I am not an expert, so take
all information and instructions on this page with a pinch of salt. It is
quite possible that they will harm you, your wallet, your car, or all three.
If in any doubt at all, take your car to the professionals. You have been
The pictures/instructions on this page are for a July '98 production date UK RHD 728i; if your car is a different model year, you may find that it is different from what is descibed here. Let me know if you think I should include references to these differences.
With the screws out, lift off the upper part of the
As the next step, detach the faulty solenoid with its housing by pulling it
sideways away from the plastic frame with the connectors. The fork shaped
contacts to the little windings should slide off; in my case I actually had
to apply a fair bit of force.
Lift out the faulty solenoid from its housing:
Once removed from its housing, it was obvious where the solenoid winding
became corroded with the broken wire clearly visible:
Remove the little winding from the contact pin and extend the broken wire by
soldering a short length of similar wire to its end:
Then wind the new wire on the contact pin:
Finally, remove and clean the plungers and seals, then reassemble in reverse order.
I also smeared a little silicone sealant on the mating surfaces to prevent any leaks.
Before fitting the valve in the car, it might be an idea to test it on the bench by applying 12V to pins 1-2 and 1-3, and listening to the clicks of the plungers.
If you find any mistakes or want to suggest additional info
that I should include, please e-mail