Front brake pads on my 2000 Blazer were thin so I swapped them out for new ceramics. After install, pedal was low even though I did not open the system in any way, just compressed the pistons. I bled the system, great pedal until I start the truck then it sinks nearly to the floor. Drove it a short distance. There is a burned brake smell.

The rear pads were a bit thin so I replaced them. Bled the system again, same results. Tall pedal until the truck is started then nearly to the floor.

So far I have replaced the front pads and rotors, rear pads, rotors and calipers.

I am confident the air is out of the system but I am not sure about the ABS. Could the problem be the proportionong valve?

Thanks and Regards

Phil

 

does it drop to the floor instantly? or does it go like 75% and then smush the rest of the way slowly?

 

I would try changing the brake fluid. It is possible you pushed junk from the calipers (lowest point in the system) up through the ABS unit and the master cylinder, possibly causing a leak past a seal or just hanging something open that is not supposed to be.

 

Thanks for both replies. And Koop yes I believe that describes the problem. And where is the proportioning valve? Is it part of the ABS?

Regards,

Phil

 

Which part? Does it go all the way to the floor without hesitation?

or

Does it go 75% of the way then slowly to the floor for the other 25%?

 

how does the fluid look? if its almost black then i would change it. i have found the best way to bleed the air out of the abs block (without a scan tool) is to drive on grass or loose stone and then slam on the brakes to activate the abs, do this about 10 times then bleed the brakes and ALL the air should be out.

 

Oops! 75% fast then slowly the rest of the way. That's with the motor running.


Also the fluid was not very dirty when I started but the braking on grass sounds worth a try.

Regards

 

Brakes are working now. I engaged the ABS several times on grass, immediate difference in the pedal. Not perfect but driveable. Just needs a bleed tomorrow and will be ready for the road. Thanks all and Best Regards.