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View Full Version : Strange brake system issue, looking for opinions

Deadly_Evolution
11-30-2011, 06:40 PM
So I was diagnosing and replacing what appeared to be a stuck brake caliper on a 96 GMC Jimmy, replaced the caliper and pads, went to bleed the brakes and the brake fluid shot out of the brake master cylinder reservoir like a geyser several feet in the air from both the front and rear portions of the reservoir.

My guess is a blown seal on the piston shaft on the master cylinder but just wanted to see what others thought.
TomKat
11-30-2011, 08:27 PM
Unlike Japanese cars GM master cylinders will spit fluid in the air when the brakes are applied. Shouldn't send it into the air several feet though.

Did you try putting the cap on and bleeding the brakes?
Deadly_Evolution
12-01-2011, 12:22 AM
Unlike Japanese cars GM master cylinders will spit fluid in the air when the brakes are applied. Shouldn't send it into the air several feet though.

Did you try putting the cap on and bleeding the brakes?

No and the service manual states to remove the cover when bleeding.
DoWork
12-01-2011, 12:39 AM
I recently did rear lines on a Sierra that did the same thing. We put the cap on and it bled fine after that(well, after we got the ABS pump "bled").
TomKat
12-01-2011, 06:12 AM
No and the service manual states to remove the cover when bleeding.

Hmm. They may be referring to gravity bleeding.