Project 50: Bleeding BMW Brakes

[Wayne at Pelican Parts]

Got any questions on Project 50for your E36 or E30? Ask them here!

-Wayne

[kdc71726]

Hi,
I was reading somewhere someone was saying that for a manual transmission, you have to bleed the clutch as well. Any truth to this?

[Wapiennik]

You don't have to, but you should.

I haven't bled my brakes in a while, but I recently purchased the power bleeder shown in Wayne's book. I pumped it up to 15psi and released the bleeder nipple on my slave cylinder and a couple huge air bubbles shot out. When I tried my clutch, it was so smooth I almost thought it was broken

The reason you should bleed it, if you didn't know, is because your clutch uses the same fluid from the same reservoir as your brakes, and removing old brake fluid in your clutch line could help prevent contaminating freshly bled brake lines-I'm assuming.

[Yurick]

Agreed.

[Vintage914Racer]

I'll bite. I've been struggling on an e30 chumpcar candidate. Hard lines are clear, no restrictions in flex lines, MC is good as is prop valve and no ABS. No matter what I do I can't get more than a dribble to the rear calipers.

Could I be overlooking something? I've bled brakes on a bunch of cars and haven't had the troubles I have had with this one.

[Yurick]

I've seen this in my E30 rag-top. I had to disassemble the rear slave cylinder. There, I found crud blocking the brake fluid from flowing in order to bleed. While there, I went ahead and installed a slave cylinder rebuild kit.

[Wapiennik]

Power bleeder works pretty good for front brakes and clutch slave but is almost useless for bleeding the back; even at high psi.

Stick with buddy bleeding.

[Vintage914Racer]

Yeah, I agree that pressure bleeding didn't net a good result. I'm even having problems with a buddy. But I will try again...

[Yurick]

I bet you got a blockage inside the slave cylinder, like I had. You will likely find it in the area of the bleeding nipple inside the cylinder.