Does anyone have any experience replacing rear drum brakes on 1974 Delta 88 with disc brakes? My car will never be a show car but a fun cruiser. Is there a benefit to making this conversion.

 

Welcome to our site. If your car has good braking now just let it go. My family daily driver is a '99 Buick LeSabre with front discs and rear drums and it works fine for us. Lots of cars are set up like that.

 

You won't find a low-dollar kit, if that's what you're asking. You can adapt the rear disk brakes from a 91-96 Caprice or Impala SS. These cars have the same 5 x 5" bolt circle as your 74 and are still relatively common in wrecking yards (though not all got rear disks). Look for taxis or police cars, primarily.

You will need to pull the axle shafts from your current rear to remove the drum brake backing plates. The disk brake backing plates and caliper brackets may require some grinding to fit on your axle housing. The rotors will need to pilot on the raised center of the wheel flange on the axle shafts. If the hole in the rotor is too large, you will need to have spacer rings machined. If the hole is too small, you should have the axle flanges machined to fit so you can use stock replacement rotors.

Note that you will need a disk/disk master cylinder and a different proportioning valve, likely an adjustable one.

 

Thanks for the technical answer on that one Joe. You know me, I just have to welcome everyone if possible and try to "take a stab" at some semblance of an answer.