I just purchased a 74 Scamp. I want to convert from drum brakes to disks on front and rear. Looking for your experience with that, if you've done it already.

 

Those are relatively easy but could be costly. You'll need 4 rotors, calipers and master cylinder.
Summit I'm sure has a conversion kit. Your choice, but I would consider just doing the fronts.

1974 PLYMOUTH SCAMP Classic Performance A6374CBK-S Classic Performance 1963-74 Mopar Disc Brake Kits | Summit Racing

 

Thanks. Do you know what the largest rim is that you can get on a 74 is without a lift kit?

 

If you are changing from drum to disk I believe you will need a new proportioning valve to properly control front to rear. I did for my XJ which was disk on front and I just changed out rear drums for disks. May be different for drum/drum going to disk/disk, one of the smart guys here should be able to give input. I ordered one for pretty cheap from Jegs. When doing brake lines if you have to use adapters make sure they are full port. Don't ask how I know.

 

Sorry I'm not sure what size rim will fit. A speed shop should have that info.

 

I think the 74 was available with disks on the front. Buy the stock parts. What rear end do you have? If 8.75 there are plenty of kits to put disks on one of those. Buy a disk/disk master cylinder from a later car.

 

How is master cylinder different between disk/disk or disk/drum? I have done a few brake conversions and never had to change master cylinder, just the proportioning valve. I did have to change master cylinder to go from single piston caliper to a 4 piston.

 

Volume of fluid moved per stroke of the pedal. Disk calipers that a lot more fluid than a wheel cylinder.

 

My 68 Dart had factory non-power disk brakes. It wasn't stopping well. I checked and it had a drum brake master. I changed it out and it made a big difference.

 

For the rear you could swap out a rear axle assembly from a Jeep Liberty, it’s an 8.25 with disk brakes if you want the 5-4.5 bolt pattern and use spindles and brakes off a 74 Abody for the same bolt pattern…