Rear diffuser installation (e36 / e46)

Approximate installation time: 1 hour.

Tools needed: Drill, 6mm drill bit or larger, 10mm socket or open-end wrench.

Installation difficulty: Easy (basic mechanical knowledge)

The first thing you should do is identify all the hardware to proceed with the installation.

Each of the pieces of the diffuser is attached using the shortest screws in the kit. Each bolt has 2 washers and a lock nut.

The medium-sized screws are the ones you should use to install the diffuser to your bumper. In other words, these are the ones that screw the diffuser to the bumper itself, so it is also important that you use 2 washers (one on each side) together with its corresponding brake nut.

The two longest screws are the ones that hold the diffuser to the spare wheel well and, like the rest, they have 2 washers and their brake nut.

In some cases (depending on the extras on the car), the spare wheel well may be completely flat or have some other shape. In any of these cases, the diffuser can be installed, but it is important that you use the spacer caps sent in the kit if your wheel well is different from the rest. The bushings are included in any of the cases and would be positioned between the bumper and the main plate of the diffuser at the points marked below:

As for assembly advice, each master has his booklet, and this is how we proceed:

1.- Assemble the diffuser as a whole, using the shortest screws with their corresponding washers and nuts to join the pieces together.

2.- Position it and center it with the bumper, mark the points where you will screw the diffuser to the bumper and to the spare wheel well.

3.- For greater ease, you can remove the bumper, since this way it will be easier for you to install the screws that join the diffuser and bumper as you have better access to the nuts. If you do not want to remove the bumper, it is not necessary, but it will be more difficult (but not impossible) to access the nuts.

4.- Use the medium screws to join the diffuser and bumper and install the spacer bushings if you see it necessary. These bushings are only for the central plate, as indicated in the previous image.

5.- Check everything and return the bumper with the diffuser mounted to the car (if you have removed it for installation). Tighten the bolts that secure it to the spare wheel well and you're done.

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