HomeBMW E31BMW E31 Sunroof Repair - 1990-1999 8 Series - Trolley and Gate

BMW E31 Sunroof Repair – 1990-1999 8 Series – Trolley and Gate

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Repair Summary
This article gives detailed instructions on repairing the internal sunroof components in a BMW 8 series E31 vehicle. Even though we used a 1995 840ci to perform this repair, this article can be applied to any 1990-1999 8 series vehicle with minor modifications to the repair steps.
E31 8 Series 850CSi
E31 8 Series 850Ci
E31 8 Series 840i
E31 8 Series 840Ci

A BMW E31 sunroof repair requires removing and replacing the internal plastic parts.

One of the major "Achilles heels" of 1990-1999 8 series coupes is the complicated sunroof mechanism that slides and lifts the sunroof panel on the roof of the vehicle. Years of heat and wear and tear cause the plastic parts inside the sunroof frame to crack and eventually fail, often leaving frustrated owners with a partially open roof. The good news is parts for 8 series sunroofs are readily available and can be installed without taking the car to an expensive repair shop or dealership.
Sunroof frame from our 1995 840ci
Although not required, it is highly recommended that the entire sunroof frame is removed from the vehicle. The reason why is it is difficult to clean out broken plastic parts and properly lubricate the trolley tracks with the sunroof frame still installed in the roof of the vehicle. Removing the sunroof frame from the vehicle requires removing the headliner and is not covered in this article.
Although there can be extensive damage to your sunroof including a broken slipstream deflector and rain gutter, the main components that will need to be replaced are the guide (also known as the "trolley") and the gate. Due to the lack of information online concerning replacing the trolley and gate in 8 series' sunroofs, we are focusing this article on rebuilding these two parts.
Below we give step-by-step instructions on replacing the trolley and gate in your E31 sunroof, along with a required parts list and a video of the repair.
If the video does not appear below, please click here to view
View the video version of this repair.
View the detailed parts diagram for this repair.
Includes detailed part diagrams, part numbers and links to purchase all of the required components needed to complete this repair.
Before starting this repair, you must have the following required parts.
All BMW E31 8 Series vehicles
One of the first parts to break in your 8 series sunroof, the sunroof guide (also known as the trolley) slides the sunroof panel forward and backward along the track. Always replace both the left and right trolleys when repairing your sunroof.
All BMW E31 8 Series vehicles
One of the first parts to break in your 8 series sunroof, the sunroof guide (also known as the trolley) slides the sunroof panel forward and backward along the track. Always replace both the left and right trolleys when repairing your sunroof.
All BMW E31 8 Series vehicles
One of the first parts to break in your 8 series sunroof, the sunroof gate lifts the sunroof panel when it is put in the vent position. Always replace both the left and right gates when repairing your sunroof.
All BMW E31 8 Series vehicles
One of the first parts to break in your 8 series sunroof, the sunroof gate lifts the sunroof panel when it is put in the vent position. Always replace both the left and right gates when repairing your sunroof.
Repair Steps
Section 1 - Replacing the BMW E31 sunroof internal parts
As previously discussed, although not necessary, we highly recommend removing the sunroof frame from the vehicle before starting this repair. Removing the frame allows you to properly extract all of the broken plastic pieces from the assembly and to properly lubricate the tracks. Even the smallest piece of broken plastic can jam the assembly causing it to break.
  1. Before starting the repair, remove the sunroof motor from the front of the frame. It is held in place with two T25 torx bolts. The motor must be removed in order to remove the trolleys from their tracks.bmw e31 sunroof repair - remove the sunroof motor from the frame
  2. Remove the front slide rail from the sunroof tracks. it is held in place with four torx screws. bmw e31 sunroof repair - remove the front track rail from the frame. It is held in place with 4 torx screwsRemove the front track rail
  3. Grasp the trolley and slide it forward, then remove it from the frame. Pull the trolley's cable out of the copper tubing that leads to the motor.bmw e31 sunroof repair - slide the trolley forward and remove from the frameextract the cable from the copper tube that leads to the motor
  4. Repeat the above steps on the other trolley.
  5. Thoroughly lubricate the tracks and the new trolley cables with marine-grade grease.bmw e31 sunroof repair - Use marine grade grease to lubricate the tracks and cables bmw e31 sunroof repair - lubricate the sunroof tracks bmw e31 sunroof repair - lubricate the cables
  6. Install a new gate onto the side of the trolley by pressing the pin on the side of the trolley into the track on the side of the gate until it snaps in place.bmw e31 sunroof repair - the sunroof gate bmw e31 sunroof repair - Locate the track on the side of the gate locate the trolley pin  bmw e31 sunroof repair - Press the trolley pin into gate track until it snaps into placeThe complete assembly
  7. Install the new trolley cable back into the copper tube, then slide the new trolley/gate assembly back on the track. Replace the slide rail securing it with the four torx screws. Slide the trolley all the way to the back of the frame.bmw e31 sunroof repair - insert the trolley back into the rail and slide it to the rear of the frame
  8. Repeat the above steps on the opposite side of the frame.
  9. Attach the arms of the rain gutter to the plastic mounts on the rear of the gates.bmw e31 sunroof repair - attach the rain gutter arms to the rear of the gates
  10. Reinstall the sunroof motor. Use a 4mm hex bit to tighten the mounting bolts.
  11. Test the trolleys by manually turning the motor with a 4mm hex bit clockwise. They should slide effortlessly down the tracks. When they get to the front of the frame the gate should lift up as shown below.bmw e31 sunroof repair - manually turn motor clockwise until trolleys reach front of frame bmw e31 sunroof repair - gates in raised position
  12. Reinstall the sunroof frame back into the vehicle.
BMW E31 Sunroof Repair Finished

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