Help! Bleeding brakes/clutch...now no clutch pressure!

[goinstrong]

Help! I was bleeding the brakes after putting new bushings in on the rear of the car. The lines had been disconnected. The brakes had air, but now are good. I should say that I started with a pressure bleeder, but went back to the old school way. The pressure was at 10-14 psi.

Then I went under the car, and bled the slave cylinder figuring if there was that much air in the lines, the slave probably had air in that line too.

Yes, there was a burst of air initially from the slave cylinder, but it won't go away, and the clutch pedal almost falls to the floor. I started the car in neutral to see if that would help, but no change. The car is up on 4 jack stands right now...

Is the slave cylinder bad? Or...is there a ton of air in the line? Do I need to re-bleed the brake lines? Thanks for your help!

Tim

[Adrian_Visser]

Just keep bleeding it dude.

Make sure that the reservoir is full of fluid, the clutch line connects a little way up the side of the reservoir so it could be that you let the fluid level get down too far and forced a whack of air into the clutch line.

If you are doing it manually you'll be fighting the air bubbles which want to float back up the line so the faster you do it the better.

[StereoInstaller1]

$15 and half an hour:







I need to stop by a tire shop and pick up an all-metal valve stem to mount in the bottle to allow bleed off. Makes for a damn quick fluid change...but I need to pick up a few feet of 1/4" clear tubing so I can put it on the floor instead of on the motor.

GL!

Luke

[goinstrong]

Thanks Adrian. I will give it a try tomorrow and post the results. Should I keep the bleeder open and pump like crazy with the hose in brake fluid, or keep opening and closing after the clutch is down to the floor?

Tim

[goinstrong]

StereoInstaller,

The pressure bleeder seemed to have an air bubble in it that I couldn't get rid of, so that is why my son and I decided to bleed the lines the old school way. Is there a tip for removing air from the line to the master cylinder reservoir from the pump? Thanks...

Tim

[02for2]

Power bleed - old school method on an old car is a sure way to blow the aged MC, Slave or caliper seals.

You just haven't gotten all the air out.

I usually figure 2 Ltrs. brake fluid to be sure I get all the air out.

Also, I usually power bleed from the caliper and/or Slave back to the MC - air naturally wants to rise, going the other way is 'unnatural'.

You'll need simple mod to the bleeder to get it on the bleed nipple and a Turkey Baster to continually remove excess fluid from the reservoir - a 2 man job.

Start furthest away from the MC and work your way towards it... but you already knew that.

Cheers!

[goinstrong]

Thanks O2for2...I LIKE the reverse bleed idea!
Tim

[StereoInstaller1]

Eh, I only do a couple pumps on that tank, ain't looking for 200PSI, so no issues on blowing seals...besides, if that POS $10 bug sprayer blew seals in my brake system, I am NOT gonna DRIVE on that shit, y'know?

Plus the idea is to flush the fluids without causing bubbles in the first place. I still do a manual "assisted" bleed afterwards, just because I am like that.

Pumping causes cavitation though, meaning more bubbles. 1 pump ONLY before bleeding!

Tim, if you are talking about the clutch slave, you need to remove it, turn it over and bleed with the bleeder valve pointing up. Press the plunger in while opening the valve. I can do it with my hands, but I have huge burly hands, most guys can do it though, it is just painful.

You may want to go as far as to "bench bleed", which is a major PITA IMO.

GL!
Luke

[goinstrong]

Luke,

I just came in to write and ask if I needed to have someone press the clutch in while I used the power bleeder. Your response answered the question.

We have a slave cylinder to replace on one of my E21s today, so you just addressed how we make sure that one is ready to go. Thanks!

Tim

[goinstrong]

So...once the air was out of the line, the clutch worked perfectly. Thanks everyone!
I ended up using the pressure bleeder from the reservoir, pumped to 14 psi, opened the bleeder valve, and pumped the clutch a bunch of times until the air went away and only fluid filled the bottle. Works perfectly now.

Tim

[DaveSmed]

Tim, if you are talking about the clutch slave, you need to remove it, turn it over and bleed with the bleeder valve pointing up. Press the plunger in while opening the valve. I can do it with my hands, but I have huge burly hands, most guys can do it though, it is just painful.

I have to disagree with that. If you have an old one laying around, take it apart. While the bleeder is mounted on the bottom of the slave, there is an internal passage so it draws from the top of the bore. It is designed to be bled as installed.

Them Germans huh? Think of everything. (except quality dashboard materials for some reason...)

[Adrian_Visser]

$15 and half an hour:







I need to stop by a tire shop and pick up an all-metal valve stem to mount in the bottle to allow bleed off. Makes for a damn quick fluid change...but I need to pick up a few feet of 1/4" clear tubing so I can put it on the floor instead of on the motor.

GL!

Luke

http://www.stoptech.com/tech_info/wp_brakefluid_1a.shtml

Luke have you ever read this article off of StopTech's website? It mentions that using a pressure bleeder without a built in diaphram to separate the compressed air from the brake fluid forces air into the brake fluid in the form of tiny bubbles. According to the article it is more of a problem with the higher boiling temp fluids, just some food for thought.

[StereoInstaller1]

http://www.stoptech.com/tech_info/wp...fluid_1a.shtml

Luke have you ever read this article off of StopTech's website? It mentions that using a pressure bleeder without a built in diaphram to separate the compressed air from the brake fluid forces air into the brake fluid in the form of tiny bubbles. According to the article it is more of a problem with the higher boiling temp fluids, just some food for thought.

Hmmm. I read that article carefully...basically, yeah. Time to not use by little pressure blaster. I knew about they hydorscopic properties of brake fluid...and never though a second about the idea of shoving air into my brand new fluid.

Duh.

And Dave, they built that valve upside down on purpose? WTF? I should have figured something like that when the voices in my head were saying "BMW would not do that" but I didn't wanna listen...