<E30> clutch master and slave cylinder replacement (long)

[Evan Arnerich <arnerich@xxxxxxxxxxxxxxx>]

After losing the clutch master cylinder in my E30 325 (pedal went down,
didn't come back up), I ordered a new master and slave cylinder and set
out to do the replacement. Here it is:

Master Cylinder (MC):

1. Drain the fluid from the clutch system. I did this by running a hose
from the slave cylinder (SC) bleeder valve to a suitable container,
opening the bleed valve on the SC, and pumping the clutch pedal until no
more fluid came out.

2. Remove the MC. You need to disconnect the hydraulic hose that runs to
the SC. This was easier after removing the steering coupler that
connects the steering shaft to the steering rack.  Next, under the dash,
disconnect the clutch pedal from the MC. This is an eccentric 17mm bolt
with a 13mm nut. Once disconnected, the pedal will either go to the
floor or pop all the way up. If it goes up, it may bend the bracket
which holds the cruise control disengage switch, so keep it down. Now
remove the two 10mm bolts which hold the body of the MC to the firewall.
These are difficult to access, and you may need to manuver the clutch
pedal up and down to access them. Now pull the MC away from the
firewall, just enough to get your fingers in to remove the push-on fill
hose from the fluid reservoir. There should be no fluid in it since you
remembered to drain it, right? I put down some rags to catch drips, just
in case.

3. Installation is the reverse, except that installing blind bolts
always seems harder than removing them for some reason. Don't forget the
push-on hydraulic fill hose. The hydraulic connection forward of the
firewall is especially challenging. Adjust the pedal position with the
eccentric bolt until the pedal's resting position is ~10 in from the
firewall (per Bentley).

I wasn't done yet, as I'd been advised to also replace the SC. Here are
those steps:

1. You shouldn't need to drain the fluid from the whole system if you're
just doing the slave cylinder, but you'll lose more fluid on the floor
etc. if you don't, YMMV. Disconnect the hydraulic coupler (just below
the MC forward of the firewall).

2. Remove the two 13mm nuts that hold the SC to the trans. The top one
of these is not visible, and I needed about 18" of 3/8" extension and a
3/8" flex joint to get at it. The bottom bolt is no problem. The SC just
falls off once both nuts are off.

3. Installation is again, the reverse. You must install the hydraulic
hose prior to installation. A new one was included with the kit I got
from Steve D.  Remember to lube the end of the SC's push rod before
installing. For the top bolt, I put a little grease in a socket to
lightly hold the nut, then snaked the nut onto the stud with the long
extension and flex joint.  Put on the bottom nut and tighten both. Now
connect the hydraulic hose back to the MC.

4. Bleed the air from the system. Fill the reservoir (careful with that
brake fluid) and watch for the system to start filling itself (you can
see bubbles come up in the reservoir). Open the bleeder on the SC and
pump the clutch until fluid starts running out (into your container
through the hose like before). Close the bleeder and get a friend to
pump the clutch so you can get underneath and let the air out. It's just
like bleeding brakes, only the pedal doesn't come back off the floor
until you've got some of the air out of the system.

Don't forget to reinstall the steering coupler. Could make for an
interesting test drive.  ;^) Test drive and repeat 4 above until the
clutch works like it should.

BTW the new parts fixed the problem. I'm sure was glad it wasn't in the
clutch itself :). Parts cost was $105 from Steve D.  A local independent
garage wanted $330 for the job.

Next job is air conditioner that decided to puke its oil on the garage
floor the day before the clutch problem arose. When I get that one
fixed, what's next?

Evan

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