Rear disc brakes - Cobra kit from Dr Diff

We use that kit on our 24 Hours of Lemons car and it works great. It was originally on our 4000 pound 67 Fury and at it's last race we were going from 130 MPH to 60 MPH at the end of the straight at Spokane and it never faded once. We have 73 C-Body discs on the front with 4 piston Viper calipers. We have the same brakes now on our 64 Barracuda Lemons car. Of course with the 170 ci slant 6 we can't get it to go fast enough to even warm the brakes up!

What size are the rotors?

What does a kit like this cost? Looks to be well thought out.

DoctorDiff
master


Reged: Jan 20 2003
Loc: Polson, MT
Re: Mopar Differential For Sale - May [Re: moparts]
#7689832 - Wed May 01 2013 09:17 AM
Reply Quote

ALL NEW PARTS FOR SALE:

MO-400, snap-ring Green wheel bearings $65 pair

OEM Timken set 7 wheel bearings with all gaskets and seals $90 pair

New high-strength 30 spline 8 3/4 axle package. Most lengths. Includes green wheel bearings and standard length lug studs installed. $300 pair. Choice of standard length, or 3" lug studs.

New high-strength 35 spline Dana 60 and 8 3/4 axle package. Most lengths. Includes green wheel bearings and 2" or 3" lug studs installed. $300 pair

New 8.75" power-lock (clutch) sure-grips. These are not the same units offered by others. I blueprint the clutch tension with hardened shims I produce. $375

New ring and pinions for 489 casting (29 spline): 3.55, 3.73, 3.91, 4.10, 4.56 $185

New US/Strange ring and pinions for 489 casting (29 spline) 3.55, 3.91 Very consistent quality: $205

New ring and pinions for 742 casting (10 spline):
3.23 $225
3.55 $200
3.73, 3.91, 4.10, 4.56 $185

New ring and pinions for 741 casting (29 spline):
3.55, 3.73 $185

New ring and pinions for Dana 60 (29 spline):
3.54, 3.73, 4.10, 4.56 $195

Bearing/seal/shim kits Timken:
8 3/4 489 castings $100
8 3/4 741 castings $115
8 3/4 742 castings $115
Dana 60 $125

Bearing/seal/shim kits Koyo:
8 3/4 742 castings $100
8 3/4 489 castings $85

Bearing/seal/shim kits Timken:
8 3/4 742 castings $115
8 3/4 489 castings $100

489 casting billet steel pinion bearing spacer kit with shims. Eliminates troublesome crush sleeve $30

1350 U-bolt yokes 29 spline Dana 60 FORGED STEEL $70 each

1350 U-bolt yokes 10 spline 8 3/4" FORGED STEEL $70 each

1350 U-bolt yokes 29 spline 8 3/4" FORGED STEEL $70 each

7290 U-bolt yokes 10 spline 8 3/4" FORGED STEEL $70 each

7290 U-bolt yokes 29 spline 8 3/4" FORGED STEEL $70 each

Repro, cast 7290 strap yokes 29 spline Dana 60 $120

35 spline Dana 60 spools (3 or 5 series) $125

35 spline 8 3/4 spools $115

30 spline 8 3/4" spools $100

New, nodular iron 8 3/4" 742 castings with heavy duty forged steel caps and billet steel adjusters $300

New, nodular iron 8 3/4" 489 castings with forged steel caps and billet steel adjusters $300

DoctorDiff E-body 1" offset spring hanger/shackle kit for standard springs. Can be used to bolt B-body rearend into E-body with no modifications $175

DoctorDiff Challenger 1 1/2" offset spring hanger/shackle kit for standard springs $175

DoctorDiff E-body 1" offset spring hanger/shackle kit for Superstock springs. Can be used to bolt B-body rearend into E-body with no modifications $185

DoctorDiff ‘71-’74 B-body 1 1/4" offset spring hanger/shackle kit for standard springs $185

DoctorDiff A-body 1/2" offset spring hanger/shackle kit for stock springs (1/2" front eye hole) $150

DoctorDiff A-body 1/2" offset spring hanger/shackle kit for heavy-duty aftermarket springs (5/8" front eye hole) $150

Aluminum master cylinder package. Kit includes 1 1/32" bore master cylinder with level reservoir, billet aluminum adapter and push rod retainer. Correct bore for most Mopar musclecars $95

Aluminum master cylinder package. Kit includes 15/16" bore aluminum master cylinder, line fittings, billet aluminum adapter and push rod retainer. Used for brake systems that require maximum line pressure $100

DoctorDiff Hemi brake booster assemblies:
Complete assemblies with brackets, linkage, rebuilt booster and master cylinder:
1. With Hemi bolt pattern Bendix booster $1000
2. With Wedge bolt pattern Bendix booster $850

DoctorDiff Hemi brake booster brackets:
Kits include brackets, linkage, retaining plates, push rod boot and hardware (no booster):
1. Hemi bolt pattern Bendix booster $250
2. Wedge bolt pattern Bendix booster $250

Hemi Booster kits available for:
1. ‘66-’70 B-bodies
2. ‘71-’74 B-bodies/’70-’74 E-bodies (add $35 for firewall stiffening plate)

DoctorDiff 13" front disc brake kit includes loaded Cobra calipers, steel caliper brackets, drilled/slotted/plated rotors, hubs, bearings, seals, dust caps, stainless flex lines and hardware. All new parts $850
Please specify:
Kit A: '73-Up A/B/E/F/J/R body disc knuckles
Kit B: '70-'72 B/E body disc knuckles
Kit C: '62-'72 B/E body drum knuckles
Kit D: '73-'76 A body drum knuckles

DoctorDiff 10.7" econo rear disc brake kit includes loaded Cobra calipers with internal parking brake, 2 piece steel caliper brackets, rotors, stainless flex lines and hardware. All new parts $525

DoctorDiff 11.7" rear disc brake kit includes loaded Cobra calipers with internal parking brake, billet aluminum caliper brackets, drilled/slotted/plated rotors, stainless flex lines and hardware. All new parts $650

DoctorDiff NEW reproduction 11.75" cast iron caliper brackets $90 pair with bolts

I take PayPal, Visa, MC, Discover and money orders.

doctordiff@gmail.com

(406)883-4772

We run that kit on Tim's Valiant. With the new 427 inch small block Tim's car runs 150-160 mph at Portland International. The brakes get used pretty hard at that track.

I'm curious if the rear disc setup from Dr. Diff changes the rear track width... by any width at all??? I'm leaning towards eventually gettin the econo ~10.57" setup.. so they will still fit inside my 15" vintage minilite rims that I use for the street/hwy cruising.

A few weeks back I ran into a rear end brake lock up issue posted here. A quick solution was just to dump my OEM tapered axles and go with a dr diff small disc/axle package with an e brake. Seems like a decent solution, my application is low performance cruiser only, but with my aftermarket 14x8" wheel package, that I really want to keep, the 3/16" added width per side with the disc kit, is putting solution on hold. I am already barely rubbing. One solution for me is to lath cut wheels for more back space. I'm currently at a standstill.

I'm thinking about trying this kit on an R&D car. Better get the sledgehammer back out.....get them fenders a bit wider.

I have them on my b-body width Dana in the Challenger. They work great, I have an adjustable p-valve plumbed in but never needed to use it. He uses 89 Toyota Cressida rotors. I sourced my own rotors so they matched my front ones.




HD tapered bearings and retainers...

I make 2 different versions.

The 10.7" kit uses Toyota Cressida rear rotors.

The 11.7" kit uses Mustang Cobra rear rotors.

I recommend the 10.7" kit for 15" wheels and the 11.7" kit for 17" and larger wheels.

Project black n blue-the 1970 Charger RT has the Dr Diff cobra brakes on the rear and the large mopar rotors on the front with the wilwood calipers. No problems with this set up on or off the track.

This braking set up work very, very well on the road course on a big fat heavy car. Good enough to outbrake a Challenger SRT and many other cars...and not be red hot after 45 minutes of laps

Just a reminder that all braking systems put under duress require air ducts whether its a 70 foot slalom or hot laps on thunder road.

We more than likely are going back to the track [Watkins Glen] with a new Cope transmission/converter, turbo action shifter, real track tires and some new hardware [shhh it's a secret] on the suspension that should improve the handling yet not increase the ride harshness.
I can't talk about the aero tricks either...yet.

This will also be a good test of the braking/suspension systems for sure as lap times will drop and brake temps go up. We will be running the NASCAR course in the afternoon so it will be really interesting to see how well ole big fat n happy black n blue performs.

I've been using the 11.75 kit since 2006! Now with 14" fronts and viper gen threes, braking is fun. On the track I see others struggle to haul down from the straights....

I've got Cass' kits on two of my cars. I replaced a crappy setup that used older Caddy Eldorado calipers. Although the pad size seemed a little small they work well and I don't have a proportioning valve in the system. Feel, with power brakes was greatly improved with an A-body disc brake master versus the 2-bolt "truck" 1-1/8" bore master cylinder with plastic reservoir.

Looks good ! Did you need to add a spacer,? I almost went with the 11.7" kit but the tolerance seemed a tad close, im running 15"torque thrust D rims as well.
No complaints the 10.7's seem to work very well. Im running the Viper front setup as well. Manual with a 15/16 master. Works well. Great pedal.



Ron

Does anyone have tips on how to install the Dr Diff 11.75 brakes?
I got my kit and am going to install it but I have never pulled the axles or swapped to rear dics before
I am sure it is not rocket science and should not be too hard, just wondering on the torque specs on the bolts used, etc.

I have seen instructions on other brands of rear brake kits but not Dr. Diff's
http://www.tsmmfg.com/2160.html
http://www.moparts.org/Tech/Archive/brake/8.html

thanks

Dr Diff was awesome in helping me spec out what I needed and, most importantly, was there for follow up. I emailed him many times late at night with a question and he emailed me back within minutes which kept the project going that night. Knowledge and follow up made it worth it alone. Just my 2 cents.