I was wondering if anybody knew, i have a 1959 oldsmobile 88, and it still has the original style single master cylinder, and while it works well, its the first car ive ever had with a single master cylinder, and i dont like the idea of having one tiny leak anywhere in the system being all thats between me and the rest of the world. I was wondering if somebody knew, is there a tried and true, dual master cylinder i can buy thats from a different year oldsmobile car, or GM car, that will bolt directly in place of the single master cylinder? and then i guess all i would need is a proportioning valve and some brake line to pipe into the existing lines? I dont want to get into fabricating something, and would like something normal, stock, and cheap, that will just bolt up. The master cylinder on it has 4 mounting bolt holes, instead of the traditional 2 bolt holes most cars seem to have. it dont have to be power brakes, just a dual cylinder, though id entertain going power brakes if its possible. if anyone knows anything, or has done this before, id really appreciate it...thank you....


pic below so you can see the type master cylinder currently on the car.

Just so you know, I for one, had no idea you have a 1959 oldsmobile 88..

DOH! Couldn't pass that one up!!

For the rest of your post, I know nothing about brakes on a '59. sorry.

In an all drum systems there would be no proportioning valve. Just two separate distribution blocks one for the front another for the rear, or a single distribution block with two separate circuits and a switch in between to light the brake light to let you know when circuit was leaking. The master would have to be for a drum/drum with the same size pistons in both.

Unfortunately you will have to at least fabricate some adapters and new brake lines to make the front and rear brake circuits separate. There is no direct bolt on for those.

Since I trust my own work, my solution was to replace all the hydraulics in the brake system. I kept the single master, but have all new brake lines, brake hoses, wheel cylinders, master and power booster. When new and tested the system should be reliable for many years without a problem.

X2.
Properly maintained single master brakes are reliable .
The reason dual master brakes were invented was because brake systems weren't being maintained.
Do make sure your parking brake is operable and you have the presence of mind to use it if the hydraulic brakes do fail.

I second that make sure parking brake works if need be. My 57 olds works trouble free with all new brake parts.

Give your drum brakes a chance to work properly if you replace and maintain everything.

I own a 1963 Super 88 holiday coupe in which I had to rebuild the entire drum braking system, and as was said by other responses, single reservoir M.C. work good as long as the shoes are correctly adjusted on all four corners, all the wheel cylinders are good, and no lines are crimped. I had my Delco-Morain M.C. rebuilt and brass sleeved from a company called White Post Restorations, since all the M.C. you can buy look nothing like what I have now, you can tell they are a replacement..

Thank you, well said. White post or karps are the 2 best places to get your brake booster rebuilt.