Hi, chevy express van with 14,050 gvwr dually chassis. 4 wheel abs disc brakes.
I overheated them coming down a mountain ( not enough to smoke em, but I could smell them for the last few minutes at the bottom of the grade)and am getting a slight pulsing in the brake. Not during slow speeds but slowing down from highway speeds or under a harder push on the brake. I don't remember if it did it before they overheated or not. I am not sure if it's the abs or a mildly warped rotor.

Can I tell if it's warped with a dial indicator while the rotor is on the truck? I have a mag mount for the indicator or can rig a solid mount - dial reads .001 -- or is there another way to check.

Does anyone know how much runout is allowed in specs for the rotor?

Thanks

 

The vibration probably is your rotors. They tend to vibrate more braking from highway speeds. As is the case with large vans, most of the time you will not feel the vibration at low speed.

The minimum thickness should be stamped on rotor somewhere. Most likely on the inside of the bell unless its a drum-in-hat rotor.

 

I don't know what it is about stock rotors and heat. My guess is they try to make 'em light and slim but don't drill or slot (for obvious cost reasons). The old (and I mean really old ones) were thick, heavy and bullet proof as a result. If it is the stock rotors and you plan to keep the van, I'd sure look into new rotors from Stainless Steel Brakes. Spendy yes, but worth every nickel when you're trying to bring 14,000 to a standstill. Just my opinion though.

 

Welcome to the forum
you may be able to free spin the rotor with the wheel off and see the warp, but if you got them hot and you know it, theres a good chance they are warped.