Who has Dr. Diff 8 3/4 rear discs?

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Dr Diff cables are different sizes at either end. Be aware of that. One side will fit the caliper hole. If it doesn't? The other end will. Ask me how I know?
 
I'm very impressed with the overall design of the Rear Disk kit. I've been in R&D for one of the Big 3 auto companies for over 40 yrs.
 
I'm sure I'm late to the party on this one from the sounds of it. But I am running the Dr Diff rear kit on my Duster and everything appears to be working correctly, WITHOUT a parking brake setup. I have an adjustable prop valve for the line going to the rear, but I am running it at wide open with his 15/16" Master. The car brakes pretty well and the fronts lock up just before the rears.

I have wondered if a parking brake setup was needed to keep them adjusted properly, but I have never used my parking brake on my daily driver to adjust the rear brake pads, so I figured it wasn't needed. Am I incorrect with this setup? I would like to install an e-brake, but have not a single piece of the system currently.
 
72Duster440 said:
I'm sure I'm late to the party on this one from the sounds of it. But I am running the Dr Diff rear kit on my Duster and everything appears to be working correctly, WITHOUT a parking brake setup. I have an adjustable prop valve for the line going to the rear, but I am running it at wide open with his 15/16" Master. The car brakes pretty well and the fronts lock up just before the rears.

I have wondered if a parking brake setup was needed to keep them adjusted properly, but I have never used my parking brake on my daily driver to adjust the rear brake pads, so I figured it wasn't needed. Am I incorrect with this setup? I would like to install an e-brake, but have not a single piece of the system currently.
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I don't have a prop valve, just the 15/16 master and drum distribution block. With the rear in the air the piston doesn't extend far enough to completely stop the wheels (they will slow)

The car does stop idling down the driveway, not sure at speed.

Based on this I believe a park brake is required to adjust the rears correctly.
 
The Dr diff rear kit I ordered has a small drum built into disc assembly!

I had one of those cheap Chinese kits rear disc setup and it said in instructions that the lever on caliper must be cycled thru one of more times BEFORE bleeding. Also that Parking brake must be USED EVERYTIME you park to keep piston pressing against rotor when it needs to.

Hope this helps in some small way !
 
cudamike13 said:
The Dr diff rear kit I ordered has a small drum built into disc assembly!

I had one of those cheap Chinese kits rear disc setup and it said in instructions that the lever on caliper must be cycled thru one of more times BEFORE bleeding. Also that Parking brake must be USED EVERYTIME you park to keep piston pressing against rotor when it needs to.

Hope this helps in some small way !
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What kit did you get? I wasn't aware he had a different one with a different caliper. Either way, I got it all hooked up and adjusted. Gonna re bleed tomorrow.
 
I have the 10.75 kit. No built in drum brakes in my kit. Just a E brake cable to pull on the caliper spring.
 
I'm not sure, I haven't received it yet. I don't remember except that parking brake is built into disc as a drum. I received new cables from him,, they look awesome.
I'm pulling the cheap chinese crap and probably just give it away. (not really, but will go real cheap.)
 
I just did some looking, I bought the 11.25" rdb kit. Website pic (dr diff) clearly shows drum as parking brake in 11.25" kit.
Don't know the other as mine is a 67 Barracuda with 8 3/4.
I am getting 11.75 fdb kit , to finish up my suspension and get on to finishing my car!!!
 
My 11.7” DoctorDiff kit definitely doesn’t have any kind of drum. It’s a Mustang cobra rear caliper set up.
 
cudamike13 has the 11.25" kit that uses Ford Explorer calipers and they do have a drum emergency brake set up inside the rotor.
 
oi81b4uu812b4 said:
cudamike13 has the 11.25" kit that uses Ford Explorer calipers and they do have a drum emergency brake set up inside the rotor.
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Mopar 11.25" Rear Disc Brake Kit

huh, well look at that. I didn’t realize DoctorDiff had a new rear brake kit out, used to be just the 10.7 or 11.7’s and those both used mustang calipers. Yup, that 11.25” kit definitely uses a drum brake.
 
Anyone else have an issue with the Dr Diff Ford caliper kits having the powder coating delaminate and chip off easy?

They don’t look like they got pre baked.
 
oi81b4uu812b4 said:
Anyone else have an issue with the Dr Diff Ford caliper kits having the powder coating delaminate and chip off easy?

They don’t look like they got pre baked.
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I assume you mean the explorer calipers for the 11.25” kit?

DoctorDiff uses several Ford calipers, I haven’t had any issues with the powder coating on the Mustang cobra calipers on the 11.7” kit.

8F03F250-74E9-4260-BEE0-4FC6F6E86EA1.jpeg


Or the cobra calipers on his 13” front disk kit either. They’re dirty but the powder coating is fine.

CE979212-8803-4ACD-B577-659E86BC8C6E.jpeg
 
Nope. I have the 11.7” just like you. Anywhere you touch the caliper the powder coating comes off in huge flakes. Most likely will have to get them prebaked and redone.

And not all aftermarket pads work in these calipers. The one that come in them are thin. Just keep that in mind.

D96631D4-21B9-4C19-A964-E597B0EF07D8.jpeg


025C19A0-3DED-44C6-B111-F2FCF8BA9FD2.jpeg
 
Huh. Maybe just a problem with the red ones?

What color are yours @72Dart6pack?

Pads seem plenty thick, this was before install. But I haven’t been running them long enough to need to replace anything.

B0349435-312C-4F7F-9AE9-E5C177944208.jpeg
 
plumkrazee70 said:
Did you have a problem bleeding them?

I have his stage 1 rear disc kit with the mustang calipers, his 15/16 MC and his 73+ A body front discs on my 70 Dart with a drum distribution valve.

When the car is jacked up in the rear, idling in gear, I cannot get the rear wheels to stop when I push on the brake pedal. The wheels will slow, but won't stop.

I have bled them all along with the master, but I am out of ideas. I don't have parking brake cables, but did actuate the lever about 2 dozen times before bleeding. I haven't tried holding the lever (applying the parking brake) while bleeding, yet. I am getting fluid to the rear and can NOT turn the wheels by hand, if either brake or park brake is applied.

When the car is in the ground, it will stop if the car is idling in drive, but haven't tried it at any kind if speed.

Any thoughts?
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No problems whatsoever with the kit itself. It went on really well, no problems bleeding them. You are better off getting everything from Dr Diff, his E cables and everything else is top notch.

My only issue is the powder coating is flaking off way too easy. Obviously the calipers didn’t get pre baked to get all the oils off the bare castings.

I have heard that some people can’t get the stock distribution blocks to work after messing with them...

If I ever have problems bleeding a new caliper, I usually end up cracking the bleeder over night... If that doesn’t work, I Clean them out and sometimes put a new rebuild in them.
 
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oi81b4uu812b4 said:
No problems whatsoever with the kit itself. It went on really well, no problems bleeding them. You are better off getting everything from afar Diff, his E cables and everything else is top notch.

My only issue is the powder coating is falling off way too easy. Obviously the calipers didn’t get pre baked to get all the oils off the bare castings.
Click to expand...

I got everything from him. The parking brake is on and adjusted. I'm gonna re bleed them to be sure. I was too tired last night.
 
Sorry it took so long to update this thread. Ive been super busy with other parts of the car. Finally got the headliner and glass in. However, still have the same problem with the rear brakes. I am going to start another thread on it. I have pics and a video.
 
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