How do i install a power booster for a 1992 GMC Sierra, 2 wheel drive?

Here's a link on your brake booster, Repair Guides Brake Operating System Vacuum Booster AutoZone com

If you let go of steering wheel and step on brakes does the wheel vibrate?

I'd say its either warped rotors, power steering malfunction, or possible wheel bearing, although if wheel bearing you should feel/hear a hum which would get louder depending on which way you turn the vehicle.

Sounds like the electrical actuator is bad on the front axle.

CHECK VACUM LINE & GASKET ON BOOSTER. IF YOU PULL IT OUT & HEAR AIR ESCAPING THE BOOSTER IS WORKING.

Did you bench bleed your master cylinder before you installed it? If not you may not be able to purge the air from it.

George

The first thing to check is the brake lines, this lines rot and leak fluid, most times its the line going to rear wheels that runs along side of fuel tank along the frame,

check wheel bearing... and make sure that the metal shims are installed with the pads. they prevent noises

go to a wrecking yard

i have ran into this problem , but on earlier gm products---check the local dealership or a well known mechanic shop that has all data and check for bullitains. what i had found out was there was some trucks that gm had installed the wrong power booster . not saying your booster is to blame, but may be a great place to look seeing you replaced abs modules ,master cylinder ect---hope that helped out!!

You need to have the computer scanned for trouble codes before you waste any more money.Good Luck.