Project E36 M3 - Replacing Rear Side Window Trim and Gasket June 28 2020

The rubber trim around our rear side windows was starting to crumble from age, so it was time to replace it. We bought some new genuine BMW rubber trim bits and got to work. Some of the parts catalogs don't have clear diagrams of the parts, so we've listed them for clarity. For our coupe, we bought the following parts: 

Lower window trim, left: 51369119963

Lower window trim, right: 51368119964

Window moulding, left: 51368119961

Window moulding, right: 51368119962

Sedans, convertibles and wagons will use different part numbers.

We start inside the car by removing the trim piece circled above. Pull up on it to release it. Next, push up on the tab that is on the underside of the adjustment button and pull the adjustment button inboard to remove it.

Remove the nut circled above, and remove the seat belt. 

Remove the trim piece covering the B-pillar. Shown above is the outboard side of the trim piece. Note the hook that holds it in place. Pull up on the trim piece to free it. 

Remove the two T-40 Torx bolts that secure the seat belt mounting bracket. Be extra careful not to drop the bolts down into the B-pillar. Slide the mount down and then rotate the mount as shown to free it.

Turn your attention to the rear of the window and remove the screw circled above. This is a T-20 Torx fastener. There are a few items in the fastener stack up. Keep track of the order and orientation of these items.

Tape the window in place from the outside so that it doesn't fall out and shatter when you remove the last nuts holding it in place. An alternative is to have an assistant help you hold the window in place.

We're ready to take out the last two nuts and free the window. On the inboard side of the B-pillar, there are two 10mm nuts holding the glass in place. Remove them and be very careful not to let them drop into the B-pillar. Only the bottom nut is shown circled above, but the upper nut looks the same as the lower nut.

Remove the window and set it aside. You can see the two studs that the nuts attach to.

Remove the inner felt-lined rubber trim piece. It simply pulls off the window frame with no fasteners or clips holding it on.

Ewww. Look how old and crusty our window moulding is.

Remove the window moulding as shown. It should pull out without too much resistance. Before we get to the next step, we recommend laying out a drop cloth on the floor. There will be chunks of old rubber and gooey adhesive that will make a mess.

Remove the lower trim piece. It is simply a plastic piece that is held in place with double-sided adhesive tape. We used a nylon trim removal tool to pry up on it without damaging the paint underneath.

The adhesive-backed foam didn't want to come off easily on its own. We tried putting Goo-Gone on the adhesive backed foam and scraping at it, but that didn't work very well. The Goo-Gone needed more time to penetrate and dissolve the adhesive. We cut strips of paper towel, soaked them in Goo-Gone and covered it in plastic wrap to slow the evaporation of the solvents. We left it for several hours for the Goo-Gone to do its work. We then scraped off the foam with our nylon pry tool. We repeated this process three times to get everything off. Here is a link to the exact product we used: Goo-Gone*

This is how everything should look like with all the gaskets, trim pieces and adhesive tape removed. Make sure you clean off all the Goo-Gone thoroughly, as you don't want any residual Goo-Gone attacking your new adhesive.

Reinstall the window moulding as shown. Without exposing the adhesive backed tape, test-fit the lower trim piece. It should look like the photo above.

Reinstall the felt-lined window gasket around the perimeter of the window, and then place the lower trim piece in place. The lower trim piece should touch the window gasket. Lay down a strip of painter's tape or masking tape along the edge of the lower trim piece. This will help you to line up the trim piece accurately during the final installation.

Expose a small section of the adhesive backed tape and carefully place the rear of the lower trim piece in position. You'll likely only have one shot at this. Once the adhesive sticks, it will be very hard to remove it. With the lower trim piece placed accurately, begin to remove the adhesive tape backing and press the lower trim piece into position.

The corner is a little tricky in how all the pieces overlap each other. This is how everything should look in the final configuration. With all your new trim pieces back in, you can reinstall your window. Note that the rear screw is nearly impossible to reinstall without an assistant holding the plastic nut on the outside while the screw is turned from the inside. Also, be sure not to over-tighten the front window nuts. You can crack the glass if you apply too much torque to the nuts. Just snug them down and don't overdo it.

Congratulations! If you've finished, step back and admire your window trim that is crack-free and weatherproof. It's the little details that can make a big difference in how your car looks.

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