BMW 31313453521 Front Left Suspension Strut

Struts are marked for right and left installation, and the procedure for front strut, upper strut mount, or spring replacement involves two main steps, The first is to work on the vehicle and carry out removing and replacing of the strut assembly and the second is to dismantle and assemble the various elements on a workbench with the help of special service tools. Start by lifting the car and, dropping the front wheel, dissecting the clip holding the brake fluid hydraulic line to the front strut; unscrew the upper stabilizer bar linking nut while holding the stabilizer bar link ball joint shaft using a slender wrench. Next, unplug the wheel speed sensor wire harness and brake pad wear sensor wire harness from the strut housing, unbolt the front strut pinch bolt and lift with a suitable jack the steering knuckle while pulling it apart from the strut. Maximum range of motion of the CV axle joint should not be exceeded through the steering knuckle, therefore this has to be supported. As an extra precaution in the event that the pinch collar on the steering knuckle gets stuck, BMW special tool 312230 may be required to increase the distance between the two pieces. For installation, position the strut over the alignment pins of the steering knuckle pinch collar and make sure that the areas where the pinch collar and stud clamp are to be assembled are free from oil and grease and locate the position of the strut centreing pin. Therefore, if the strut centering pin is not in place on the upper strut mount, then it is suggested that the positions of the studs be marked on the strut tower so as to be able to set the camber to this position when required. Tighten the spring strut so that is cannot drop out from below and then undo the upper strut mount nuts and carefully get the strut down out of the wheel arch, although the use of a spring compressor will give a little more clearance. The process is a reversal of the removal and involves such details as installation of the bolt head of the pin to the direction of travel, alignment of the steering knuckle with the pins of the strut body, and alignment check on completion.

It is recommended to replace shock absorbers only in pairs, that is, only left or right ones. Take out cargo area trim and lift the vehicle to take off the rear wheels. Place revolve and prevent the falling of the trailing arm by placing an adjustable jack stand from under the trailing arm and then, take off the lower mounting bolt of the shock absorber. Trailing arm should be supported before removing the lower shock absorber bolt as damage to drive axle CV joints may result. Inside the cargo area, unscrew the fastener and get rid of it and likewise, lift the dust cap off. If necessary stabilise the shock absorber by holding it from below and then take out the upper mounting nuts and pull out the shock absorber from the wheel housing. Transfer the mounting plate, dust cover and bump stop and other such parts to the new shock absorber and check for damages and change the worn out components as and when required. The process of installation is virtually the reversal of that of withdrawal and all threaded bolts, nuts, and mated surfaces for the assembly are purged. Place the shock absorber mounting plate on the body with new self-locking nuts: tighten the fasteners only after the car has been lowered and the suspension has settled. Last of all, ensure that the rear drive axle is well positioned in the differential.

Replacing the strut, upper strut mount or spring, calls for the dismantling of the strut assembly out of the car. Start by engaging a spring compressor in a shop vise as shown in figure below for the different spring types to be compressed. Counter lock the strut shaft with a 6 mm Allen wrench and then use a special tool for removing the strut nut. It must not be done using an impact tool. Take off the top struts bearing and other parts that are attached to it. In the event of a new coil spring, there is need to release the pressure on the spring compressor and then get rid of the coil spring. Inspect the strut dust boot, rubber stop, and spring pads and replace those that are worn out. Whenever you are replacing struts, upper strut mounts or springs, then, make certain sprigs are replaced as matching pairs and this you will know from the BMW ID number close to the end. Reassembly is done in the reverse order of disassembly, one has to fit a new upper strut self-locking nut and tighten the nut fully to compress and therefore release the spring compressor. No impact tool must be used to tighten the strut nut. Make sure that the upper and lower spring pads are placed positively on the spring seats before you let off the spring compressor while freeing the spring compressor gradually in order to let the spring to expand. Last of all, take the car to the professional to have it aligned once the work is done.