pete944

A while back (Nov. 2002) I did a write-up on changing and bleeding the clutch master & slave cylinders. I just finished this job on my S2 and I’d like to repost it here. There are a lot of us out there who ask a lot of questions about this one and are worried about doing it. It’s not a hard job. The toughest part is the extremely tight space around the clutch master cylinder.
If your clutch pedal goes to the floor and stays there or you see brake fluid leaking onto the carpet under the dash, you need to replace the clutch master cylinder and slave cylinder. It’s probably best to do them both together so you only have to do this job once.
You’ll need a new clutch master cylinder, a new slave cylinder and a 12” piece of blue brake line hose. Paragon Products usually has the best prices on these parts.
The only special tools you’ll need are a 3/8” universal joint for your ratchet, (If you don’t have one go and get one before you start) a Motive Power Bleeder or equivalent (you can do it without it but be prepared for hours of bleeding and major frustration), a turkey baster, and a set of flare nut wrenches. If you don't need to do this now, print it out anyway. You'll have to do it eventually.
Here goes:
1. DISCONNECT THE BATTERY!! This is important, you’ll be removing the starter and those wires are hot.
2. Go under the dash and disconnect the pushrod from the clutch pedal. There is a spring clip holding it on. Loosen the 13mm nut on the linkage and remove the brass piece that connects the rod to the pedal. You’ll need it later.
3. Move to the engine compartment and use the turkey baster and remove fluid from the brake reservoir until the level is below the blue braided line that goes to the clutch cylinder.
4. Cut the blue hose (you did buy a new one, didn’t you?) but be careful not to break or cut the nipple that it connects to on the brake reservoir.
5. Use a 12mm flare nut wrench and disconnect the line coming off the front of the clutch cylinder. This is a pain to get to but take your time and you’ll get it.
6. Remove the two 13mm nuts that bolt the clutch cylinder to the firewall. You’ll need the 3/8” u-joint here, it’s impossible without it. Remove the old cylinder.
7. Connect your new blue hose to the new clutch cylinder with a hose clamp and slide the new cylinder in place. Put the two 13mm nuts and washers on and tighten them down. Be careful not to drop the nuts, I use a magnet on my ratchet extension to keep the nuts in the socket.
8. Connect the pressure line to the front of the cylinder and tighten with the flare wrench.
9. Use the turkey baster and inject new brake fluid into the cylinder through the blue hose. Then connect the blue hose to the brake reservoir and secure with a hose clamp.
10. Jack up the car and set it on good, stable jack stands.
11. Disconnect the wires on the starter and remove the starter.
12. Just above where the starter was you’ll see the slave cylinder. Remove the line to it with the 12mm flare wrench.
13. Remove the two 13mm bolts and remove the slave.
14. Install the new slave cylinder and reconnect the hard line.
15. Attach a piece of clear tubing (the Motive bleeder comes with one) to the bleeder bolt on the slave and place the other end in a clear bottle or jar.
16. Go back to the engine compartment, connect the bleeder to the brake reservoir, pump the bleeder to 10psi and listen for air leaks. If you have one tighten it up now.
17. Release the pressure on the bleeder and fill it with clean brake fluid. Pump it up to 25psi and go back under the car.
18. Use a 7mm flare wrench and crack open the bleeder screw on the slave. You should get a nice spurt of fluid and air bubbles through the hose. Make sure that you don’t run the Motive bleeder dry. Repeat until you don’t see any more air bubbles, tighten the bleeder, remove the hose, put the rubber dust cap on the bleeder, and reinstall the starter.
19. Disconnect the pressure bleeder. You’ll have to use the turkey baster again to remove some of the excess fluid in the reservoir so it’s not above the fill line. Put the cap back on the reservoir, reconnect the battery, and you’re done under the hood.
20. Go back inside the car and reconnect the pushrod to the clutch pedal. Adjust the length of the rod until there’s 1/8” of free play before you feel resistance in the pedal.
21. Make sure the pedal feels right and you can shift easily with the clutch in. Test your brake pedal also before you start it up and road test.
22. Go have a beer, you did it!

There are other methods of doing this job but each time I've done it it's worked perfectly.

triscadek

Bump

IceShark

A couple additions. You can get at the two master cylinder hold down nuts with a 3/8" universal joint but it is much easier if you pick up a 1/4" drive. Gives you more room to play with. I've done it with both and trust me, 1/4" is a lot easier.

Stick a rag in the hole at the top of the bellhousing so you don't drop anything down in there, like one of the nuts.

The problem with bleeding is due to the poor construction layout of the slave. Air gets trapped at the top of the cylinder and the bleed nipple won't let it out very well. If you have the slave disconnected, hold it in a verticle position and fill it with fluid, connect things back up you can avoid the trapped air problem. Sort of messy so don't drop fluid in your eyes.

bloodraven

question...because i am an idiot...if I am looking from the top of my engine....how do I get to the master cylinder? Anything I have to remove? Just curious...cause I looked and couldn't see anything because of about 50 million pipes in the way...

pete944

From the front of the car it's just below and to the right of the brake booster. It's tough to get to, but it can be done. You have to have a 3/8" or 1/4" universal joint on your ratchet and extension.

GOBOGIE

Nice write up Pete!

Eric

raven,

Remove the anodized bracket holding those hoses, etc. in place--2 bolts right on top. Then, unplug the 2 small vac lines, and undo the hose clamp on the larger "T"hose--then you can access it. Be sure to remove the hardline prior to removing the cylinder form the firewall--makes it much easier--AND hook up the clutch pedal before securing the new cylinder to the firewall.

TestDriver

Hello,

First off, I'm a cheap bastard but I make up for it with some ability and an insatiable lust for tools (the cheapness thing repeats itself here too). So, is there a place that anyone here knows about where I can buy the wearing parts (usually rubber cups) for the master cylinder? Or, has someone used rubbers or complete cylinders from a different application?

Cheers.

TestDriver

Hello again,

Sorry about this. I did a search (usually a last resort for me) and found the information I was looking for in previous posts. Seems Partsamerica, NAPA and Carquest all carry this stuff.

Cheers.

Ramon

kennycoulter

have you done this to many DIFFERENT 944s? how much play does/should the clutch fork have if any?

pete944

I've done this on two different 944's. Both times with the exact same procedure and both with great results each time.
The pedal should have 1/8" of freeplay at the top of it's travel.

bloodraven

alright...hopefully finally going to do this...is there anyway to bleed without the 7mm flare nut wrench? No one around here has one that small...and I can't find any friends with one...can I use like an adjustable wrench or vise or something like that?

Bhj0887

Just use a 7mm 12 point wrench, just be careful not to strip the valve. There is no room for an adjustable wrench in there.

If your bleeding the clutch the old-fashioned way.Let it be know you to have to tilt the car down towards the driverside to allow fluid into the master cylinder.

brad-cam

Another addition - while replacing the clutch cylinders, you should also replace the line from the slave cylinder up to the engine compartment. These are only about $20 and I've heard of them failing. Might as well replace while you've got it apart.

bloodraven

ibought a hose that goes from the end of the master cylindre to god knows where....thought I needed it...heh...