I recently overhauled the brake system on my 74 K20. New rotors,calipers, pads, wheel cylinders,master cylinder and booster. i went for a test ride and noticed when i push in the brake pedal when coming to a stop the front of my truck starts shaking and shuddering pretty bad. the pedal pulsates also.... one thing i notcied when i bought the new master cylinder was they gave my a rounded style one instead of the more square style one that was on it. When installing it i noticed i had to swap where the brake lines go into the master cylinder. On the square style one that i originally had on it, the bigger brake line when to the port that was farthest back on the master cylinder. and the smaller one to the front. On the new rounded style one they gave me The bigger brake line goes to the front port and the smaller one to the rear. After a little research i found out that the square style one is for 1/2 tons and the rounded style one is for 3/4 tons...could this have anything to do with the shaking and shuddering or would it not make a difference? the square style one worked fine for the 2 years i drove it before changing it so maybe ill buy another one of those...