Technical '41 Chev. brake pedal not returning

The '41 Chevy sedan I bought last month has power 4 wheel disc brakes on it with the booster and master cylinder mounted under the floor in the stock location. When the car is first started and for ten minutes or so afterward, the brakes function and the pedal returns just like it should but then it begins to fail to return. A little at a time but within a few miles I have to hook my toe under the pedal and pull it up to release the brakes. The brakes work entirely normally except for that issue.
Anybody got experience with this problem or something similar?

 

The original set up used a return spring.

 

There is supposed to be a return spring on the pedal. This is on a 50 but it should be pretty close to the same in that if you still have the stock pedal it should have a hole for the spring to hook into and pull it back. Without the spring the pedal's weight pushes on the piston all the time.

 

This will solve your problems

 

Have same problem.

 

The return spring is present and hooked up; it doesn't explain the 'works properly for awhile before problem slowly coming on' part of the problem.
Could the booster somehow be the cause? I'm not familiar with the inner workings of the booster so I don't know if that is feasible.
I've been scouring the internet looking for an answer and haven't come up with anything.

 

Is that a kit or a solution that you made up? If a kit, could you point me toward where you got it?

 

I did find this thread and got a couple of possible answers; I'll look into the booster adjustment described in it.

https://www.jalopyjournal.com/forum/threads/brake-pedal-wont-return.714825/

The fact that I already have a return spring (that has plenty of tension) kind of throws that out of the window as a source of the problem by my way of thinking so I'm still looking.

 

My problem was the booster was getting hot and making the rubber diaphragm more pliable so to speak, letting the engine vacuum apply the brakes when warmed up.
I added a little extra clearance between the booster pin to master piston and solved the problem.
You must also have a good return spring on the pedal.

 

How close is the master and booster to the exhaust under the car? Sounds like things might be heating up and creating issues.

 

I had a similar problem. I disconnected the booster and it would work fine. Reconnect it and the pedal wouldn't return. Changed the booster and it works great. Try plugging the booster vacuum line to see if it's the booster.

 

It's on online kit I came across

 

I'm saving that photo. Someone is always asking that question on the net.
As far as the original question, if you do have a return spring hooked up and it is hooked up right I'd check to make sure that the pedal wasn't hanging up on the floor board, insulation or carpet I've had to fine tune the brake and clutch pedal placement on my 48 more than once and I think that the setup is close to the same with the pedal shaft bolting to the arm.

 

I sure appreciate all the input, I'll finally get a chance to get under the car and start working my way thru the tests and things to check that have been suggested, I'll post updates as soon as I can.
Thanks folks!

 

Is this an aussie company?

 

Not Ozzie but a US business that I stumbled onto