I've had my 6er in the garage for over a month now with a clutch replacement. Mostly just haven't had the time to work on it. Maybe an hour here and there. Now that the tranny is back in and ready to go, I'm having a bear of a time with the master cyliner. When I put the slave back in, I had to compress the plunger, but didn't realize that the clutch pedal was also on the floor. So I had a situation where both cylinders were at the tube end of their cylinders and no fluid in the system. Now I can't seem to get the master to pull back out so it will fill with fluid. Isn't there supposed to be a spring in the bottom of the master, to push the piston back out? Mine does not have a spring in it. The rod keeps pulling out of the piston and the piston seems to stick at the bottom of the cylinder. The cylinder looks to be in good condition, in fact it looks like it has been replaced in the relatively recent past. How can I deal with this problem.

Second Item: The gravity feed from the the brake res where it connects to the master cylinder had at one time a plastic 45 degree tube that went from the gravity tube into a grommet in the master cylinder. This plastic piece failed miserably about six months ago (not pretty). Knowing that most plastics don't do well with brake fluid, I tried to fashion a replacement from a brass hydraulic fitting, but am having trouble getting it to seal. Has anyone had to make a replacement for this part? Or is there a replacement part I can buy somewhere?

As always, thanks for all your help guys.

on roadfly they keep refering to a website 'real oem' that has diagrams and someone recently posted that plastic piece is replacable after i responded to a post to be careful in that area.is the pedal stuck,or just no pressure to hold it extended?i had to bleed mine at the slave cylinder with it unbolted from the bell housing because the pedal just fell to the floor.i had a hose connected to the bleeder and would open it when pushing the plunger in and close the bleeder when the plunger came back out.if the pedal is not jammed,prop it to it's position and try bleeding at the slave.

Thanks for the tip on realoem.com, great diagrams. That's more documentation than I've had for this car.

Bleeding from the slave I suppose could work to get some fluid into the system, I haven't tried that yet. The pedel is free, so is the cylinder, I was just surprised when I had the piston blown out and there wasn't a spring inside. Every master I've ever taken apart in the past had such a spring and I assumed that this one should as well. I have found many areas where whomever worked on this machine before had taken a few shortcuts and wanted to know if this was another. I've never seen a rebuild kit for them, that spring would be a part of a rebuild kit.

I guess for the feed tube connection the plastic part must be workable, I just have never seen plastic hold up well when brake fluid is involved. But if the last one held up for 20 years, that's good enough for me. The one that broke was pretty badly melted. Sounds like a trip to the $tealer for me.

remember on my 1st one,the plastic nipple was broken and the PO just kept adding fluid,saturating the carpet and floorboard.i didn't know it was replacable and put in a new master cyl.

Yes the plastic fitting is replacable, picked one up from the $tealer for .83. Now that I've got it all back together, I can't get the pressure to pick up. Realizing that I've had the whole system apart, I can imagine that there is mostly air in the system all the way from the res to the slave. What is the best way to get the system to pressure up? I don't have a power bleeder, but may have to get one as I want this beast on the road again asap. Pumpng and bleeding the system is not seeming to build up any pressure, I've gone through the process at least 100 times. I worked on this yesterday, and decided that maybe it just needed to gravity feed for a day or so to let fluid displace some of the air in the system.

More than a little frustrated. Any suggestions? Thanks.

mike,did you get the hydraulics sorted out yet?you mentioned that the plunger came out.

We recently replaced the clutch assembly on my son's E24. We replaced the slave cylinder as a precaution and had similar difficulty getting the pedal (and master ) to actuate the salve.

did a search in the roadfly archives and found a bunch of similar posts.

turns out, once you have bled what you can via gravity, close the slave cylinder nipple and remove the slave cylinder, leaving the line attached.

Do NOT allow anyone near the clutch pedal ! Do NOT push the clutch pedal while the slave is removed from the bell housing.

once the slave has been removed, slowly push the rod in fully and allow it to extend. Repeat this several times. Re-install the slave cylinder, and you should have a good pedal, we did. Any remaining air will be pushed back to the reservoir.

good luck !

Brad
1979 635CSi
1981 745i
1991 M5
1992 735i

Holy Sh##! I've got to admit this one just about got me out of the car retoration project. After changing out the clutch (which I pretty much concluded was relatively OK), then the master cylinder (which was toast), and still not having enough pressure. I'm contorted under the dash, which at 6"4" is quite a trick, I notice that as I'm moving the clutch pedal up and down, the whole support member holding the dash, steering column, and pedals is flexing a good 2-3 inches. I grab a flashlight and climb in further to find that the bracket is ripped completely through. This is the bracket that holds the pedals, steering column, master cylinder, dash, etc. I was acutally surprised at how easy it came out once you drop everything down (Ok, I did have some adrenaline running at that point). I had a friend weld it back together and put it back in (which took considerably longer than pulling it out). This clutch is soooo smooth it's scary.

My conclusion was that this tear had been the culprit all along. Probably wasting the master cylinder because it would not operate in-line. But now I've got a brand new clutch & master and the thing fires down the highway. Ok, I'll keep playing with it for awhile longer.