So two things? I've had 2 things just start happening the last few weeks... at basically the same time...

First:
I noticed recently when I would drive the Camaro it would start feeling like it was braking after 10 minutes of driving so I brought it home Put it up on the lift and you could smell the brakes... As if I was riding the brakes... and the wheels would not turn with the car in Neutral... but if I wait 15 minutes and car cools down the wheels turn free again? I have not encountered before this happening with my rear brakes. I pulled the Wheels and Drums and everything looks great and you can tell its all been redone recently.

Second:
I believe I'm having Heat soak or Vapor Lock? kinda weird because I have not had this issue with this Engine Carb setup for everal months of driving... but oddly enogh the last 5 or 6 times I have taken it out I get somewhere and if it sits for 20 minutes, Get it in and it bogs and runs like a turd and I have to hold it to floor to get it to come out of it... I limp it home and it sits and cools and is fine again... I've heard put the carb Spacer on will help but I tried a 1/2 inch and I don't have the hood clearance... not sure a 1/4 is worth trying?

These things started about the same time, not sure if they could be related?

Any Thoughts??? Thanks,

Michael

 

First:
You might ensure rear brake line is outside frame rail(s).
Might try a temporary heat shield about master cylinder and the brake plumbing in engine compartment.


Second:
Try the 1/4 inch, can't hurt.
Old school trick is loosely wrap gas line with alum foil so the foil acts as a heat deflector and radiator.
Another trick is adding the spring loaded clothes pins about every couple inches onto the fuel line serving as radiators.

 

If headers installed, they create lots of heat, moreso than cast iron manifolds.
You might have to set up a cooling fan in front of radiator with a 5-10 minute shut-off relay.

 

I had the exact same brake problem as you many years ago with my first 69. Believe it or not, it was due to having air in the brake line. I'd adjust the pedal rod to where the brakes grabbed fine. But the adjustment was very touchy, crank the rod in a hair and the pedal would go to the floor. After driving a short bit, and as the brakes heated up, they would start to lock up and the pedal was stiff as a brick. Let it set and cool off for a while, and the brakes were loose again. It was driving me nuts chasing the adjustment back and forth, but yep, bleeding the brakes took care of it.

 

Thanks for the ideas! Ill try bleeding the brakes! and looking at lines vs exhaust...

 

Brake fluid will adsorb water over time. Flushing the system may help, Did you do the recommended brake adjustment?

Mechanically over heating a drum brake should not cause it to tighten since the drum should be expanding. A very common cause for this is a bad flexible hose going to the rear axle. The hose breaks apart inside and your high pressure brake fluid forces thought it but then it can not escapes back so and it holds the brakes on until is slowly bleeds down.