Break lug nuts
Lift Car
Use a Jack Stand!!!!
Take off tire
Remove caliper
Remove disc (may need some persuasion)
Installation is same in reverse
Buy high quality brake parts, and its best to use brand new pads when replacing a rotor.
You will have to open your brake fluid reservoir, and use a clamp to push the piston inward on your caliper in order to re install the caliper. Use brake stop squeak on all contact points between the pads and calipers. Also use brake cleaner on the rotors. Never work on or under a car without the use of jack stand for safety.
You most likely need new breaks and probably rotors
About 30 each for rotors and 2 hours (or less) in labour.
Possible wrong rotors???
The majority of the stopping power is performed by the front rotors. I would start by replacing them.
The front wheels have abs sensors if applicable. The sensors would be mounted to the spindles not the rotors.
probably with his hands.
A 1977 Chevy pickup truck would have rotors in front and drums in the rear
Rotors out of round?
Front Brake Rotors can be a pain, I would recommend going to your local Pepboys, Kragen, O' Reilly's or AutoZone Near you. They will need your year and model of vehicle.
Bad bearings inside or loose castle nut.
I just paid $500.00 to replace all brake pads and the front rotors
Possible that the rear sensors are broken.