The front suspension shock absorbers on E53 cars are MacPherson struts, which are a major component of the front suspension and support the spring. Most strut assembly components are available as replacement parts, and it is important to always replace struts and springs in pairs. The process of removing and installing the front strut assembly involves raising the car, removing the front wheel, detaching various components such as the brake fluid hydraulic line and wheel speed sensor wire harness, and removing the upper stabilizer bar connecting link mounting nut. The
Steering Knuckle is supported with a suitable jack, and the fasteners securing the front strut to the steering knuckle are removed. In the engine compartment, the position of the strut centering pin or support bearing studs on the strut tower should be noted or marked. The spring strut is secured against falling out, and the upper strut support bearing fasteners are removed. The strut is then removed downwards out of the wheel arch. If the strut is being replaced, it should be disassembled and reassembled on a workbench. When reassembling the strut assembly, it is important to use new nuts and bolts, counterhold the stabilizer link ball joint while tightening the nut, and have the car professionally aligned if installing a strut without a centering pin. Replacing the strut, upper strut mount, or spring requires removing the strut assembly from the car and disassembling it. A spring compressor is used to compress the coil spring, and a special tool is used to remove the strut nut while counterholding the strut shaft. The upper strut bearing and related components are removed, and if a new coil spring is being installed, tension on the spring compressor is relieved and the coil spring is removed. The strut dust boot, rubber stop, and spring pads should be checked and replaced if necessary. The strut, upper strut mount, or spring is then replaced as needed. It is important to replace springs in matched pairs and use a new upper strut self-locking nut. The assembly process is the reverse of the disassembly, with attention to correctly installing the upper and lower spring pads before releasing the spring compressor. The spring compressor should be released carefully and evenly, allowing the spring to expand slowly. Finally, the car should be professionally aligned.