Sunday, 1 May 2016

Automobile Maintenance: Door lock Motor Repair

After décades of continuous operation, these electric door lock motors go bad mainly due to a torn rubber boot. The air gets inside and the grease is lost. Dirt can also accumulate on the slip rings of the dc motor, hindering its smooth operation. First remove the outer cover of the door from inside the vehicle.



Locate the lock motor inside the door.


Amazingly the door lock motor was manufactured by Rockwell International, the famous aerospace company of USA. 





Using a 9 Volts battery, check the functioning of the motor to confirm that it is not working. It also means that vehicle wiring is not the cause.


Now the door motor has to opened (its not working anyway, so go ahead).


After making a cut on the corner shown above, use a flat screwdriver to pry the plastic casing open.


Inside there is a DC motor and a worm gear assembly.


The torn rubber boot was the cause of the fault.


Now apply silicon grease to the worm gear (white colour) and rotate it several times.


The worm gear is pointed to with a screwdriver.


Now apply some penetrating oil (dehumidifier) to the dc motor (especially the sliding contacts of the brushes (commutator).


Here oil is being applied to dc motor.



Now check back the motor with a 9 Volts cell to confirm the repair. Its working. If it works with a 9Volts battery, it would surely work with the 12 Volts battery of the vehicle. Change the polarity of your 9 Volts battery to check for opening and closing.





Now clean the surfaces of the box before applying adhesive.


Using a plastic-special adhesive, close the casing of the motor.


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