Mechanics

CANT BLEED BRAKES

2003 Chevrolet Tracker • 92,000 miles

No abs on unit. Replaced two rotten rear brake lines. Replaced master. Replaced both front calipers.I am a licenced mech for over 20 years and this unit will not bleed.3 lines off front section of master and 1 on the rear.2 lines of the front section go to each wheel (no proportioning valve) one line goes to valve over the rear axle. The one line on the rear of the master also goes too the valve over the rear axle. Out of the valve comes one line to the rr wheel cyl then a line out of the rr goes across to the left. Cant gravity bleed even tried the vaccuum method and no luck. Any sugestions
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Colin2001
April 10, 2012.



I'm not familiar with that specific system but it sounds like what happens on GM front-wheel-drive cars when you press the brake pedal too far during pedal-bleeding. A valve in the master cylinder trips and blocks the two ports that weren't building up as much pressure, as in when there's a leak. The only way I ever found to reset that valve was to give a quick short burst of compressed air into one of the open bleeder screws at a wheel that won't bleed, then let it gravity-bleed. If you have to irritate the brake pedal a little by hand to get the flow started, just press it an inch or two a few times.

Caradiodoc
Apr 10, 2012.