Brake fluid leaking from bottom of transmission bell housing (x-posted from S&B)

Whig Bong · 01-15-2013, 06:00 PM

So the other night I was driving home and my clutch pedal went out. I've had my master cylinder and my slave cylinder go out on my E30 before and I knew what it felt like so I decided to tow the car home and replace the slave cylinder. Got the new slave cylinder installed in about an hour and tried to bleed it. Only problem was when we added brake fluid to the reservoir it wouldnt hold the fluid. I check for any holes in the reservoir and couldnt find any. Then we pushed on the break pedal to see if there was a leak in the master. A ton of brake fluid started dripping from the transmission access panel and I got underneath and all I could see was fluid leaking from the bell housing. I know the brake lines that go over to the DSC unit run over the top of that section but can brake pipe even leak like that?

Thanks in advance,
Whig Bong

TL;DR: when I press brake pedal fluid leaks from bottom of bell housing. Think it has to do with DSC

teamdfl · 01-17-2013, 09:10 AM

The slave is leaking fluid into the bellhousing. If the slave was not properly installed with its pushrod on the release fork, you pushed the slave cylinder piston out of its bore. Get another Slave cylinder.

Whig Bong · 01-21-2013, 10:13 AM

Took the slave cylinder off and this was exactly the problem. Thanks for the help. Any tips for making sure this doesn't happen when I put another new one on?

teamdfl · 01-25-2013, 09:19 AM

It's been a while since I replaced one on an E46 so I don't remember any tricks or problems. In general, I bleed BMW slave cylinders by hand while under the car. With the slave hooked up to its hose but not installed in the trans, orient the slave so the hose fitting is up. Slowly push the pushrod in and let it extend a few dozen times. The air goes up and out the line and gravity pulls fluid down into the slave. Top off the brake fluid reservoir frequently to avoid pulling air into the line. When it feels and sounds like no more air is in the slave, bolt it in.

can0n4 · 01-25-2013, 02:37 PM

Quote:

Originally Posted by Whig Bong

Took the slave cylinder off and this was exactly the problem. Thanks for the help. Any tips for making sure this doesn't happen when I put another new one on?

just make sure it goes in straight. I did the same thing. Ten minutes later after I got the rod back in the slave cylinder I put it in straight and it was fine.

Whig Bong · 01-25-2013, 07:12 PM

Update: There turns out to be a lot more wrong with the system than I thought. Sent it to a local shop for further work

01-15-2013, 06:00 PM	#1
Whig Bong Registered User Join Date: Jan 2013 Location: Asheville, NC Posts: 4 My Ride: 2001 BMW 330ci View My Garage	Brake fluid leaking from bottom of transmission bell housing (x-posted from S&B) So the other night I was driving home and my clutch pedal went out. I've had my master cylinder and my slave cylinder go out on my E30 before and I knew what it felt like so I decided to tow the car home and replace the slave cylinder. Got the new slave cylinder installed in about an hour and tried to bleed it. Only problem was when we added brake fluid to the reservoir it wouldnt hold the fluid. I check for any holes in the reservoir and couldnt find any. Then we pushed on the break pedal to see if there was a leak in the master. A ton of brake fluid started dripping from the transmission access panel and I got underneath and all I could see was fluid leaking from the bell housing. I know the brake lines that go over to the DSC unit run over the top of that section but can brake pipe even leak like that? Thanks in advance, Whig Bong TL;DR: when I press brake pedal fluid leaks from bottom of bell housing. Think it has to do with DSC

01-17-2013, 09:10 AM	#2
teamdfl Lemony Fresh Join Date: Dec 1969 Location: Awesome, NJ Posts: 4,432 My Ride: 325it View My Garage	The slave is leaking fluid into the bellhousing. If the slave was not properly installed with its pushrod on the release fork, you pushed the slave cylinder piston out of its bore. Get another Slave cylinder. __________________ Mod the driver first. Participate in your local BMWCCA driving school. Have you joined BMWCCA yet? My Track Schedule The solution to the lack of headroom in the X6

01-25-2013, 09:19 AM	#4
teamdfl Lemony Fresh Join Date: Dec 1969 Location: Awesome, NJ Posts: 4,432 My Ride: 325it View My Garage	It's been a while since I replaced one on an E46 so I don't remember any tricks or problems. In general, I bleed BMW slave cylinders by hand while under the car. With the slave hooked up to its hose but not installed in the trans, orient the slave so the hose fitting is up. Slowly push the pushrod in and let it extend a few dozen times. The air goes up and out the line and gravity pulls fluid down into the slave. Top off the brake fluid reservoir frequently to avoid pulling air into the line. When it feels and sounds like no more air is in the slave, bolt it in. __________________ Mod the driver first. Participate in your local BMWCCA driving school. Have you joined BMWCCA yet? My Track Schedule The solution to the lack of headroom in the X6 Last edited by teamdfl; 01-25-2013 at 09:23 AM.

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01-21-2013, 10:13 AM	#3
Whig Bong Registered User Join Date: Jan 2013 Location: Asheville, NC Posts: 4 My Ride: 2001 BMW 330ci View My Garage	Took the slave cylinder off and this was exactly the problem. Thanks for the help. Any tips for making sure this doesn't happen when I put another new one on?

01-25-2013, 07:12 PM	#6
Whig Bong Registered User Join Date: Jan 2013 Location: Asheville, NC Posts: 4 My Ride: 2001 BMW 330ci View My Garage	Update: There turns out to be a lot more wrong with the system than I thought. Sent it to a local shop for further work