One of the most common problems with vintage BMW’s is that the plastic gears inside the gauge cluster degrade over time. The delicate plastic gears turn into a soft cheese like material and stop tracking mileage in the odometer. This makes it difficult to tell the true mileage of an old BMW, because often the owner will continue driving the car for years before making a repair.
Fortunately there are several companies now manufacturing new replacement odometer gears, and with a little patience, you can install a new set with a few hours of work. My 1987 325is had a failed odometer due to aged gears, so I created this tutorial video to show you how to install a new set.
Odometer gear installation
1. First, remove the gauge cluster from the dashboard so you can disassemble the cluster on a clean work bench. See my cluster removal DIY here.
2. With the cluster in a clean work space, you’ll need to separate the cluster by removing nine small screws from the back of the unit.
3. Pull the two halves of the cluster apart- this takes some force.
4. Remove the four screws from the rear of the cluster that hold the odometer unit to the board.
5. Remove the entire speedometer unit from the cluster.
6. Remove the screws and small clear plastic window from the speedometer to reveal the odometer gears inside.
7. Carefully remove the old gears and any debris or pieces of gears that fall into the speedometer housing.
8. Follow the DIY video to carefully install the new gears, spacers and bushings into the speedometer.
9. Reassemble the speedometer unit into the gauge cluster board. Install the screws that secure the speedometer to the cluster.
10. Carefully slide the two halves of the cluster back together until they’re flush. Reinstall the nine screws in the back of the cluster that secures the two halves together.
11. Reinstall the cluster back into the car, and test drive to ensure the odometer is working.
View my complete step by step installation DIY video here: