Need Brake Expertise to Identify Rotors

[Road Grabber]

If they are 2 piece rotors like your pictures they will be 1970-72 spindles.

The painted black rotor in the photo is a two piece?
If so do you know if I can get replacement rotors?
Can 1970-72 spindles that receive 11” rotors bolt on different caliper brackets to place the larger correct 11-3/4 rotors?

Just looking at all options if I keep these spindles on the cars. My biggest concern is to be able to replace a rotor that is too thin if I need to. The existing setup does stop the car fine but I don’t want to keep it if I can’t get replacement rotors.

If I can bolt on a different caliper bracket to enable larger rotors like the service manual says then I would do that.

I will have to look into the spindle swap for the “hot setup”. Is it something easy to locate? Can be outright purchased? Etc because the spindles are off the car on the road runner and now would be the time to do an upgrade. I don’t want to swap spindles and risk damaging ball joints/boots to do it later.

Thank you for the help

 

[pnora]

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.

The 1970 factory FSM states them as I said.

 

[4406bbl]

The painted black rotor in the photo is a two piece?
If so do you know if I can get replacement rotors?
Can 1970-72 spindles that receive 11” rotors bolt on different caliper brackets to place the larger correct 11-3/4 rotors?

Just looking at all options if I keep these spindles on the cars. My biggest concern is to be able to replace a rotor that is too thin if I need to. The existing setup does stop the car fine but I don’t want to keep it if I can’t get replacement rotors.

If I can bolt on a different caliper bracket to enable larger rotors like the service manual says then I would do that.

I will have to look into the spindle swap for the “hot setup”. Is it something easy to locate? Can be outright purchased? Etc because the spindles are off the car on the road runner and now would be the time to do an upgrade. I don’t want to swap spindles and risk damaging ball joints/boots to do it later.

Thank you for the help

Any 73-76 a-body spindles will work, I see them for sale on ebay all the time, and they are reproduced. 78-79 r -body rotors are easy to find at any parts store. Caliper brackets are not that hard to find, ebay, wanted add on this board or your local junkyard, any cordoba or magnum. You can even buy viper calipers and caliper adapters to be even cooler. Google mopar action disc-o-tech. Call doctor differential and see what he has, there may be bearing adaptors to fit your spindles. I am not a fan of them, and there is a set of spindles for sale for $69 on the internet right now. Doc different has caliper brackets for $90, rotors are $92 a pair. 5 minutes of search and you are set.

 

[pnora]

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.

This is from my 1970 Charger B-Body FSM.

 

[hemi71x]

This is from my 1970 Charger B-Body FSM.

View attachment 1312753

That maintenance manual is in error.
Either the diameter is a miss print, or the width is a miss print.
In the real world, there is NO 11.75 inch rotor for a B body car that measures at 1.000 - 1.010
11.75 rotors are C body.
Your going to hafta go out into the real world and find that out for yourself.
But i do see where you think your getting your information from.

 

[4406bbl]

He is right.

 

[Road Grabber]

If that’s the case then what is on the car is correct because it’s 11”. The charger manual specifications is what confused me. Especially since the measurements of the rotors on the cars match the Dart brake rotor specs.

I took pictures of two other rotors I thought might be the correct charger rotors but must be C body rotors. They measure 11-3/4 and are 1-1/8 thick. The NOS rotors I have must be the C body rotors too yet both of the large rotors have different minimum thickness specs. One is 1.180 min and the other is 1.200.

These photos include the spindle and caliper on the 70 road runner.

Thank you for all the replies.

 

[Road Grabber]

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.

Is the rear bearing a bigger diameter in 73 or is the race the same but the spindle hole is bigger? I ask because the C body hole in the rear bearing was larger but the race diameter was the same.

 

[hemi71x]

I once wanted to figure out what the heck the difference is between a 70-72 race and bearing, and a 73 up race and bearing.
Why they wouldn't work, in changing them around.
My observation was the diameters of all the rollers that make up the full bearing are of different diameters.
The 70-72 bearing is made up of smaller diameter rollers, and the 73 up bearing is made up with thicker diameter rollers.
That make scene to you?
They don't interchange between the two rotors.
I tried.
Doesn't work.
70-72 Spindles, bearings, rotors.
73 Up Spindles, bearings, rotors.
Each onto their own.

 

[Road Grabber]

I once wanted to figure out what the heck the difference is between a 70-72 race and bearing, and a 73 up race and bearing.
Why they wouldn't work, in changing them around.
My observation was the diameters of all the rollers that make up the full bearing are of different diameters.
The 70-72 bearing is made up of smaller diameter rollers, and the 73 up bearing is made up with thicker diameter rollers.
That make scene to you?
They don't interchange between the two rotors.
I tried.
Doesn't work.
70-72 Spindles, bearings, rotors.
73 Up Spindles, bearings, rotors.
Each onto their own.

That makes sense and helps very much thank you. If I want to keep what I have I have to find a replacement rotor for a 70-72 spindle.
And the rotors are 11” diameter and 1” thick?

The 73 up rotors are same diameter but use different spindles with larger rear bearings? Have I got it?

I want to find good replacement rotors if possible. If no one makes them I will have to switch to the 73 spindle setup.

 

[hemi71x]

for MOPAR B, E-body Front Disc Brake ROTOR KIT 1970-'72 Dodge Plymouth Cuda Chgr | eBay

ebay.
WOW


Don't want to influence you one way or other in your decision(s) but i have spindles advertised over on the A bodies site.
[FOR SALE] - **DISC BRAKE SPINDLES** 73-76 A Body Cars & 73 74 E Body Cars.

 

[4406bbl]

Is the rear bearing a bigger diameter in 73 or is the race the same but the spindle hole is bigger? I ask because the C body hole in the rear bearing was larger but the race diameter was the same.

Not sure on bearings but once I saw the bigger spindle and better hub I never used anything else, plus it was cheap to do.

 

[Road Grabber]

So I decided to keep the road runner brakes original and go with the updated discs for the charger since I am going modern front suspension and revamping 440 six pack with I hope over 500hp. Not worried about original since I am updating the front suspension.

Here's the situation that maybe you brake professors might know the answer to...

I bought replacement inner and outer bearings/races for the 70 spindles on the road runner. Both of them fit and are installed on the car. The application given to Napa was 1970 Dodge Charger with front disc brakes.

I needed bearing cover cups and I went to install them only top find out they were too small. Napa says that's what the book says and I believe him because I checked Rock Auto and they list the cup diameter to be 1-9/16 which is way too small. I measured the existing bearing cup and it was 1.780.

I went back to Rock Auto and checked what the bearing cup diameter is for a 1973 Dart disc brake rotor and it was 1-13/16 which I think will fit since they are a press fit and are relatively soft to do so.

Why on earth would the bearings and race be correct in the book for the 1970 rotors but the bearing cup parts are wrong? - too small? I thought in our previous conversations that the newer Darts had the same front bearing diameter but the inner bearing was larger?

You think this is all because of false part listings?

This has me "DISC"cumbibulated....

I ordered the 1973 Dart cups and will see if they fit tomorrow.....

 

[hemi71x]

Because these days, in this modern day and age, the machining tolerances between auto parts manufacturers are vastly different between one another.
You get one company making grease caps, and another making rotors, and others bearings and races.
Then you probably don't get companies making parts in China, converting size, from American standard, to Metric, in the machine shop world.
I got a box full of OEM grease caps, out in the garage.

 

[Road Grabber]

Because these days, in this modern day and age, the machining tolerances between auto parts manufacturers are vastly different between one another.
You get one company making grease caps, and another making rotors, and others bearings and races.
Then you probably don't get companies making parts in China, converting size, from American standard, to Metric, in the machine shop world.
I got a box full of OEM grease caps, out in the garage.

I can’t drive the car right now because of a stupid grease cap. I just tested the new grease caps that wouldn’t fit up against the dynamic friction rotors I planned to use for the charger and they fit. This was the 1973 dart application.
I’m calling dynamic friction tomorrow and want to know if they sell the seals, bearings and cap as well. Then be done with it. What a waste of time.
The Napa cups are much too small they said were for 1970 disc brakes. 1-9/16. Not even close but yet that’s what rock auto says is correct. I have a suspicion that the races Napa gave me are too tall and won’t let me press the caps in. Gonna check that out later. First I had to get my motor back together.

What another China parts mess.

 

[Dragon Slayer]

Just to be clear the 67-69 B body used a bendix system and the rotors are different, but still 2 piece. The 67-69 b body rotor were 11.19" dia. with .880 thickness. The A bodies used KH Disc in 69 they were 11.04" dia and .810" Thick.

The 1970 system was KH for B and E from 70-72. The disc was 10.98" dia. 1" thick. These are small spindle bearing. You can't mix rotor between systems. If you read the service manual it spelled out the B body disc as 1.0" and the Fury as 1.25" thick. The spec page was wrong. I think if you have the service manual for E Body it may spell out the correct specs. Not sure.

All these started as 2 piece units.

Centrix was selling single piece 70-72 B&E body replacements at one point. I have them on my road runner.

Mixing doesn't work because of back spacing of the hub, the disc doesn't line up with caliper. Example using a 70 rotor on 69 set up and vice versa. And a thick rotor clearly won't work on a set up requiring a thinner rotor.

 

[Road Grabber]

Just to be clear the 67-69 B body used a bendix system and the rotors are different, but still 2 piece. The 67-69 b body rotor were 11.19" dia. with .880 thickness. The A bodies used KH Disc in 69 they were 11.04" dia and .810" Thick.

The 1970 system was KH for B and E from 70-72. The disc was 10.98" dia. 1" thick. These are small spindle bearing. You can't mix rotor between systems. If you read the service manual it spelled out the B body disc as 1.0" and the Fury as 1.25" thick. The spec page was wrong. I think if you have the service manual for E Body it may spell out the correct specs. Not sure.

All these started as 2 piece units.

Centrix was selling single piece 70-72 B&E body replacements at one point. I have them on my road runner.

Mixing doesn't work because of back spacing of the hub, the disc doesn't line up with caliper. Example using a 70 rotor on 69 set up and vice versa. And a thick rotor clearly won't work on a set up requiring a thinner rotor.

Thank you.

Two questions...

1. Do they all share the same front outer bearing size?

2. If so, do they all use the same bearing cup? The NAPA and RockAuto show a 1-9/16 bearing cup for a 1970- charger. They are too small.
I must have the right rotors because they are two piece and and don't have a larger inner bearing/seal. Yet when I order a bearing cover they insist the charger uses a 1-9/16 bearing cover. The bearings and seals they sold me fit. The cups that are supposed to fit don't fit.

The bearing cover that comes close is a 1973 rotor Dart bearing cover.

I just received two Dynamic Friction rotors that are the correct part number for a 1970 charger replacement. The 1973 bearing cover seems to fit. I chatted online with Dynamic Friction and they won't tell me what bearings, seals and cup fit their rotors. Terrible support just because I didn't buy the rotors form them? They wouldn't tell me and they don't sell the bearings and seals for their rotors - which are made in China! So I said why would I buy your rotors even from you if you can't tell me what bearings and seals to buy....crickets......

I can't drive my car because of stupid bearing cups I need. The originals need replacement.

 

[Dragon Slayer]

The 70-72 KH disc used the A2 outer and A6 inner I believe. Rock Auto has them as sets.

 

[Road Grabber]

The 70-72 KH disc used the A2 outer and A6 inner I believe. Rock Auto has them as sets.

Thank you.
A2 and A6? Not very long part numbers,,,..

I will check it out. Thanks.

 

[Dragon Slayer]

Just checked my leftover in box. Look up the Timken one, it also gives the part number for the race and bearing. Rock Auto click on the Timken info page and you will get the info you need. Believe A2, 3, 6 etc... Was nomenclature for the bearing size. Timken box had SET2 and SET 6 labels, plus the longer part number.

I also have a set of rotors vintage from the day solid one piece, in excellent condition with the races installed if you need them. Did not realize they went out of stock on the 70-72 rotors. Calipers used to be readily available at local parts store too. These rotors were pulled from an E body that was converted to a race car.