To begin with, adjust the rear brake shoes so that there is no drag at all. I always leave extra clearance for drum brakes because when you do several backups the self-adjuster will set it to the proper clearance. If it's too tight, will it contribute to your problem; maybe yes - maybe no.The install was pretty straightforward. Neither the pads nor the shoes were worn to the metal, not even close, so I'm not sure where the grinding sound was coming from. Basically it didn't need a brake job, but the money was already spent, so I pressed on. Once complete, the pedal was a bit low and not as firm as I expected, so I bled the system again and adjusted the rear brakes to get a slight drag on the drums. That took care of the pedal, but now I get this weird hopping in the rear when I apply the brakes. It isn't too bad when the brakes are cold, but it gets worse as they get hot. The back of the truck jumps pretty hard when I hit the brakes for a quick stop. It almost feels like wheel hop that some cars experience under hard acceleration, but when I'm stopping. I've never seen anything like that.
Now I'm wondering if I got the adjustment too tight or the ABS is acting up or maybe some combination of the two, but I'm not sure. Any ideas? Thanks.
Make sure the parking brake is properly adjusted; 6 - 8 notches on the pedal stroke should do it. There should be no drag when parking brake pedal is fully released.
Bleeding Brake System
● If master cylinder is suspected to have air inside, bleed air from master cylinder first.
● Turn ignition switch OFF and disconnect the ABS/VDC connector or battery cable.
● Bleed air in the following order.
– Left rear brake
– Right rear brake
– Left front brake
– Right front brake
– ABS actuator/VDS
If you're still having your "jumps", it could be a problem in the ABS system. Temporarily disable the ABS system by disconnecting the ABS connector. Drive the vehicle to see if it clears up the problem.