how to physically check your brake pads and drums?

Most brakes new are .5" (half inch) new. Get a small screwdriver one with a quarter inch wide blade. Carry it with you when you do your pretrip. You can rest the tip near the brake lining to gauge how much lining you have left.

 

Pads are for disc brakes, shoes are for drum brakes.

 

If you have no brakes get a job hauling bulls they never stop!

 

9/16"????? well it looks like we have a disagreement. This is what the DOT says: https://www.fmcsa.dot.gov/regulations/title49/section/393.47

 

You'll want to look at the drums and check them for rust. Of course they will be rusty if they were wet when the truck was parked but if only one has rust you know something is wrong.

 

If only one has rust, the other three are new.

 

Get out the ol' trusty tape measure. All your shoes should be a 1/4" NO LESS. NO cracks HALF of the friction distance/area. Drums should have NO cracks at all. Good time to check slack adjusters as well.

 

but brake shoe's have brake pads aka lining, a shoe with out a pad is well, worthless unless pads of asbestos are on it.

 

while you're under may as well check everything else.