To inspect slack adjusters on S-cam brakes, you need to:

Question

Check each slack adjuster after parking on level ground, setting wheel chocks, and disengaging the parking brake. Pull the slack adjusters to make sure they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

Accepted Answer

Chock the wheels and disengage the parking brake.

Answer

Park on a hill and test the brakes.

Answer

Put on gloves and push in the slack adjusters.

Answer

Remove the drum and look inside.