front rotor replacement

[pa12.5]

could anyone tell me if the front rotor needs to be reriveted to the hub? I want to replace both rotors and install the new stainless calipers but I don't know if they have to be rerivited. Thanks for your help.

 

[JohnZ]

They don't HAVE to be riveted, as the wheel will hold them on just fine; they were riveted originally so the rotor surfaces could be machined as a unit with the hub, turning on its bearings to minimize lateral runout of the rotor. If the lateral runout exceeds .005" TIR (Total Indicated Runout), the rotors will "pump" the caliper pistons (due to the constant-contact design) and will introduce air into the calipers.

If you replace the rotors, attach them tight with backwards lug nuts, set up a dial indicator on the spindle, and check the runout; if it exceeds .005" TIR, keep re-indexing the rotor on the lug studs and see if you find a position where the runout is within specs. If you don't find one, put the rotor on in the least-runout position and take the car to a dealer or quality brake shop that can resurface rotors on the car and have it done.

If your original rotors (if they're original) aren't scored or obviously worn to the point where they'll be below minimum thickness if resurfaced, just leave them alone. Stock GM rotors will last virtually forever with stock GM pads; Metallic "race" pads will definitely "eat" the rotors, and are a complete waste of money on a street-driven car.

 

[80convertible]

I did not reinstall rivets when I replaced my rotors. Have fun drilling out the rivets. Kind of a pain in the azz. Have a sharp drill bit and start with a smaller bit then a larger one. Have a good punch that you can pop them out with. Also, lots of WD-40. My cordless drill kept running out of battery power.

Jim

 

[wicky88s1975]

I just did mine. ditto to the Have Fun part.

 

[pa12.5]

Boy are you right. I spent half a day trying to get one off. I went thru most of a can of WD40 and decided to just let it soak in over night. The next morning the rotor came right off. So I did the same with the rest of the wheels. Thanks for the help. This is a great place for good info.