Rusty Inside Master Cylinder

This is regarding my 1956 Buick manual, single circuit, 4-drum braking system.

I took apart all the brake parts at each corner, cleaned off all the heavy set dirt (there was a lot), installed new rear wheel cylinders, and rebuilt the front ones. I flushed out each line individually to make sure the fluid coming out was steady and clean.

It's pretty rusty and gummed up inside the master cylinder reservoir. I stuffed it with paper towel to let it soak up as much crap as it can overnight. As far as I know, it functions just fine and spits out clear fluid at every corner.

Should I worry about this?

 

Yes ,especially being a single circuit. Why would you not change it too? Brakes are something I wouldn't think anyone would want to compromise on.

 

my 53 had rust in the master cylinder. Sent it off and had it relined and rebuilt. didn't cost much.

 

I don't know if if needs to be changed, but should be pulled and cleaned well....unless it's a high dollar part, geat a replacement, if it is a high dollar part, then pull it, soak it in your favorite rust dissolver, nutrilze, clean well with something like denatured alchol, blow dry and start again.

You question of "should I be worried", is kinda like to old saying "it's only flat on the bottom"

 

He won't be able to reline the resevoir, just the bore.

 

The 56 master is a one year deal if I remember . Rebuild it. Brake fluid loves to soak up water, not too uncommon to see rust in a master.