The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 1966 Brake Master Cyclinder Leak

So I’ve got brake fluid leaking out of the back of the brake master cylinder. Also now that the brake fluid is low I can see some rust in the bottom of the reservoir.

Mine is power brakes with the flatter vac booster a single diaphragm I think. And one brake line off the master cyc. 4 wheel drum.

So I’ll need a new master cylinder.
Should I replace the brake booster at the same time? Could the fluid have got back into the booster and caused damage?

Would it be an upgrade to go with a master cylinder that has two exit ports and do some plumbing to separate front and rear drums? It’s always made me kind of nervous that the whole show is running off one shared line.

Looks like Rock Auto has a 1 inch master cylinder with booster for a 1967 c2500 with two outlets. I think that might work.

But I'm glad i don't have any fresh paint on my fenderwells now :)

Yes the dual reservoir M/C would be an upgrade. 66 was the last year of the single system. I believe along with the master cylinder you would need the proportional valve block.

This setup will work for you :

brake booster and MC mounted in engine bay

There are other photos of my engine compartment on the site there if you want to see some other angles.

-W

p.s. this is a text write up of how the brake lines on my truck were routed, it may have no bearing on your set up :

brake line routing

" It’s always made me kind of nervous that the whole show is running off one shared line" that truck has lived it's life for 50 years with that setup. it worked fine for what it was designed for at it's and how vehicles were driven. It depends on what you want to do with the truck and how you are going to frive. if you are going to uprade the power and drive it in todays hurry up offensive style in heavy traffic then I would make sure to upgrade the system.
ron

Thanks Woogeroo! your pics confirmed what I was hoping.

This is the setup I'm going for. I ordered a loaded booster / master cylinder for a 1967 2500 from Rockauto today. it's the same listing as a 1969. Classic Industries has a proportioning valve for drum/drum I'll get.

I'm planing to replace the old lines with stainless tube while I'm working on it. Maybe even braided hoses if I come across some at a good price. I know I don't need them for this application but I think they look cool.

one question... does the smaller brake line run to the front or rear brakes on your truck? (the one forward after the valve, I think it looks smaller at least) I think the proportioning valve I'm looking at getting has a port for each front brake and one to split at the rear axle. but I'm not sure yet.

Thanks, Zach