When the windshield washer pump in my ’74 Tii succumbed to rust, I improvised an inexpensive and workable replacement using a Datsun 510 windshield washer pump. However, there are numerous Japanese and American washer pumps which would have worked as well.

The procedure is as follows:

1. Disconnect the waterbottle and pump assembly from the car. On later cars, be careful not to pull on it harshly as it might break the end of the reservoir bottle. Disconnect the electrical connections and the fluid connections.
2. Undo the screws at the back of the defunct pump and remove it, leaving only the bracket attached to the reservoir bottle.
3. Purchase a used Datsun 510 washer pump or a new Japanese or American unit. The used route is often cheaper, $5 at the local wrecker as opposed to $11 to $25 for a new unit.
4. Fit the replacement pump to the bracket remaining on the BMW reservoir bottle. Depending on the pump you’ve selected, you might be able to secure it to one of the remaining holes on the BMW pump bracket. Otherwise, a large hose clamp can be used to affix it.
5. Re-install the unit to the car. Remember that the BROWN wire is the ground wire and connect it to the appropriate terminal on the pump. It is usually marked. Also, it may be necessary to trim the white plastic polarized connector housing the wires in the car. Remember, when the connector is installed, the two wire connectors must not touch each other!

The exorbitant price of a new BMW pump at our one and only local BMW dealer (they asked $35 for a new pump) made me resort to this unorthodox solution. The pump works fine, is actually smaller than the BMW unit (with better pressure), and opens up a large variety of pumps at a substantially lower cost per unit should the problem re-occur.

Author: Howard Wong