try the simple ones first
like possibility of split/broken pipe going to slave cylinder. I think the fluid is shared on the brake reservoir and loss should show up quickly. I dont think
you will gain by stripping cylinders. Have a look for any leaks first.

Trevt
07-07-2010, 09:07 PM
Thanks, brake & clutch both share same fluid source. Checked for obvious leaks - both in footwell for master and underneath for slave. No sign of leaks or fluid level dropping in the reservoir :mad:

So thinking no easy option and looking to the release arm, a long day coming covered in grease and brake fluid coming up me thinks :(

micheal balbrig
07-07-2010, 09:53 PM
Thanks, brake & clutch both share same fluid source. Checked for obvious leaks - both in footwell for master and underneath for slave. No sign of leaks or fluid level dropping in the reservoir :mad:

So thinking no easy option and looking to the release arm, a long day coming covered in grease and brake fluid coming up me thinks :(
Here is a suggestion. (not tested) There is a short flexi piece of pipe going to slave cylinder,if this was squeezed tight and pedal pressed it might
confirm if master cylinder was developing pressure. If it is developing pressure then maybe swop slave cyl for a known good unit. There does not look like a lot to go wrong with the release arm. If you decide to remove g/box the pro??? cables are attached to top but there is a bracket and bolt
at side to release them,(that is if they are fitted ) Good luck

Peter D
08-07-2010, 10:05 AM
You would have to provide a gearbox code from the ID label in the spare wheel bay but in general the slave is mounted on the Gearbox but most of it is inside the box. First of all check the pedal box and ensure the clevis pin is in thew pedal/master cylinder. If that is operational then the remove the slave. If all looks well then I suspect the slave has worn a hole through the clutch release lever. Regards Peter

Trevt
09-07-2010, 11:54 AM
Thanks to all, started inside and the rod from clevis to master cylinder has snapped.
Now just need to find a new master cylinder. Seem to being offered aftermarket from local factors varying from 39 @ ecp up to 85 @ local factor. Are the aftermarket worth it (given age & mileage), anyone used any the would recommend or recoomend I don't go anywhere near?

Also can you bleed clutch manually or do I need to force fluid through with a pressure bleeder?

Dealer price is 95

Peter D
09-07-2010, 04:00 PM
I would take the ECP one. Bleed casn be done with the pedal but the only bleed nipple is on the back of the slave. Glad you found the problem. Check the clevis pin for uneven wear. Regards Peter

exaisle
29-08-2010, 05:56 PM
Curiously, I had exactly the same experience on Friday....also a mile from home. I'm wondering if they are designed to break when a certain distance from base? ;-)

For the previous few weeks I had occasionally had a slight difficulty in selecting 1st gear when stationary. It engaged when clutch was pressed a second time and I thought nothing of it. Obviously there was more to it.

There doesnt seem to be any obvious sign of leaks and the level in the reservoir appears ok. I await my mechanic's diagnosis with interest.

E.

2005 130bhp Tdi 75,000 miles