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Need Brake Expertise to Identify Rotors

Road Grabber

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I have a charger and road runner with disc brakes.
I have had extra rotors for years removed from cars over the years and have other rotors I can’t seem to place.

The Road Runner and Charger brakes have rotors that measure 11” OD with backside openings that measure 7” diameter.

I thought I could use these other rotors but when I measure them they have 11-3/4” outer diameter and backside openings 7-3/4 diameter.

The service manual says I should have these measurements in the car yet the ones I have are smaller. I have the Kelsey-Hayes single piston calipers. My installed rotors are closer to an inch. That is what I see in a 70 Dart service manual yet I know the cars did not have disc brakes I installed from an A Body.

The other extra rotors are 1-1/4 thick. The bearing races are the same. They would probably fit but the pads shouldn’t rub correctly.

Did Chrysler ever put these smaller rotors on b bodies? Are they C body rotors? I did strip a 68 Chrysler 300 years ago. Maybe it’s from that car?

I’m open to possibilities here.

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The 12” rotors look and measure like C body and the original disc size on a 68-70 b body would have been 11”
 
The 12” rotors look and measure like C body and the original disc size on a 68-70 b body would have been 11”
Thanks for the reply.

It's just odd that the service manual for my charger says those larger measurements are what should be on the car.

My rotors can't be for an A body because the bolt pattern for a B Body.

The A body Dart manual matches with what's on the cars now. Books have been wrong before....

Any idea what year C Body? I was told C Bodies have larger bearings inside? The races are the same. Just trying to piece this together.
 
The 1970 Kelsey Hayes are 11.75 in diameter and 1.000 to 1.010 thick. My bets your car had a drum to disc conversion done. Post some pictures of your calipers.
 
The 1970 Kelsey Hayes are 11.75 in diameter and 1.000 to 1.010 thick. My bets your car had a drum to disc conversion done. Post some pictures of your calipers.

I will do that. How does that explain the large bolt pattern on the rotors ? Wouldn’t they have a smaller bolt pattern if they were from an A Body?
 
I will do that. How does that explain the large bolt pattern on the rotors ? Wouldn’t they have a smaller bolt pattern if they were from an A Body?
A bodies went to the big bolt pattern in 73’
 
I will do that. How does that explain the large bolt pattern on the rotors ? Wouldn’t they have a smaller bolt pattern if they were from an A Body?

Is it possible that the steering knuckles are the same as A body but the calipers are different? The B body caliper is taller for a bigger diameter rotor?

It also would suggest both cars have been converted to disc. Either way I would like to know.

Thank you
 
Is it possible that the steering knuckles are the same as A body but the calipers are different? The B body caliper is taller for a bigger diameter rotor?

It also would suggest both cars have been converted to disc. Either way I would like to know.

Thank you
There has been a lot of conversions done. One thing for sure is not every conversion uses the same parts. Hence figuring it out can be a challenge. Posting some pictures may help identify what is being used.
 
This is a challenge to figure out. You’re right. A lot of time to change things around. I’ve had the charger since 1978 and it had the discs on the car. I’ll get some pictures of the calipers for sure.

Thanks
 
The big rotor is c-body. The small rotor should be 70-72 b-body, maybe they are 69 bendix stuff not sure on those.. In 1973 the spindle changed, and the rear bearing was bigger, the rotors became one piece also. 73 a-body spindles fit the early b-bodies and all e-bodies and have big bearings, they can also use 78-79 cordoba- magnum big rotors and caliper brackets.
 
The big rotor is c-body. The small rotor should be 70-72 b-body, maybe they are 69 bendix stuff nit sure on those.. In 1973 the spindle changed, and the rear bearing was bigger, the rotors became one piece also. 73 a-body spindles fit the early b-bodies and all e-bodies and have big bearings, they can also use 78-79 cordoba- magnum big rotors and caliper brackets.

The “small” rotors would be 11”?

The larger C body is 11-3/4”? The two different rotors have the same race and seal diameters.

That would mean if I have a 73 conversion the rotors installed on the cars would have bigger inside bearings?

I’m guessing the calipers/brackets will tell me what I need to know.

I’m curious if I changed the brackets would that allow the larger 11-3/4 rotors that should be on the car?

Either way I can tell you I never had brake problems stopping the car.

I would like to know for sure so that I can replace the rotors when I want and need to know what rotors to purchase.
 
The 1970 Kelsey Hayes are 11.75 in diameter and 1.000 to 1.010 thick. My bets your car had a drum to disc conversion done. Post some pictures of your calipers.
Not completely true in that reply.
1970 KH 11.75 diameter rotors were on the "C" body line of cars and were 1.250 inches thick.
B & E body, and 73-76 "A" body cars were 1.000 inches thick, most commonly referred to as the 10.8 inch rotor, or yes, 11 inch.
 
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Get into the 21st Century. There are replacement rotors for not a lot of money to replace the old 2 piece hub and rotor setup of pre 1972.
What year are the spindles on the 2 cars since you didn't give any specific info other than a " Charger" and a "RoadRunner".
 
Get into the 21st Century. There are replacement rotors for not a lot of money to replace the old 2 piece hub and rotor setup of pre 1972.
What year are the spindles on the 2 cars since you didn't give any specific info other than a " Charger" and a "RoadRunner".
That's not true.
Very little is available in the way of 70-72 rotors, for the cars to do a "replacement"
You most likely need to change the spindle, also, for a more modern upgrade.
Then your running into more $$$$$$ for the upgrade.
 
That's not true.
Very little is available in the way of 70-72 rotors, for the cars to do a "replacement"
You most likely need to change the spindle, also, for a more modern upgrade.
Then your running into more $$$$$$ for the upgrade.

I don’t know the year of the spindles since it seems like a conversion took place. I would need a way to identify to provide that to you. I can tell you they both have the same setup with 11” rotors I can give you pictures of the calipers and better measurements of the thickness. I seem to recall just over an inch which could be a later A body spindle judging from the previous post reply.
More details to come. Thank you
 
I have to agree here, 2 piece rotors belong on restorations. The factory changed to one piece rotors because of hub breakage. Hot setup for stock parts is 73 a or e-body spindles, 78-79 r-body one piece rotors and 78-79 r- body caliper adapters. Caliper adapters came in pin style and the later non pin, so to reuse your calipers you need to find pin style. Spindles and some adapters are reproduced, not sure if the big rotor caliper adapters are.
 
I don’t know the year of the spindles since it seems like a conversion took place. I would need a way to identify to provide that to you. I can tell you they both have the same setup with 11” rotors I can give you pictures of the calipers and better measurements of the thickness. I seem to recall just over an inch which could be a later A body spindle judging from the previous post reply.
More details to come. Thank you
If they are 2 piece rotors like your pictures they will be 1970-72 spindles.
 
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