Rotors available (for now) for K-H disc brake cars
A follow-up on this thread. So...I purchased expensive ( $75 and $120 each) rotors from two additional vendors that both claimed to have the proper rotors for early A bodies and yes, they are "guaranteed to fit". Neither set fit, they rubbed the seals, and were returned.
Summit carries the Centric 121.63005 for $29.95 each, I ordered a pair:
Centric Parts 121.63005 Centric C-Tek Standard Brake Rotors | Summit Racing
This rotor appears to be the same as the others, including the above mentioned expensive rotors, and Rock Auto rotors. The dimensions are all pretty close as best I can tell. The restoration shop I'm using for body and paint has a machinist lathe they let me use, so I cut down the hat on both rotors about .075". I had to go that far to eliminate rubbing on the caliper seals. It is hard to measure the hat wall thickness, but I do have an outside caliper I was able to fish through a bolt hole, measure, remove and measure the gap. The cone (hat) wall was somewhere between .260" to .280" prior to cutting, depending on where it is measured. it's about .185" to .205" now, so I had to take off about a third of the wall thickness. Again, these dimensions are approximate because they are very difficult to measure. By the way, these are good rotors, I have a dial indicator and checked run out of the rotor face after installation; it was +/-.001". That's hard to beat.
I do have concerns about removing a third of the hat wall thickness, but since the hat only carries force when braking, is not a friction surface, does not support the wheel only the rotor, has safety been compromised? The failure mode I could envision would be under heavy braking, but I would think the wheel would lock up before the hat cracks. I am not a metallurgist or a machinist, although I did have take some classes in both areas in tech school. Is there a safety concern here? Comments welcome.
A follow-up on this thread. So...I purchased expensive ( $75 and $120 each) rotors from two additional vendors that both claimed to have the proper rotors for early A bodies and yes, they are "guaranteed to fit". Neither set fit, they rubbed the seals, and were returned.
Summit carries the Centric 121.63005 for $29.95 each, I ordered a pair:
Centric Parts 121.63005 Centric C-Tek Standard Brake Rotors | Summit Racing
This rotor appears to be the same as the others, including the above mentioned expensive rotors, and Rock Auto rotors. The dimensions are all pretty close as best I can tell. The restoration shop I'm using for body and paint has a machinist lathe they let me use, so I cut down the hat on both rotors about .075". I had to go that far to eliminate rubbing on the caliper seals. It is hard to measure the hat wall thickness, but I do have an outside caliper I was able to fish through a bolt hole, measure, remove and measure the gap. The cone (hat) wall was somewhere between .260" to .280" prior to cutting, depending on where it is measured. it's about .185" to .205" now, so I had to take off about a third of the wall thickness. Again, these dimensions are approximate because they are very difficult to measure. By the way, these are good rotors, I have a dial indicator and checked run out of the rotor face after installation; it was +/-.001". That's hard to beat.
I do have concerns about removing a third of the hat wall thickness, but since the hat only carries force when braking, is not a friction surface, does not support the wheel only the rotor, has safety been compromised? The failure mode I could envision would be under heavy braking, but I would think the wheel would lock up before the hat cracks. I am not a metallurgist or a machinist, although I did have take some classes in both areas in tech school. Is there a safety concern here? Comments welcome.