55 Roadmaster brakes

I have a '55 series 70 Roadmaster with power brakes. I am so unfamiliar with this setup and am looking for a place to start trouble shooting them. My local Buick guy has been unavailable for some time and I can't tap that old noggin of his anymore. Nor is there any one that I know of here that knows about my oldies brakes. That said I also do not want to spend several thousand dollars to repair them either when I have a reasonable mechanical intelligence and lots of time.

It is all original and still has the vacuum system intact. I had the brakes done by a local repair shop several years ago but noticed that there are parts that never got replaced that should of been, ie; the shaft boot at the booster. They worked for a few years then just quit on me and the car has set idle for about three years because the need to earn money took precedent.

I cannot get the brakes bled, either with the car running or turned off. I found that the reservoir cap was not screwed on and empty and could possibly have been that way from the shop that redid them several years ago. I dunno. I used DOT 3 fluid and filled it back up according to the manual, tried to bleed them and nothing. I bought the shop manual and have read the brake section repeatedly.

My next step is to go through the vacuum system to make sure its tight since one side of the booster is vacuumed?

I suspect that the power brake unit may need to be rebuilt?

I welcome any and all suggestions about where to start my trouble shooting of my brake issue. (Wanna get my pup back on the road before winter, if possible.)

Thanks!

Chuck

Hi Chuck,

I recommend to first bleed the master cylinder, there are a lot of videos about bench bleeding on youtube, or you first try this method without bench bleeding:

https://www.youtube.com/watch?v=oi4BnNA3Ep4

You should bleed without the engine running. The vacuum system is NOT useful for bleeding. It's quite a long way to bleed a system that has been empty for such a long time. After having bled the master cylinder I would try this one:

https://www.youtube.com/watch?v=U_7bPdeh_jM

because here you can "fill" the whole system in one step and watch at which wheel the fluid comes out. When you have done this and the brake pedal is firm you can switch to the vacuum system and see if anything is wrong with that.

Cheers
Michael