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Wrong calipers?

923 Views 15 Replies 9 Participants Last post by  brading
Talking about a 77 Corvette.

The caliper is mounted too close to the rotor to the point of rubbing the back side of it. I can't quiet figure out what's off. Do I need a thinner rotor or is the wrong type of caliper being used? Check our this image:
Automotive design Tints and shades Personal protective equipment Automotive lighting Auto part


From the other side
Automotive tire Hood Automotive lighting Grey Motor vehicle


Here is what the caliper bracket looks like:
Automotive design Automotive tire Auto part Automotive fuel system Personal protective equipment


Look at the grooves on the back of the rotor the rubbing has caused:
Tints and shades Automotive exterior Gas Bumper Auto part


The pads seem fine, which I don't think should make a difference anyway.
Automotive tire Vehicle Automotive design Rim Bumper


Everything appears to be nice and tight, it's as if the part of the caliper that goes between the bracket and the rotor is too thick. What am I missing here?
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Talking about a 77 Corvette.

The caliper is mounted too close to the rotor to the point of rubbing the back side of it. I can't quiet figure out what's off. Do I need a thinner rotor or is the wrong type of caliper being used? Check our this image:
View attachment 627572

From the other side
View attachment 627574

Here is what the caliper bracket looks like:
View attachment 627576

Look at the grooves on the back of the rotor the rubbing has caused:
View attachment 627577

The pads seem fine, which I don't think should make a difference anyway.
View attachment 627579

Everything appears to be nice and tight, it's as if the part of the caliper that goes between the bracket and the rotor is too thick. What am I missing here?
The pistons have to come out enough to give clearance for the rotor. In one of the pic's one set of pistons are out the opposite side appear to be bottomed.??
 

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Not knowing the history of this 45 year old car, the pix look like the rotor diameter is either too large for the caliper or if the rotor is correct, the caliper is wrong. I'm gonna guess a 12" rotor under a caliper designed for 11.75" rotors...

Russ
 

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Discussion Starter · #9 ·
According to this Russ is right.

This is interesting. However, looking at the grooves on the rotor from rubbing on the caliper, I would think the issue is with the thickness more so than the diameter of the rotor. What's the difference between nominal thickness and minimal thickness?
 

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Yeah looks like there are 2 pistons on each side. Makes me wonder why have pistons on the outer side where they aren't controlled by the master cylinder.
Internal passages in the caliper allow fluid to feed both sides simultaneously .
As to the rotor surface , how long have those rotors been in use ? That looks like wear when the pads wear out .
As to proper diameter , get out your measuring tools .
 

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Caliper doesn't appear centered or the wrong parts altogether. I'd buy all new ones from Rock Auto and compare old and new. Rock Auto also has pretty good pictures on most things.
Four piston calipers are rigidly fixed and the pistons on either side make up the pad wear compensation. Unlike a 2 piston caliper that floats back and forth as needed.

 

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If this is on the rear you have front rotors on the back. There is a difference in thickness of the rotors, and the offset
It could also be rear rotors on the front. That rotor looks wrong offset and too thin, based on how much piston is showing on the outside with what appear to be brand new pads. With new pads, both sides will have the pistons just about fully retracted.
 
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