How to for Clutch slave and master cylinder replacement

Gmac · 25-02-21, 07:29 AM

Hi folks,

Haven’t dropped in for a while, but I’m looking for a how to guide, with pics would be good, for how to change out the slave and master cylinder on my rr urq. The pedal gave up the ghost end of last year and I’ve now got no clutch, bugger, and I’d like to get it on my 2-poster and get both changed out before April/May when the non salted roads are back!

I’ve got both cylinders waiting, what else will i need? Which fluid? Any nuts and bolts or pins that I’ll need to get?

TIA

mikes2 · 25-02-21, 02:09 PM

No picture guides from me but the slave is only held on by a single M8 bolt and 30 year corrosion. Easier if you shift the steering to the side. If you loosen the hose first, you can then undo the bolt, remove the slave and wind it off the hose

The MC - best guide for that is on Phil Payne's old site. I've heard it's a pain in the Ur but on the S2 it was fairly straightforwards.

Fluid is just dot 4 brake fluid

Gmac · 25-02-21, 07:12 PM

Quote:

Originally Posted by mikes2

No picture guides from me but the slave is only held on by a single M8 bolt and 30 year corrosion. Easier if you shift the steering to the side. If you loosen the hose first, you can then undo the bolt, remove the slave and wind it off the hose

The MC - best guide for that is on Phil Payne's old site. I've heard it's a pain in the Ur but on the S2 it was fairly straightforwards.

Fluid is just dot 4 brake fluid

Thanks Mike....What do you mean by shifting the steering to the side? I dont even know where the slave is! Haha..

tractor Dave · 25-02-21, 07:18 PM

Quote:

Originally Posted by Gmac

Thanks Mike....What do you mean by shifting the steering to the side? I dont even know where the slave is! Haha..

Slave is on the side of the gearbox. By moving the steering over it gives more room to work. You might have to reverse bleed to get all the air out. It's the only method I had success with on the S2. Apparently master on the Ur is a bit of a pig due to limited space so good luck.

Gmac · 26-02-21, 07:34 AM

Thanks, I’m sure it’ll become more obvious when i get it on the 2-poster. I think you mean turn the steering wheel one way to full lock so that it move the rack out of the way...?

tractor Dave · 26-02-21, 08:50 AM

Quote:

Originally Posted by Gmac

Thanks, I’m sure it’ll become more obvious when i get it on the 2-poster. I think you mean turn the steering wheel one way to full lock so that it move the rack out of the way...?

Yes, you will see when you turn it full lock.

Groundhog · 26-02-21, 12:05 PM

The slave is at the top of the gearbox not the side ( typo? ) yours will be retained by a bolt which is easier to deal with than the early ones that were held by a roll pin. As above loosen the pipe first and wind the cylinder off it - saves time.

The master is a fiddle to be sure. I always used to maintain that Audi took the heater box and clutch cylinder and then built the car around them! It is a lot easier on a left hand drive car in fairness so it’s just one of the many things that didn’t lend itself to be moved over without redesign. With respect to Phil Payne his instructions are complicated in the extreme and describes a lot of work that is not required. There is no need to remove the drivers seat or the steering wheel and switch gear let alone the throttle pedal. In the day I replaced, literally, dozens of these and never had need to destroy clips so that one confuses me. Generally speaking release the reservoir in the scuttle so the feed pipe can be pulled through a little. Remove the under dash and pedal trim. Remove the lower steering column (one bolt and slide it up and off). Remove bolts and nuts holding the pedal box in ( not forgetting the one hidden in the engine bay on the other side of the fire wall). The pedal box can then be pulled down enough to access the cylinder. Undo the pressure pipe, lever out the feed pipe (plenty of rags to catch fluid) two nuts and bolts and pull the cylinder of the actuating rod ( don’t remove the rod) if your new cylinder comes with a threaded rod ( the genuine ones did) then discard it.

As I said, in the past I have done dozens so I accept it’s easy for me to say but it’s not difficult so much as fiddly

Colin Aitchison · 26-02-21, 08:24 PM

Hi Gmac how is it going,
Great advice form the rest of the guys.
Slave cylinder is ok just a bit of a stretch.
Master cylinder, I would ask you to consider removing the pedal box and disconnecting the brake linkage and removing the pedal box from the car, removing the master cylinder and refitting it and then replace the pedal box, more advice, make sure the drivers side door is open fully before you lift the car on the two post lift as this will aid access to get into the foot well area, its just a bugger when the car is up in the air and need to come off the lift to open the door fully, after removing the under dash tray that has the ECU attached to it you will get a better view of the access problem, you may also need to remove the drivers seat, again for access.

spink · 27-02-21, 04:48 PM

it has been known for the slave to corrode itself to the gearbox so much that when its been persuaded out part of the gearbox cracks off,be careful as that will be a bad day

Gmac · 04-03-21, 07:18 PM

Quote:

Originally Posted by spink

it has been known for the slave to corrode itself to the gearbox so much that when its been persuaded out part of the gearbox cracks off,be careful as that will be a bad day

That would most definitely be a bad day!!

25-02-21, 02:09 PM	#2
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	No picture guides from me but the slave is only held on by a single M8 bolt and 30 year corrosion. Easier if you shift the steering to the side. If you loosen the hose first, you can then undo the bolt, remove the slave and wind it off the hose The MC - best guide for that is on Phil Payne's old site. I've heard it's a pain in the Ur but on the S2 it was fairly straightforwards. Fluid is just dot 4 brake fluid __________________ 1991 90 quattro 20v sport 1991 90 quattro

26-02-21, 07:34 AM	#5
Gmac Grown up member Classic Audi Club Member Join Date: Feb 2015 Location: Aberdeenshire Posts: 686	Thanks, I’m sure it’ll become more obvious when i get it on the 2-poster. I think you mean turn the steering wheel one way to full lock so that it move the rack out of the way...?

26-02-21, 12:05 PM	#7
Groundhog Grown up member Join Date: Nov 2009 Posts: 143	The slave is at the top of the gearbox not the side ( typo? ) yours will be retained by a bolt which is easier to deal with than the early ones that were held by a roll pin. As above loosen the pipe first and wind the cylinder off it - saves time. The master is a fiddle to be sure. I always used to maintain that Audi took the heater box and clutch cylinder and then built the car around them! It is a lot easier on a left hand drive car in fairness so it’s just one of the many things that didn’t lend itself to be moved over without redesign. With respect to Phil Payne his instructions are complicated in the extreme and describes a lot of work that is not required. There is no need to remove the drivers seat or the steering wheel and switch gear let alone the throttle pedal. In the day I replaced, literally, dozens of these and never had need to destroy clips so that one confuses me. Generally speaking release the reservoir in the scuttle so the feed pipe can be pulled through a little. Remove the under dash and pedal trim. Remove the lower steering column (one bolt and slide it up and off). Remove bolts and nuts holding the pedal box in ( not forgetting the one hidden in the engine bay on the other side of the fire wall). The pedal box can then be pulled down enough to access the cylinder. Undo the pressure pipe, lever out the feed pipe (plenty of rags to catch fluid) two nuts and bolts and pull the cylinder of the actuating rod ( don’t remove the rod) if your new cylinder comes with a threaded rod ( the genuine ones did) then discard it. As I said, in the past I have done dozens so I accept it’s easy for me to say but it’s not difficult so much as fiddly

26-02-21, 08:24 PM	#8
Colin Aitchison Senior Member Classic Audi Club Member Join Date: Dec 2013 Location: Back home in Tillicoultry Posts: 1,308	Hi Gmac how is it going, Great advice form the rest of the guys. Slave cylinder is ok just a bit of a stretch. Master cylinder, I would ask you to consider removing the pedal box and disconnecting the brake linkage and removing the pedal box from the car, removing the master cylinder and refitting it and then replace the pedal box, more advice, make sure the drivers side door is open fully before you lift the car on the two post lift as this will aid access to get into the foot well area, its just a bugger when the car is up in the air and need to come off the lift to open the door fully, after removing the under dash tray that has the ECU attached to it you will get a better view of the access problem, you may also need to remove the drivers seat, again for access.

27-02-21, 04:48 PM	#9
spink Senior Member Classic Audi Club Member Join Date: Dec 2007 Location: yorkshire Posts: 1,525	it has been known for the slave to corrode itself to the gearbox so much that when its been persuaded out part of the gearbox cracks off,be careful as that will be a bad day