My brakes have gotten progressivly worse, so bad I won't even drive it for now. The brake pads and shoes are new and I have bled the brakes, no air found. This leads me to believe my power booster needs replacing. I did a search on this subject and found posts for 1st gen K5's where people replaced with 3/4 ton boosters and now they can stop on a dime. So my question is what upgraded booster will bolt right into the 73?