1989 Z28.

GM 10 bolt with conversion plate from Flynbye and I am using reproduction 4th Gen 10 bolt caliper brackets from Rock Auto.

Issue: The pads need to sit lower.

Is there a difference (depth) between 3rd Gen 10 bolt caliper brackets vs 4th Gen?

Or is the issue the conversion plate?

I'm looking for original GM 10 bolt caliper brackets to see if this improves.

Thank you

 

If you had stock parts you could measure and check.
Either call both places and see whats up or you can over size the holes, put a grade 8 washer on there, put caliper where it needs to be then snug it down. Then weld washer in to place.

 

What pads are you using?

 

Same brackets for 3rdgen and 4thgen (93-97).
Same pads for each.
"Same" caliper, size and fit.
3rdgen rotor is 11.6" ish diameter; 4thgen rotor is 11.5" ish diameter.

If you got 3rdgen rotors, then the backing plate is likely the issue. Backing plate is for 3rdgen conversion? But if you got 4thgen rotors to go with your "4thgen" brackets, then the smaller rotor is likely your issue?

Plenty of people have used Ed's backing plates, and I've not read of anyone having your issue, or at least noticing/mentioning it, so the plates are probably correct.

Given all that, then perhaps the 4thgen backing plate might place the bracket and caliper about .1" lower than the 3rgen backing plate, although I kind of doubt the backing plates vary; GM probably just left the 4thgen pads sitting about .1" too high, like you've got there.

 

Pads for 3rd gen PBRs (89-92) and 4th gen PBRs (the ones you seem to have, 98-02, butt I'm not sure) are a different part #. I have no clue what the details in the differences, if any, are.

Having no experience with all possible permutations, it seems possible to stuuuuuupid me, although maybe not to smaaaaaarrrrrrttttttttt you, that using the one kind of pads in the other kind of brackets, can lead to unintended consequences.

What pads are you using?

 

Rear calipers and brake pads are '89.

The caliper brackets are 4th Gen 93-97 and the backing plate is for a 12" rotor, not 11.6" Problem solved.

Thank you for your response

 

​​​​​​​And the solution was ... ???

 

Bigger rotors.

I forgot the backing plates were for 12" rotors. That's what I get for boxing things up and opening many years later.

 

Gotcha. Makes sense.

Match the parts to the parts, not to the sheet metal you wrapped em in.