engine and drivetrain Replacing Clutch Master Cylinder

[Guest Anonymous]

URL: http://www.bmw2002faq.com/engine_and_drivetrain/pedal_box.html

What are the steps to replacing the clutch master cylinder? In the article about the pedal box (linked), Paul mentions that the CMC causes problems, but what are the specifics? Thanks for your help.

-steve '71 2002

[Guest Anonymous]

As Paul sez, pulling the CMC is a pain. It is bolted to the pedal box from the outside. What Paul is alluding to is the difficulty of removing and reinstalling the two bolts that hold the MC to the pedal box. The problem is that the when you loosen the nuts, the bolts will turn, making this a 2 person job. It is remotely possible to do the job if you use vice grips to clamp down on the bolt head.

Here were the basic steps for removal on my '73:

1. drain or remove brake fluid from the reservoir until the level of fluid is below the intake for the clutch fluid line.

2. remove the hydraulic line between the MC and slave cylinder; have someone pump the fluid out into a container.

3. pull the fluid line out of the top of the MC and move it to the side; it is friction fit into a rubber fitting at the top of the MC and will pull up and out. Even though you have pumped the fluid out of the MC, be prepared with a rag to catch the remaining fluid that will drain out of the line.

4. remove your gas pedal; pull the rug up over the pedals and remove the rubber insulation piece (this piece NLA, BTW, so be careful with it) that fits around the base of the pedals/opening of the pedal box and set it aside. Loosen the locking nut on the CMC actuator rod and disconnect it from the pedal.

5. Use a deep reach 13mm socket and remove the nuts on the two bolts holding the MC in place. This is the part where you will need a buddy anchoring the end of the bolts from underneath the car... an open end wrench works pretty well. Pull the CMC out from below.

6. Reinstallation is, more or less, the reverse of the above.

Chris B.

'73 ex-Malaga

[Guest Anonymous]

1. Before installing new M/C, check clearance of nut with body of M/C. A little judicious grinding on the outside of the M/C will make it much easier to slip the socket over the nut.

2. Install the fluid line into the M/C before putting it back in the car. You can lower the M/C, hanging from the pipe down thru the engine compartment from above. If you don't do it this way, you'll never get the pipe in once the M/C is installed. Then you'll have to unbolt the M/C again...

3. Be prepared to change the slave cylinder soon...a new M/C will generate more pressure and make an old slave cylinder leak.

Have fun (gotta do this myself soon...)

Mike

Nevada '69 (needs clutch hydraulics)

Sahara '73