A friend of mine has a 72 cutlass that has power drum brakes and he is thinking of changing the front brakes to disc brakes. Can he use the same spindles and put the disc on or does he have to change the spindles. Once he changes over to disc brakes does he need to install a proportioning valve?

 

The easiest way to convert to front disc, rear drum would be to find an early 70s Cutlass in a salvage yard with the parts on it. I know they were available. Then your friend can get all of the parts off of the salvage car and install them on his 72. Ultimately, I'm not sure if the early 70s A bodies had different spindles for front drum and disc brakes.

 

Yes you have to change the spindles, proportion valve, power brake booster, master cylinder, front rubber brake lines. If you can find an A body in the bone yard that would be the cheapest way, but you can buy a kit that has everything. Also when changing over to disc. Its a good time to change front coil springs if they need it since it will be all apart.

 

No, you do not have to change the spindles. HOWEVER they will need one additional bolt hole drilled and tapped to accept the caliper bracket (available aftermarket as well). I have heard that if you already HAVE a power booster, it does NOT need to be changed either. proportioning valve is available in the aftermarket catalogs.

now, with the costs involved, its better to get parts from a donor, or a kit.

John

 

[quote=Eightupman;120920]Not quite. The caliper bracket bolts to the existing holes. The problem is that you need to machine the boss around the upper bolt hole on the spindle. Here is some additional info (note that first gen Camaros use the same spindles as 64-72 A-body cars):

http://www.pozziracing.com/brakes.ht..._brake_spindle

Correct. I have done this swap several times keeping the existing power booster.

 

The disc brake spindle is taller which is beneficial for handling ...

This guy did a good job on his front end and I will update my spindle/ball joint set-up when I tear muh beastie down ...

https://classicoldsmobile.com/forums...tml#post117971

 

thanks to all that have replied it has been very helpful and will help guide my buddy in the right direction.

 

No, it is not. The A-body 67-72 disc brake spindles are IDENTICAL to the 64-72 drum brake spindles except for the height of the boss around the upper bolt hole. Go back and look at that link I posted above. The 77-90 B-body spindles ARE taller, but they are NOT a bolt-on swap.

 

(*0*) ...

I'm leaning toward tubular upper a-arm with a tall ball joint ...