All, My mom is the original owner of a drum brake non-power ‘65 Special. A year ago she had it converted to power brakes, and at the same time for the sake of safety the single chamber master was replaced with a tandem master. The brakes are now far too good! Modest pedal pressure is enough to throw you through the windshield. I suspect the master that was installed has far too much piston area, and is designed for disc/drum versus drum/drum. I can’t seem to find a tandem master for drum/drum applications. Can somebody point me in the right direction? Thanks!
https://www.amazon.com/Raybestos-MC...e=UTF8&qid=1547451846&sr=8-1&keywords=mc36373 This is for a 1962-1966 Cadillac, they had a dual circuit, power brake, 4 wheel drum brake system before most other GM cars. There is also the depth of the hole in the piston for the rod coming out of your power booster to consider. It has to fit properly. The replacement boosters I have bought in the last few years, new and rebuilt, have come with 2 different length rods to use. I also call attention to Auto Zone website which clearly say the application for the master cylinder on a 1967 Buick Skylark with front disc and one for front drum. That also should work. Best luck
A power brake system has a larger piston then a non-power system. If it's too touchy maybe the master cylinder is too small.
Yes but a disc/drum system uses a much larger piston than a drum/drum system. The current master piston is way too large. There is almost no pedal movement before you are thrown through the windshield, and the pedal is very firm. A smaller master bore will deliver a longer pedal stroke and a softer pedal, both of which are desperately needed. A drum/drum master is what I need....
I had my '65 Sportwagon updated to a dual master cylinder a few years ago. It started out as a power brake car, and the master used was spec for a drum/drum '67 Impala. Worked perfectly: braking performance, pedal feel and travel all perfectly normal. Windshield still intact.