1965 GTO Front Disk Brake Conversion
 

I want to add front disk brakes and a dual master cylinder to my 1965 GTO hardtop. Currently the car as the stock 4 wheel drum setup with power assist. I would like the conversion to look as though it was stock if Pontiac had offered disk brakes and dual master cylinder setups in 65.

To achieve that look I had planned to use a 1969-70 GM A-Body single piston caliper, 1967-1969 dual bowl master cylinder with 1.125" bore, frame mounted distribution block, metering valve mounted to the master cylinder, and a proportioning valve that is mounted in the rear, near the rear axle flex line connection.

My understanding is that a system comprised of these components replicates the setup Pontiac used in 1970 for the disk/drum brakes.

Some questions:
1) To achieve the proper brake bias I should replace my stock 15/16" bore rear wheel cylinders with the 7/8" bore wheel cylinders used on 1969-70 cars with front disk brakes?

2) Does anyone (e.g. Inline Tube) make pre-bent line kits that would work with the setup described above?

3) An alternative setup would be to use the all in one valve body that came out in 1971. However, most of the brake conversion kits I've seen have this valve mounted at the master cylinder, which I don't like. Is it possible to mount this all in one valve body on the frame, near where the stock distribution block used to be? If so, are there any pre-bent line kits that work with this configuration?

4) Will the use of either the dual bowl master cylinder distribution block or all in one valve mounted on the frame cause any interference with the stock "Z-bar" clutch linkage?

I very much appreciate your advice and suggestions about how to implement this disk brake upgrade.

Thanks!

Brad

Wish I could help you, after kind of stumbling through my own conversion on my 69 Lemans. Mine was a bit more factory than yours but I'm sure someone will step up to help. Good luck.

Hi 433lemans,

Thanks for the well wishes. I'm sure with a bit more research and some help from some folks on this forum who have done something similar, I should be able to pull this off.

Brad

I just did a similar conversion this spring on my 66 Conv. I got a kit from Ames so I could reuse my 14" Rally 1 wheels. I was very happy with kits. Disc brake, new springs, new front end bushings, Power booster and MC. All correct bolts provided. Good Luck. Ask questions.

I put front disks on my '67 GTO. I used a combo valve in place of the old distribution block on the frame and bent my own lines, I don't know if anyone makes a set of lines for the direct install. If you go for bending your own, use the nickel-copper tubing, very nice to work with.

George

On my 65 I bought a front disc conversion used a D52 type caliper.Used a 67 GTO dual MC and pushrod pulled the residual pressure valve from the front and just T for the fronts and got on down the road.

I think larger than 1" is going to be too big unless doing power brakes. Too much pressure will be needed.