SuperPro Rear Spring Shackle Upper Bushing Kit | Universal (SPF2051K)Rear Spring Shackle Upper Bushing Kit by SuperPro These bushings are often overlooked when upgrading the suspension of a 4WD. Leaf spring bushings stabilize the movement of the rear axle, inferior bushes in this area will cause the solid rear axle to move and impart rear end passive steer to the vehicle. It also causes the vehicle to 'wander' all over the road and be unstable under heavy braking. This can be especially noticeable carrying a load or