SERIOUS brake problem
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97 Expy SERIOUS brake problem
I have a 97 Expy 4X4. Today I pulled out of a parking lot, and pulled up to a light. I applied the brakes, lifted, and immediately applied the brakes again. On the second application the pedal went twice as far as the first. I started experimenting, and found that the more I pump the brakes (has to be done quickly), the further the pedal will depress, until it hits the floor. Once left for a few seconds, the process starts over. I stopped at the part store on the way home, and bought some pads because I had been planning on changing them anyways, and thought I may get lucky. I changed front and back, and unfortunately the problem still exists. The system isn't losing any fluid, and there wasn't any work done to the truck preceding the incident. I'm thinking the booster is leaking air. Just wanted to see if anyone has experience this problem. Also, is the booster a dealer part, or can I pick one up at a part store. Thanks.
Brandon
Brandon
Last edited by OKLAHOMAF100; Jul 3, 2005 at 01:12 AM.
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From: Tucson
The brake booster only assists in pushing the master cylinder piston. If the booster leaks or fails the brakes will be hard as a rock and the truck will be had to stop. You might also get a CEL for the vaccume leak. Sounds like the piston in the master cylinder is shot. I would start there as a most liekly. The only other thing I can think of that would cause a pressure loss is the ABS controller. It's job is to reduce line pressure to a locked up wheel. Do you have the normal ABS light when starting the truck and then it goes out?
Dave
Dave
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All the lights are normal. ABS comes on when the truck starts, and then goes out. There aren't any warning lights. I guess I'll pick up a master cylinder, and go from there. Thanks for the advice.
Brandon
Brandon
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Well, I changed the master cylinder, and flushed the fluid at all four corners. This thing stops on a dime with that along with the new pads. I haven't had a hint of the problem either. Thanks for the tips. I have had master cylinder problems in the past (on another vehicle), but it was opposite of this. The first push, it would go to the floor, and you would have to pump them to build up pressure. I have to say this was a new one for me. That's why I was looking at something else being the problem. Thanks again for the help. Saved me some time and money.
Brandon
Brandon
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