Bleeding clutch cylinders

[JD4020]

Good morning,

I installed a new slave cylinder last night. And I cannot get system to pressure up. I used the bleed valve on slave cylinder to bleed out any air. Not sure if all air is out. It's a pain.

I got somebody to press down on clutch pedal with bleed valve open. Before releasing pedal I would close bleed. Take that about 10 times. No luck.

Next I got person to pump clutch about 10 times and hold it down. Next I would release any air with some fluid thru bleed. Before releasing pedal I would close bleed.

Next I removed slave cylinder and placed bleed upward and opened it. With my hand I pushed in pushrod several times. Reinstalled it, no luck.

Next sure what is wrong. Do I stay have air in the system.

Every time I push pedal down the fluid in reservoir increases slightly. Not sure if this should happen. I might increase 1/8 to 1/4 inch. Could the master cylinder not be working now. Bummer.

Does the master cylinder have a check valve in it. Could it be the problem.

The master cylinder was working fine before but now with new slave cylinder could the correct resistance be causing issue with master?

Do not want to pull master cylinder if its air in system.

What test can I do to prove its air or faulty master cylinder?

Thanks Larry

 

[Peter Coomaraswamy]

There is a thread in this, has to be bled from the bottom up or pulled down through the system. I cracked all the bleed screws, master and slave and let the fluid drain through the system overnight and that can work as well. Ideally it's best to bleed both before installing. Sounds like you're just pushing air around now.

 

[Cornishman]

Pressure bleeder

After I replaced the slave with a new one I just used a pressure bleeder. Attached the inlet air side of the bleeder to a bike tyre which I partly reduced the pressure first. Then opened bleeder valve on slave, watched a few bubbles come out and then closed it and detached bleeder. Vert straight forward and no clever science.
Since I bought a pressure bleeder I would not consider the pumping approach as the master cylinder piston moves further than normal in its bore and hence may damage itself in an old system that may be pitted or rusted, especially with brakes.

Don't know about the level increasing in the reservoir, this seems the wrong way around to me, I would expect a static level or a reduction.

Why did you I change the slave cylinder, perhaps it was not the issue and the master was the problem? What were the symptoms?

Is the slave cylinder actually pushing against anything, could that be wrong?

Good luck
C

 

[JD4020]

Clutch bleeding

The slave was leaking fluid and after inspection the cylinder wall was pitted and seal was worn and cracked.

It was working fine several months ago. And shifting in and out okay.

I'm worried the master cylinder is done. Not sure how to test.

And can I purchase a seal kit for it?

If not what master cylinder part number would work on these coupes.

It not like the 535i (the cylinder sit in engine compartment and not under dash)

Thanks Larry

 

[HB Chris]

Order an e9 master, you will get the e21,e23,e24 etc replacement.

 

[JD4020]

Master cylinder

Is it part number 21-52-1-156-004

Where would be the best place to order it.

 

[HB Chris]

Penske says 21521114539, $232 at Tomkinson. But your number 21521156004 is e21 and only $104. Maybe the original is available again? The e21 part requires some mods, I had to tap the firewall where there is a ridge in upper right corner for it to seat. See my pic, I think I cut the pipe and used an elbow and blue hose to fit the input, the angle is different.

 

[Stevehose]

Then when you bleed it again I also had success starting off with the gravity bleed like Peter C suggests

Penske says 21521114539, $232 at Tomkinson. But your number 21521156004 is e21 and only $104. Maybe the original is available again? The e21 part requires some mods, I had to tap the firewall where there is a ridge in upper right corner for it to seat. See my pic, I think I cut the pipe and used an elbow and blue hose to fit the input, the angle is different.

 

[JD4020]

Master Cylinder for Clutch

I cannot find part #21-52-1-114-539 for master cylinder.

Need some assistance.

Not sure if an aftermarket one is available.

If none are available which one will work.

Thanks for your help, Larry

 

[Stevehose]

Rebuild the one you have:

http://www.ebay.com/sch/i.html?_ftr...313&_nkw=bmw+3.0cs+clutch+master+fte&_sacat=0

 

[m5bb]

This goes back a little bit.

Is fluid coming out the slave when you try to bleed it or is it just bubbling?
Could be the supply line is sucking air, the hose has collapsed or is disconnected or the reservoir is not full enough to go out the hose to the clutch master?

Just a thought.................

 

[HB Chris]

I looked it up at Penske on this page:

http://www.penskeparts.com/DiagramsMain.aspx?vid=47811&rnd=03192010

Go to Clutch, page three I think.

 

[Peter Coomaraswamy]

JD, I think I have a new extra- send PM if you still need one.