1993 GMC Suburban soft pedal

1993 GMC SUBURBAN
130,000 MILES • V8 • 4WD • AUTOMATIC
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TONY1956
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Had all brakes relaced and several brake lines, and master cyl.(2 Yrs ago) Pedal will over time get"soft" go to floor and cause brake warning light to come on. Each time( every 3- 4 mo) have brakes bled and am told no leaks in system. Brake will be fine and gradually return to "soft". System has a unusual brake device that is connected to the 2 bowl master cylinder, then a seperate line originates there for each wheel cylinder. It is an aluminum casting with fins and has at least 2 bleeder valves. The mechanic will not touch it. I think there is air trapped in it even after bleeding the lines. Please provide me a suggestion or 2. Thanks Tony
Sep 28, 2009 at 4:57 AM
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DOCFIXIT
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Hi
The thing is part of anti-lock brakes no bleeding necessary unless replaced. Are rear brakes disc or drum?
Let me know
Thanks for donate
Sep 28, 2009 at 9:27 AM
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TONY1956
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Thanks for answer/question: Front Disc and rear drum. Never had a problem w/brakes untill I had Master cylinder and all other work done. Never have seen a leak anywhere of any significance; that is to say no wet spots anywhere. Tony
Sep 28, 2009 at 11:59 AM
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DOCFIXIT
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Assume no fluid loss? need to check rear wheel cylinders. Pull dust cups back and see if wet with fluid. If so that is how air is getting in. if all good there pull master away from booster no need to remove lines check for leak at master.
Sep 28, 2009 at 12:05 PM