very soft brake pedal

1998 GMC C1500
150,000 MILES • V8 • 4WD • AUTOMATIC
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GMC1998
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  • 1 POST
1998 GMC k1500 v8 5.7 extended cab brakes. With engine off pressing of brakes feel hard, when you start the truck they go to the floor. Master cylinder, both rear cylinders/drum pads have been replaced. all wheels have been bled. what does the pressure distribution box do for brake lines. It has multiple lines going in. Brake pedal feel real mushy and is very close to the floor. Brakes do stop truck. I heard there was a balancing pressure device in some other trucks could this be causing my issues?
Mar 16, 2009 at 6:53 PM
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JERRYGOODWRENCH
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This is a common issue. The problem is you have air stuck in the ABS unit and a scanner must be used to open the valves in the ABS unit wile bleeding the brakes. This guide should help

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

Please let us know if you need anything else to get the problem fixed.
Apr 19, 2009 at 6:23 AM