JTA

Just got a 98 c2500 Silverado and it needed a brake job. I replaced everything (rotors, drums, calipers, wheel cylinders, etc.) front and back , I even got a second set of rotors thinking the first ones were bad. I'm still having the pulsating issue. Along with the pulsating the pedal is also soft as well. I've bled the system 10-15 times. Not sure were to go from here maybe an issue with ABS?

Jeepwalker

Your rotors are still warped. I'd say about 1/3 of the rotors I buy don't measure out very well once I install them, you need to use a dial indicator to make sure they are dead-nuts on or it's just guesswork. Remove them, make sure to very carefully clean the mating surface of the truck's hub with a file and razor blade to there is NO rust or any debris of any sort. Install the rotors and get some large nuts (larger than the studs) and lightly bolt the rotors to the hub w/o the wheel. Get and put a dial indicator on them (I use a Harbor Freight magnetic base on a heavy piece of steel on a 5 gal bucket) and rotate the rotor. Mark the rotor to the hub with a piece of tape or a paint pen. If it's more than .004, then rotate the rotor on the hub clockwise one stud and remeasure. Keep doing until you find a spot where the dial indicator needle doesn't move, or hardly at all. Might even need to swap the rotors left to right and do again. You can always shim the backside with a piece of thick paper ...but at that point I would return for a replacement rotor. You should be able to get it right on with NO needle movement at all.

Make sure your caliper isn't hanging up too, otherwise if it drags, it'll warp the new rotors. Good luck!!

J

jrow8162

Are you losing any brake fluid? Not sure if that year and model has vacuum assisted braking but brake fluid leaking from your master cylinder into your booster would cause that. A bad booster would cause that as well. Do the brakes heat up? Rotors glowing?

tech2

if the vibration is transferred into the pedal and not the steering wheel; its probably out of round drums.
through the steering=front, pedal=rear
have to agree with jeepwalker. unless you buy the expensive oem parts ($400 each where i am) the new drums are out of round. even the ac delco cheaper line had issues. Its so common the i put new drums on the brake lathe right out of the box and most are 0.010 out of round.

soft pedal that firms up when pumped is air in the system