Technical 1950 Pontiac Brake Issue

Hey there everyone!

Strange issue with the brakes on my 1950 Pontiac 2 door Streamliner. Seemed like I had a hanging drum on the driver's side rear because it ended up getting hot and even smoking a bit on a drive this past fall. The brake lights were stuck on and the pedal was rock solid due to the excess pressure. I got under it and ended up replacing the flexible rubber brake line at the rear axle as well as the entire hard line running from the master back, bled the system and seemed like it was good to go. The existing rubber line had swollen so badly the fluid had a pinhole diameter to move through.

I haven't driven it much since it's been colder than hell, but I take it out every once in a while and also let it run once a week or so. The brake problem seemed to have been solved with replacing those lines and bleeding the system. I let it get nice and hot this past weekend while I was working on some other projects in the garage and noticed my brake lights were on. They had not been on when I started it and the brake pedal had a normal feel to it. I got in the car and the pressure was back in the pedal, yet the car hadn't moved an inch.

The master cylinder is located on the driver's side frame rail, the exhaust is on the p***enger's side, so I can't imagine it is the master getting hot. Also, the brakes were ice cold obviously since it was freezing out and the car had never moved. The pressure in the system had simply increased by the car idling in the garage.

Any ideas on where to start with this? Warmer weather is coming and I'm excited to get her back on the road.

Thanks in advance!
Chris

 

Pushrod into the master needs to be adjusted ... back it off til you have 1/4" - 3/8'' play on the pedal ...
And, if you can see into top of master, make sure the tiny byp*** port is open. A tag wire will do the job.

 

You’re a gentleman and scholar

 

Guess I never suspected that being an issue when the car is just idled and not driven.

 

And there's damn few of us left ....

 

Just wanted to follow up and let you know you were 100% right. Adjusted the pushrod and it's good to go. Thank you again!

 

I learned this when I was doing brakes for a living, the lesson stuck with me. I still recall the car, a 1966 Impala, maroon 2 door HT.