96 k1500 brake problem

[tempfixit]

1996 k1500 5.7 engine 114,000 miles

Sometime ago the brake line by the fuel tank leaked, replaced line and bleed brake system. Since then the brake pedal pulsates at low speeds. I took off the brake caliper on the RF to remove plate to get at wheel sensor to check and clean, in process I broke my socket so I had to put back together. I had pushed the caliper piston back into caliper too get brakes caliper back on. I drove vehicle for couple months without the brake pedal pulsating at all, recently it began pulsating again intermittently. Would it be air still in the brake system or should I get to wheel sensors and check them?? I believe the bleeding procedure is RR< LR< RF> LF. Any suggestions greatly appreciated.

[horse482]

First can you hear the the abs motor when the pedal pulsates? If so then abs problem, if not then other problem. Have you checked to see if your brake rotors are true? You may want to take them to a parts store and have them turn them.

[silverado122775]

If you did not bleed the lines properly, you would get the mushy pedal. but it sounds like you may damaged the abs sensor.

[tempfixit]

Thanks for input horse482 and silverado122775.
I do hear what I think is the abs motor when this occurs, and it feels like a rotor is warped before it pulsates. Silverado are you refering to the abs wheel sensors? I do not have a Haynes repair manual and autozone.com does not have it online either, so if someone know the correct brake bleeding procedure I would greatly appreciate the information so I can try bleeding system properly. Thanks again for all the great info.

LS

[horse482]

When bleeding a brake system you need to start farthest away from the master cylinder first. Unless you have the proper equipment you need to have someone help you. You or your buddy pump the pedal half a dozen times or until it starts to get hard (engine not running), while the other person cracks the bleeder screw. Start at the left rear. Do this until there is no more air bubbles in the brake fluid. Check the m/c often to make sure that you don't run it dry. Next the same process on the left rear, then right front, then left front. Hope this helps.

[tempfixit]

Thanks horse482. I will bleed them this weekend and drive too see what the results are and post.

[abaird]

Did you have the bleeder screw open when you pushed in the caliper piston? If not, sending all that fluid back through the ABS unit can be harmful and you will need a scan tool with ABS capability to properly bleed the system. From what you describe it sounds more like an ABS problem than just air in the lines. Air in the lines will result in a spongy or low pedal.

[tempfixit]

Originally Posted by abaird

Did you have the bleeder screw open when you pushed in the caliper piston? If not, sending all that fluid back through the ABS unit can be harmful and you will need a scan tool with ABS capability to properly bleed the system. From what you describe it sounds more like an ABS problem than just air in the lines. Air in the lines will result in a spongy or low pedal.

I removed wheel speed sensors from front hubs and cleaned rust from hub surface and sensors surface. Reinstalled, the pulsating has not occurred. Problem solved.