A unique feature of the Whiteline suspension system for the Mustang is the use of a Watts linkage for the lateral location of the rear axle. For cars that have a 3 link rear suspension an additional linkage must be added to keep the axle from moving from side to side. The most common way to do this is a Panhard rod which is simply a lateral arm attached to the axle and chassis. The Panhard rod is effective and simple but has a drawback. As it swings through its arc, it causes the rear axle to move back and forth from side to side. This can cause some side scrub and a twitchy feeling at the rear of the car. The stock suspension uses a somewhat short Panhard rod. The shorter the rod, the worse the side to side motion will be. The Watts linkage uses two shorter lateral arms that attach to the axle via a rocker arm. As the axle goes up and down and articulates the rocker makes up for the difference in arcs between the two links ensuring that the axle will maintain a vertical path. The rear suspension roll center is determined by the height of the rocker pivot and the Whiteline Watts linkage lowers the rear roll center over stock by having the pivot below the rear axle centerline which will help the car get more off the corner bite. The kit is a marvellously complicated piece which even requires a new diff cover, but it does its job technically better than simply changing the Pahanrd rod for one with stiffer bushings or moving it on its mounts for a lower roll center (part number KDT916).
To make room for the Whiteline Watts linkage, the stock rear swaybar must be removed. The Whiteline rear bar is designed to work with the Watts linkage and is thicker and 4-way adjustable to boot. The Whiteline bar has new axle mounts with urethane bushings and heavy duty billet aluminum, ball and socket joint endlinks that are adjustable so that all preload can be removed from the system (part number BFR65Z).
The matching front Whiteline sway bar is also much bigger in diameter with 4-way adjustability. It also has urethane bushings and strong billet end links. Billet aluminum clamps keep the bar from walking back and forth as well (part number BFF55Z).
To install the suspension, first remove all the stock stuff. The third link requires removal of the rear seat to access the mounting bolts.
The Whiteline rear bar is totally different in size, width and mounting configuration so comparing it to stock isn’t very useful. We did the usual teflon tape where the bushing ride trick before installing it.
You can see how much beefier the Whiteline end links are compared to the stock Ford ones. The Whiteline links are also length adjustable so if you cornerweight your car you can get rid of all the bar preload after the cornerweights are set.