Brake Bleeding Fail: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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Oct. 9, 2011 11:24 p.m. procainestart Dork

I swapped a full set of calipers and a clutch master today, then pressure-bled everything. Brakes ended up soft, so I re-bled, to no avail. So I assume I somehow got air in the brake master? I did drag some of the reservoir's fluid out with a turkey baster but I didn't suck it dry.

So do I have to take the master off and bench bleed it? What's my next step?

Meanwhile, I have to vent: over the past few months, almost ALL of the wrenching I've done has ended up a clusterberkeley. Misdiagnoses and failures to repair E36 M3, sometimes twice, buttoning up an engine, only to have abort re-install because I berkeleyed up the flywheel bolt torque spec, and basically sucking. My point: if you've been feeling really skilled lately and don't always, maybe it's because I've been acquiring tons of E36 M3ty car repair karma.
Oct. 9, 2011 11:57 p.m. BoxheadTim SuperDork

procainestart wrote:

Meanwhile, I have to vent: over the past few months, almost ALL of the wrenching I've done has ended up a clusterberkeley. Misdiagnoses and failures to repair E36 M3, sometimes twice, buttoning up an engine, only to have abort re-install because I berkeleyed up the flywheel bolt torque spec, and basically sucking. My point: if you've been feeling really skilled lately and don't always, maybe it's because I've been acquiring tons of E36 M3ty car repair karma.

In case that makes you feel better, my infamous "inverse Midas touch" seems to have been working overtime for me re vehicle repair, too...
Oct. 9, 2011 11:57 p.m. donalson SuperDork

for the brake master... if you've got room i've read of people bench bleeding it in the car, pull the lines, get some hose and fittings to fit where the lines go... loop hose from the fittings to the reservoir, pump pump pump pump....
Oct. 10, 2011 7:54 a.m. porksboy SuperDork

Got ABS? If so often air will get trapped in the ABS unit. It may need to be cycled while being bled to get the air out.
Oct. 10, 2011 9:45 a.m. procainestart Dork

In reply to porksboy:

No ABS on this car.
Oct. 10, 2011 11:19 a.m. mad_machine SuperDork

what is it.. that might help us
Oct. 10, 2011 1:57 p.m. porksboy SuperDork

Look for a line, maybe a loop, that is higer than the M/C or the surrounding line. Anywhere air could get stuck. On my Fiero GT I got air in the clutch line when bleeding it once. Only way I could get it out was jack up the left side of the car. That put the bleeder at a high enough point to get all the air out.
Oct. 10, 2011 5:17 p.m. procainestart Dork

mad_machine wrote:

what is it.. that might help us

89 Saab 900 Turbo
Oct. 10, 2011 7:30 p.m. ansonivan Dork
- make sure the brake rod adjustment (if applicable) is sufficiently loose to allow the new master cylinder to fully retract.
- with no bleeders open try short little dabs at the brake pedal at the top of the stroke, like half an inch of pedal travel. Do this a lot.
Oct. 10, 2011 11:41 p.m. mad_machine SuperDork

did they have ABS in 89? I know my 87 doesn't have it.. but my 91 did
Oct. 11, 2011 6:22 a.m. porksboy SuperDork

Just reread your original post. You say you replaced the CLUTCH master and two BRAKE calipers. You may have berkleyed the BRAKE master when bleeding the calipers. There is often crap in the bottom of the bore of the master, when you bleed the brakes you get into the crap, they get damaged along the sealing surface and the cups start to leak. No amount of bleeding will get the master to build pressure. Rebuild or replace. T avoid that in future, flush the system regularly and place a block under the pedal to keep the master from depressing all the way and getting into the unused portion of the bore.
Oct. 11, 2011 9:41 a.m. procainestart Dork

In reply to porksboy:

I replaced all four calipers, then pushed a quart of brake fluid through the brake system, and then r&r'd the clutch master so that it would draw only clean fluid from the (connected) brake reservoir. I did not use the brake pedal to bleed; I used one of those relatively inexpensive bleeder systems that you fill with fluid, screw onto the reservoir, and pressurize. Can what you describe happen if the brake pedal isn't used to bleed?

@ mad_machine: ABS (& airbag) = '90+
Oct. 11, 2011 9:59 a.m. nderwater SuperDork

You installed the calipers with the nipples facing up, right? One time I was in a hurry to get done and accidentally switched the right and left calipers, installing them upside down - bleeding doesn't work well from the bottom!
Oct. 11, 2011 10:12 a.m. procainestart Dork

In reply to nderwater:

Fortunately for people like me, the calipers will only go on one way, so, yeah, nips up.

@ ansonivan -- I used the "pedal swatting" technique on the clutch years ago but had forgotten about it -- I'll give it a shot; thanks.
Oct. 11, 2011 10:12 a.m. procainestart Dork

In reply to nderwater:

Fortunately for people like me, the calipers will only go on one way, so, yeah, nips up.

@ ansonivan -- I used the "pedal swatting" technique on the clutch years ago but had forgotten about it -- I'll give it a shot; thanks.