Converting rear drum brakes from SBP to BBP
The UCA's have to come from a 73-76 A body equipped with disc brakes? Do all these models have the BBP?
No, not all of those models have the 5x4.5" pattern, only the disk equipped cars starting in '73. Drum cars still had the SBP. But, the control arms are the same. From 1973-1976 A-bodies used upper control arms with a larger ball joint than they did from 67-72.
On that note, you don't NEED to have UCA's from a 73-76 A-body. You can use tapered adaptors on the ball joints to match the 73+ spindles. The only difference between the 67-72 and the 73+ UCA's is the size of the ball joint. Doctor Diff sells the adaptors if that's the way you wan to go
Mopar A-Body Upper Ball Joint Tapered Adapter
I assume that the spindles, rotors and calipers must come from the same A body?
Nope. Mopar changed the spindle/brake package starting in '73, and they basically made it uniform across all the body styles except the C-bodies and trucks. It's pretty common to use FMJ body parts for this swap. The A-body spindles were slightly shorter than the E/B/R/F/M/J spindles, but the change in geometry is almost negligible. So, if you have a wrecking yard locally, you can check for all kinds of later cars on the F, M, or J platform. Diplomats had the right spindles for the swap up until '89 I think.
Swapping Disc-Brake Spindles - Mopar Muscle Magazine
Do all 73-76 A bodies use the 15/16" master cylinder? What other models should I be looking at?
No. Most of the A-bodies used a 1-1/32" master cylinder. The 15/16" I use is an aftermarket piece, also from DoctorDiff. I think the power brake A-bodies were the ones with 15/16" masters, but if you go manual the power m/c may not have the right cup on the piston for the push rod.
Why don't you like power brakes on these cars?
Because the pedal feel is terrible. Soft and squishy. Modulating the brakes isn't as easy as with manual brakes. And with a 15/16" master cylinder, pedal effort isn't that bad at all.
As for the rear of the car, any suggestions? I would like to come out with a larger diameter drum in the process.
What rear axle is in the car currently?
