Upgrading 73 `Cuda style disc brakes

Posted By: UCUDANT

Upgrading 73 `Cuda style disc brakes - 10/29/14 02:08 AM

I will be swapping an E body from front drums to 73 Cuda disc brakes and want to upgrade the system some. It's for a 500hp small block street car

I'm thinking a minimum of drilled and slotted rotors. Would it be worth using reproduction caliper adapters for the larger C body discs?

Posted By: RylisPro

Re: Upgrading 73 `Cuda style disc brakes - 10/29/14 02:19 AM

I would recommend any of Dr. Diff's kits and installing an adjustable proportioning valve.
I would highly advise against drilled rotors though, you will not need them for track use.

Here is a 13" rotor that Cass sells which recently showed up
Thanks Cass!

Posted By: RUNCHARGER

Re: Upgrading 73 `Cuda style disc brakes - 10/29/14 02:42 AM

If you're going to change rotors anyway I would upgrade to the C-body rotors for sure.

Sheldon

Attached picture 8314803-ChallengerBuild016.JPG

Posted By: RylisPro

Re: Upgrading 73 `Cuda style disc brakes - 10/29/14 02:59 AM

Another tip is to pay attention to the direction of the internal vanes the rotors have and to ignore the direction of the slots

I checked the one installed on my car and they go straight up and down while this new rotor I have is effectively a driver side rotor

Posted By: BigBlockMopar

Re: Upgrading 73 `Cuda style disc brakes - 10/29/14 01:41 PM

I've got 11.75" / 1.25" thick '73 Chrysler rotors on my '73 Dart.
Shimmed the original adapter with a simple washer to the correct caliper alignment and made a colar for the spindle to be able to use the stock '73 C-body outer bearing.

Quote:

If you're going to change rotors anyway I would upgrade to the C-body rotors for sure.

Sheldon

Are those C-body rotors in your pic? They don't look any thicker than 1" to me.

Posted By: ntsqd

Re: Upgrading 73 `Cuda style disc brakes - 10/30/14 03:25 AM

Rotor thickness is really just a rough idea of how well it will radiate heat with lots of other factors involved.

Rotor diameter is where better stopping power comes from. Bigger OD = more brake torque from the same hydraulics.

Posted By: amxautox

Re: Upgrading 73 `Cuda style disc brakes - 10/30/14 03:29 AM

Quote:

Are those C-body rotors in your pic? They don't look any thicker than 1" to me.

You think those are only 1" thick? The studs are 1/2" dia, compare those to the thickness. Sure looks like 1 1/4" thick rotor to me.

Posted By: UCUDANT

Re: Upgrading 73 `Cuda style disc brakes - 10/30/14 04:17 AM

After reading the above responses I started cross referencing wheel bearing PN's and it does appear the outer bearing is different.

What is the best solution for the wheel bearing to adapt the 73 E body spindle and the C body (73 and up?) rotor?Thanks for you input.

I'm already cleaning and prepping parts

THANKS

Posted By: AndyF

Re: Upgrading 73 `Cuda style disc brakes - 10/30/14 05:58 PM

There isn't really a clean way to hang a C body rotor on an E body spindle. You have to use spacers and hope they don't spin. I looked into having Timkin produce a conversion bearing but the cost was way too high for me to front.

Posted By: DoctorDiff

Re: Upgrading 73 `Cuda style disc brakes - 10/30/14 06:51 PM

I make outer bearing adapters for mounting '73 and newer C-body rotors on '73 and newer A/B/E/F/M/J/R body knuckles. They are no more likely to spin than the bearing itself.

You could also use '69-'72 C-body rotors, bearings and seals. These fit '72 and earlier B/E body knuckles out of the box.

If you install an A13 inner bearing and race, the earlier C-body rotors will fit '73 and newer A/B/E/F/M/J/R body knuckles without an adapter. I never looked into a seal for that combination, however.

Posted By: UCUDANT

Re: Upgrading 73 `Cuda style disc brakes - 10/31/14 01:32 AM

Quote:

If you install an A13 inner bearing and race, the earlier C-body rotors will fit '73 and newer A/B/E/F/M/J/R body knuckles without an adapter. I never looked into a seal for that combination, however.

Are they the 2 piece rotor/hub?
So the earlier C body outer bearing is the same as the 73 and up E body but it's inner is different?

Posted By: ahy

Re: Upgrading 73 `Cuda style disc brakes - 10/31/14 04:06 AM

The later 11.75" A/B rotor which fits (from memory) your spindles is a pretty stout piece. Suggest you use that. A good quality replacement rotor (parts store) should be fine. Newer formulation high po brake pads do not "out gas" much once broken in and I don't think slots or holes help much... and holes can start cracks.

Posted By: DoctorDiff

Re: Upgrading 73 `Cuda style disc brakes - 10/31/14 04:49 AM

Replacement '68-'72 C-body rotors are identical to the unicast '73 and newer version except for the bearing bore sizes.

The early C-body rotor will bolt to the early B/E body spindles using the original/same bearings.

Posted By: Mopar Mitch

Re: Upgrading 73 `Cuda style disc brakes - 10/31/14 08:30 PM

Dr. Diff -- For the 72-older spindles, using the 72-older larger C-body discs (and thus the 72-older smaller bearings, etc), are there special adapters needed for the calipers? Also, could light weight aluminum calipers, such as Wilwood (which part number?), be fitted accordingly? Mine is still 72-older spindles and stock calipers (actually, 72 calipers).

Attached picture 8317235-Mitch'sTA.jpg

Posted By: brads70

Re: Upgrading 73 `Cuda style disc brakes - 10/31/14 11:19 PM

Why not just us a C-Body spindle?

Posted By: cudazappa

Re: Upgrading 73 `Cuda style disc brakes - 10/31/14 11:22 PM

Quote:

You could also use '69-'72 C-body rotors, bearings and seals. These fit '72 and earlier B/E body knuckles out of the box.

What's the diameter of these rotors? Also, what calipers would you use in this case?

This is a really cool finding in this thread!

Posted By: DoctorDiff

Re: Upgrading 73 `Cuda style disc brakes - 11/01/14 02:51 AM

C-body rotors measure 11.75" x 1.25".

I make brackets that mate first generation Viper calipers, C-body rotors and B/E body drum knuckles.

Herman, who posted earlier in this thread, installed C-body rotors and pin type calipers on B-body knuckles using B-body 11.75" pin type caliper brackets.

Posted By: UCUDANT

Re: Upgrading 73 `Cuda style disc brakes - 11/05/14 03:39 AM

Quote:

Herman, who posted earlier in this thread, installed C-body rotors and pin type calipers on B-body knuckles using B-body 11.75" pin type caliper brackets.

On an E body? This is one that that tech editors disagree on

At this point I'm still not certain, there are allot of options. I'm considering all that it en-tales Is the extra 'close to an inch" of brake worth the effort? This is really all for a street panic stop

Dr Diff please PM me (or reply here) enough info so I can order your outer bearing (73 Cuda spindle to later C body rotors) adapter, once I locate the C caliper adapters. Thanks to you and everyone who provide parts we in the hobby truly need

Posted By: BigBlockMopar

Re: Upgrading 73 `Cuda style disc brakes - 11/05/14 10:58 AM

No E-body, but A-body, and using the stock '73 A-body knuckles.
An outer bearing spacer on the spindle and 2 washers behind the caliperbrackets was all I needed.

Oh and maybe the seals in the rear of the rotors which came from a GM transmission.

The C-body rotor swap also made the tracking width better, which is dearly needed on an A-body and wider wheels.

Posted By: UCUDANT

Re: Upgrading 73 `Cuda style disc brakes - 11/05/14 01:47 PM

So the C body rotor changes track width?

Posted By: BigBlockMopar

Re: Upgrading 73 `Cuda style disc brakes - 11/05/14 02:52 PM

Well I ment to say, not as wide as with a stock disc-setup.
Going to discs usually adds (unwanted) trackwidth (on an A-body).
I went from stock A-body discs to C-body discs and I recall to find the track to be a tiny bit narrower. I don't recall any numbers because I've been changing wheels and tires during that time aswell.

Posted By: DoctorDiff

Re: Upgrading 73 `Cuda style disc brakes - 11/11/14 03:58 AM

Yes. When using C-body rotors, the track width decreases about 1/4" per side when compared to '73 and newer A/B/E/F/M/J/R body rotors.