right...it controls the amount of braking when you have weight or no weight in your truck...I have done no mods to this at all...except for that hard line that was cut off that used to go to the top of the diff...other than that I have done nothin...I replaced the brakes, the spring kit in the brakes, the mastercyl..I'm getting good flow when I bleed the brakes, it's just hangin up on something and puts off a loud squeel noise...this the squeel could be from warped rotors..but the shakes...It's hanging up on somethin
