C2: Bent Caliper Bracket?

[Dan Pepper]

I noticed the front right caliper on my '66 leaking, so I this weekend I installed a new set of VB O-ring calipers. After bolting them on and bleeding I noticed that the right caliper appears to sit on the braket so the top of the caliper is cocked slightly inboard making it so the faces of the pistons aren't parallel to the pad backing. In other words, when looking at the inboard half of the caliper, there is approx. 1/8" difference between how far the top piston extends to touch the pad as compared to the bottom piston (and reverse for the outboard caliper half). It's most noticable by looking at how the pad backing lines-up (or doesn't in this case) with the flat inside edge of the caliper housing.

I thought that the piston faces, pads and rotors should all be parallel to each other- so my first thought was that the bracket may be bent, thereby causing uneven presure on the pistons that eventually caused the old caliper to blow.

Looking for an immediate answer, I called a mechanic at Rick Stark Enterprises here in the Seattle area, the local Corvette/racing specialist, and he said that's normal for corvettes - that it ensures that the pads clean the leading edge (of at least one side?) of the rotor as it turns. Kinda sounds funky since the driver's side caliper/piston/pad/rotor components appear perfectly parallel to me.

What is correct?

[Joe Lucia (12484)]

Re: C2: Bent Caliper Bracket?

Dan------

The fellow that you spoke with is correct about the fact that the condition is "normal" for Corvettes, but he's incorrect about the implication that it's designed that way for the purpose he described. What's "normal" is distorted front brackets. Sometimes, they were this way from the factory. The front caliper mounting for 65-82 Corvettes had "shortcomings", to say the least. For J-56 cars, extra supports were added. I think that all 65-82 Corvettes should have had these brackets and I've added them to my car. However, even with the extra brackets, one has to be very careful about installation or one will end up with even more distortion of the main caliper bracket. None of these parts were really very "precision manufactured".

[Dan Pepper]

As always, Thanks Joe. *NM*

[Joe Lucia (12484)]

Addendum

I should also have added, that correct alignment of the front disc brake pads is a function of 2 things: the first is the exactly correct, as designed, configuration of the caliper bracket. The second is the exactly correct, as designed, configuration of the calipers, themselves. Due to bracket distortion and "manufacturing tolerances" of the brackets and final caliper machining, correct alignment is rarely achieved. That's why most 65-82 Corvettes will wear brake pads unevenly.

This can be field-corrected to some degree by re-machining and/or shimming of the caliper-to-bracket machined surface. This is very tedious and time consuming and the results probably don't justify the effort.