Hello

I own a 98 GMC Sierra Z71.
I have recently been having problems with my brake system. I have had everything looked over and or changed. My break pedal is spongy and I am able to push it all the way to the floor. My breaks do work, when the pedal is compressed all 4 tires will stop, but there is not much to the pedal. I have myself bled the line a number of times and have also had a professional bleed them and look over the system.
I have been told that possibly the Dump Valve in the ABS unit is stuck or not working. I do not want to buy a new ABS unit and I am wondering if anyone knows if the ABS unit can be bypassed entirely and how?

Thanks.

 

I've got a '97 Silverado and the ABS light has been on since I bought it about a year ago. I looked into it and a lot of what I read indicated there were problems with the ABS sensors (located in the wheels) on these years getting dirty, especially in areas where they use salt on the roads in the winter. The dirt, or salt messed up the sensor somehow and made the ABS engage anytime you depressed the brakes, and made them feel spongy and also took forever to stop.

It turns out on my truck, that the previous owner had pulled the ABS relay from under the hood. Doing this does not affect your regular braking in any way, just disables the ABS system.

I just put new pads, shoes, rotors and drums on mine b/c the brakes were getting super spongy and it made a world of difference.

Hope this helps.

Matt

 

Pulling the fuse(s) will disable the EBCM and motor killing ABS, but this sounds more like an actual hydraulic issue. It could be an internal issue in the BPMV. I wouldn't be surprised if it were just the master cylinder though. Are you continuously able to bleed air out of the system? If so, I wouldn't think BPMV is at fault.