Clutch pedal springs - Master Cylinder operation

[tobodestroyer]

Hi,

I removed the tray from under the driver's side dash so that I could carry out the k-pin mod on the light-check relay and this bit fell out...



Can anyone identify it? It looks as though the spring in it has broken... just what the hell is it?

Tobo

[Nuvo]

It looks like the clutch pedal return spring.

[Jamo]

It looks like the clutch pedal return spring.

[s2_bo]

Yes, you dont want to go for a drive with out that part fitted...

[tobodestroyer]

Yes, you dont want to go for a drive with out that part fitted...

Strange, my clutch pedal returns just fine. Is there a diagram as to where it should fit? I have a feeling that it's probably been replaced and some one has left the old one rattling around under the dash.

[s2_bo]

Ahh, that makes sense.

[AndyP]

Strange, my clutch pedal returns just fine. Is there a diagram as to where it should fit? I have a feeling that it's probably been replaced and some one has left the old one rattling around under the dash.

They are known to just fall off, if your search you'll find numerous similar posts with people asking 'what is this? I just found it in the footwell!'

[Robatron]

Does anyone have a part number for this? A couple of weeks ago I found mine rattling around in the footwell but much like the OP my clutch feels perfectly normal.

[Flat on my back]

.

Here you go...just pick the right one.

[Robatron]

Thanks!

[tobodestroyer]

I looked under the dash and upwards to the top of the clutch pedal. OMFG - how the hell do you get in there to fit a replacement?

[Flat on my back]

.

Think when i had this trouble i managed to tie-wrap the 'things' closed a bit then fitted it in position and pressed the pedal to then hold it...then cut the wraps.

Also helps to have small girly hands...and that's the only small bit of me...

[Fat Audi 80]

Help!

Can anyone confirm how these springs are supposed to work???

I am still trying to get to the bottom of my intermittent clutch pedal problems.

Sometimes the pedal works fine, sometimes it gets stuch on the floor. When I had a look underneath at the weekend, I have two spring pressing on the back of the pedal.

When I disconnected the master cylinder rod the following happened:

For the first half of the travel, the springs force the pedal back up, but once you get over half way they pull it down to the floor. Surely you want the pedal to be springing back ALL the time. Does the clutch pedal rely on the springs of the clutch itself to bring the pedal back up???

On the same note, how do you adjust the master cylinder clamp. (Can you?) I could see a small piece of studding before the clamp that fits onto to the back of the clutch pedal, but could not undo the 11mm nut, and could not see how that would adjust it anyway.

Advice welcome....

Cheers.

Steve.

[johne]

Can anyone confirm how these springs are supposed to work???

I am still trying to get to the bottom of my intermittent clutch pedal problems.

Sometimes the pedal works fine, sometimes it gets stuch on the floor. When I had a look underneath at the weekend, I have two spring pressing on the back of the pedal.

When I disconnected the master cylinder rod the following happened:

For the first half of the travel, the springs force the pedal back up, but once you get over half way they pull it down to the floor. Surely you want the pedal to be springing back ALL the time. Does the clutch pedal rely on the springs of the clutch itself to bring the pedal back up???

On the same note, how do you adjust the master cylinder clamp. (Can you?) I could see a small piece of studding before the clamp that fits onto to the back of the clutch pedal, but could not undo the 11mm nut, and could not see how that would adjust it anyway.

Advice welcome....

Cheers.

Steve.

The pressure plate in our cars requires a powerful spring to ensure the clutch can transmit the torque without slipping. Powerful pressure plate spring means high pedal pressure. It is the pressure plate spring that - via the hydraulic fluid - is pushing the pedal back up when you take your foot off. The helper spring(s) behind the clutch pedal absorb some of the energy from the pressure plate plate spring pushing the pedal up so the next time you push the clutch pedal down you get some help from the helper springs and so the load on your foot is reduced. That's why if you have no clutch connected or a fault in your hydraulic circuit and you push on the pedal it goes rapidly to the floor as the helper springs push it down and the pedal stays there.

There is a subtlety that the helper springs are mounted in an over centre way so that as the pedal reaches the very top of its travel the helper springs flip over to work the other way and hold the pedal up - but only with a little bit of pressure and only at the very last part of the travel. This is needed otherwise the helper springs would always be pushing the release bearing on the pressure plate and doing the equivalent of riding the clutch even with your foot fully off.

As for adjustment, the clevis is threaded so you can release the 11mm nut and rotate the pushrod to adjust the distance (or disconnect the clevis and turn it on the thread). See attached picture. According to my Bentley the distance from the centreline of the clevis pin to the surface the master cylinder sits on the mounting bracket should be 116.0 + 0.2mm. This is for the regular coupe but I see no reason why S2 or RS2 should be different but I can't confirm that. I've set my car to this distance but then I've also lost two pressure plates

Oh and BTW it follows from this that it doesn't matter a damm if these helper springs have fallen out or are missing, the only difference is that your left leg will have to do more work. The clutch will work just the same.

John

[Fat Audi 80]

John,

That is perfect! At least I know what I am trying to do now, and the spring operation makes sense too.

Many thanks, I will take another look....

Cheers,

Steve.