Clutch Pedal on Floor - slave cylinder??

[Alex C]

In the last few weeks/months I've noticed that the bite point on the clutch is very low; almost on the floor.

Now (today) the clutch pedal doesn't want to return back up and doesn't appear to release the clutch as I have to wrestle it in and out of gear

I haven't had any clutch slip so I think the clutch itself is fine and suspect it's a hydraulic issue

I have been advised to look at the slave cylinder and was told its external, but I'm having trouble identifying it

The car is a 2001 S3 AMK with 6spd O2M DQB gearbox. Do the 6-speeds also have an external slave? Could it be the master cylinder instead?

 

[NHN]

My S3 apy suffered like some others from the pedal metal plate weld coming of, it's a stretch but has yours done the same, did you check if the piston is stuck down or the pedal part has also snapped like was known on the S3.

 

[MPH]

In the last few weeks/months I've noticed that the bite point on the clutch is very low; almost on the floor.

Now (today) the clutch pedal doesn't want to return back up and doesn't appear to release the clutch as I have to wrestle it in and out of gear

I haven't had any clutch slip so I think the clutch itself is fine and suspect it's a hydraulic issue

I have been advised to look at the slave cylinder and was told its external, but I'm having trouble identifying it

The car is a 2001 S3 AMK with 6spd O2M DQB gearbox. Do the 6-speeds also have an external slave? Could it be the master cylinder instead?

It's in the engine bay gearbox side if I recall correctly

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[Ian W]

The slave cylinder is inside the gearbox so it is a box off job to replace.

Often you will see fluid dripping from the bellhousing it if has failed (though I didn't on my current one).

 

[Alex C]

Thanks all

@NHN I've had that clutch pedal failure before; it went with quite a crack and there were bits of metal/plastic left in the footwell. There was no sudden failure like that this time so I don't believe that's the issue.

@MPH @Ian W I googled 'Audi S3 8L' clutch kit over the weekend and could see a concentric slave cylinder included in the kit; so yeah looks like it's a gearbox off job if it is the slave cylinder...

 

[MPH]

Take a look here in PDF for more information https://www.audi-sport.net/xf/resources/categories/5/ https://www.audi-sport.net/xf/threads/56785/

 

[tcg]

When my clutch pedal went to the floor, it was the master cylinder that was knackered...inside the engine bay, might be worth checking that...

Stop the clock...Start the thread-My baby is home

Final upgrade for my RNS-E today, adding bluetooth music streaming from the phone. I bought a gadget from Ebay that plugs into the back of the radio, advertised for concert/chorus/symphony radio's...

www.audi-sport.net

 

[Ian W]

Thanks all

@NHN I've had that clutch pedal failure before; it went with quite a crack and there were bits of metal/plastic left in the footwell. There was no sudden failure like that this time so I don't believe that's the issue.

@MPH @Ian W I googled 'Audi S3 8L' clutch kit over the weekend and could see a concentric slave cylinder included in the kit; so yeah looks like it's a gearbox off job if it is the slave cylinder...

Yep, I have at separate times completed the job myself (horrible) and paid for it (expensive).

Neither option is great tbh and IMO it is the one major weak point of these cars with having the slave inaccessible without removing the box.

 

[Alex C]

@tcg thanks, yeah that's first thing I need to do really; find out whether its slave or master; hopefully the master

and if it's salve it would be silly not to then do clutch/flywheel...... and given the subframe is dropped it'll need a four wheel re-alignment in which case then it would be silly not to do the cv boot, broken coil spring, and the top mounts beforehand...

I've still got to get the blue bumper painted red after a minor crash a few weeks ago

and drivers side jacking point welded

...MOT end of month

 

[Alex C]

I clamped the hose to the slave cylinder and the clutch pedal was solid as a rock so the master cylinder is fine

Strange thing though is that now after taking the clamp off the clutch pedal returns to the top and I can change gear without having to wrestle it in and out - bite point is still very low. Only rolled it forward and back 20 yards though

 

[MPH]

I clamped the hose to the slave cylinder and the clutch pedal was solid as a rock so the master cylinder is fine

Strange thing though is that now after taking the clamp off the clutch pedal returns to the top and I can change gear without having to wrestle it in and out - bite point is still very low. Only rolled it forward and back 20 yards though

Check for an air leak would be a good move forward

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[Alex C]

OK; I clamped the flexible line just before the bleeder connection (#11 on page 19 of your gearbox manual) so it should be good all the way from the master cylinder to that point given the clutch pedal was rock solid leaving only the bleeder connection itself to be a potential source of an air leak. If a leak is on the other side of the bleeder connection then it's gearbox off anyway.

Might be worth bleeding the line...

 

[Alex C]

update:

Had the clutch fluid bled through, the garage was worried about shearing the bleed nipples on the calipers so didn't flush the brakes through.

Bite point on the clutch was much better; higher than it was. I took it out yesterday for a test run, felt good until I gave it full beans up a steep hill - clutch slip

so likely slave cylinder is leaking over the friction plate

 

[MPH]

Sounds like you probably have a diagnosis that is somewhat annoying at best but now positive and moving forward (words of encouragement) good luck keep us updated all the best @MPH