I recently purchased a '67 Camaro. After driving 2-3 miles the brakes start locking up. It is not from me using them-just driving without using them, they get hot and lock up. After sitting an hour or so they cool and release. I jacked it up and all 4 brakes drums are hot and every wheel is locked up. They are power & drum. Somebody please help!!:(

If no foot on pedal as you drive, then I'd suggest the shoes are adjusted too tight.
Otherwise, if power brakes, then I would look for the booster rod being longer than the depth of the master cylinder causing the brakes to drag.

Welcome to the Club!

How do I check the booster rod? How will I know if it's too long? Thanks so much!

Brake lamp switch to far forward and not allowing the pedal to return to rest??

Regarding the brake lamp switch-how do I check that? Thanks for your help. I already can tell this is going to be a great site. So many helpful people!!!

I'd replace the master cylinder. If all 4 wheels are locking, my guess is that's where the problem is. We had a customer's car do the same thing,and it turned out to be a faulty O-ring in the master, which would swell when hot,and not allow fluid to return, thereby keeping the brakes applied.

As was mentioned,you should check the length of the booster rod to be sure its not too long, but you need to remove the master to check this anyway, so why not do both? A new master is pretty cheap insurance.

Change the master,and be sure to bench bleed it before installation. My 2 cents.

Thanks for all the advice!

I agree with Bob, had this happen and chased my tail for awhile finding the problem. Master cylinder.