Rear disc setup, helpful(?) information/tips

[rikkitik]

Just a few things I learned that I thought I would share.
The Challenger I purchased has rear disc brakes already installed by the previous owner. They were not set up correctly, so here is some info that may be useful.
The kit on the car uses Cadillac Eldorado rear calipers, (which are apparently common in this application). These calipers have a mechanical parking brake. Typical of rear calipers with mechanical parking brake actuation, the pistons DO NOT hydraulically "self adjust" as the pads wear. Parking brake use is required to actuate a ratcheting adjustment mechanism inside the caliper. One of the reasons the Eldorado calipers are popular for this application, is because the fluid displacement requirements are very similar to drum brake slave cylinders, which negates the need for a change to the master cylinder.
Somewhere in my car's past, the rear parking cable mounts were torched off, so no PB cables were installed by the previous owner. Because of this, the rear brake pads were barely making contact with the discs.
To correct the situation, I fabricated, and installed cable brackets.
I then bought a set of PB cables from Inline Tube, but they didn't/don't sell them with disc specific cables, I was told those must be purchased separately.
Yeah, well, it turns out you don't need to purchase the disc specific cables at all. The drum cables work fine if you remove the rubber grommet and return spring (wrapped around the drum end of the cable).
Also, in my case, the calipers were installed with brake pistons completely retracted. In that position, the internal ratchet would not work, even with the PB cables installed. I needed to rotate the piston 1/4 turn, to bring the piston out a bit (clockwise looking at the piston) then bolted the calipers in place. Two stokes of the parking brake actuation arm, (I could hear the mechanism clicking), the pistons/pads were extended to the proper position. Once set, the PB arm only moves about a quarter of an inch to apply the parking brake. I then attached the cables, bled the calipers, and was good to go.
Hopefully, some of this info is helpful to someone. 🍻

[Scooter]

^^^ Good info. Prior owner installed similar setup on mine... Ebay purchase. I contacted the seller to get the info so I could get replacement parts if needed.

Here is essentially what they use in these kits:

85 Eldorado calipers and pads-1985 Cadillac Eldorado
79 Trans Am rotors with dual bolt pattern- 1979 Pontiac Trans Am

Also, if you are using the stock wheels you will likely need to do some filing on the backside of the caliper casting as there is some interference. I'll post up some photos if I can findem'.

[MOPAR MITCH]

Good info.    What did you do about the proportioning valve body?

(I recently installed a DrDiff 10.75" rear setup... had some surprises... drivable but still not done ... proportioning valve body to be gutted).

[rikkitik]

Good info.    What did you do about the proportioning valve body?

Mine has a manually adjustable, external, proportioning valve. Just a matter of adjusting front to rear balance. The original brass valve body is still on the car, but I haven't explored it's guts.
Did you speak to Cass at Dr Diff? He should be able to help you sort it out.
Also, minor side note. Eldorado's used identical pads f&r, EXCEPT that the fronts have the "anti-rattle" spring clip. Most "over the counter" pads have the clip riveted in place (which can be ground off). If you want them without the clip (true rear pads) "they" will probably need to be ordered. NAPA sells the same pad for f&r with manually installed clips. So they usually have them in stock. Just leave the clips off, one less thing to have to screw around with.

[Cuda70-74]

Im using some 2011-14 mustang rear calipers on mines