Automatic seat belt motor repair

[Doctor J]

This instruction can also help to those who would like to repair power window motors.
Instead of purchasing complete motor, the armature or brush holder [the parts that go bad]can be bought for lot less at self-service yard. I did this for my own Camry; the parts were bought during the swine flu scare so the cashier did not charge me too much
I would like this thread to be "stickied". Thanks for reading.
Automatic seatbelt motor overhaul:
The motor needed to be removed and repaired if it makes loud whine [“electric drill”] noise or is not running at battery voltage ignition on, engine is not running; it may start to work after engine starts. The motor is permanent magnet constant torque DC motor with worm gear, carbon brushes and ball bearing #608 at the thumbwheel end of the shaft
To check:

• Get access to the motor:
  • Remove rocker panels;
  • Push front seat forward to the end of its travel
  • Remove B-pillar lower trim piece; do it when outside temperature above 70 degrees F,
  • Disengage lap belt from trim piece

• At the motor:
  • Remove 2 larger Phillips screws connecting belt tape guide to the motor housing and 2 screws [10 mm hex head] attaching track to the pillar
  • Remove 3 small screws at the gear cover
  • Remove tape guide and gear cover [do not lose small thrust washer under it] pull the tape away from the plastic gear; temporary re-install the gear cover on 2 screws
  • Unplug power wires to the motor, then using suitable adapter apply power to the motor from cigarette lighter socket; use 10 Amp fuse in the adapter

• If motor runs with noise [no load] and heats up, remove motor
  • Detach electrical connector from the pillar mounting hole
  • Remove 3 motor mounting screws [10 mm socket]
• Overhaul the motor:
  • Break loose two Phillips screws attaching the motor housing to the gear housing;
  • Pry thumbwheel from motor shaft end;
  • Hold exposed gear teeth [right] with your finger to prevent pulling of the rotor by magnets in the housing; remove screws completely then pull the motor housing off, save spacers from inside
  • Slowly pull the rotor end from the gearbox; DO NOT LOSE 2 mm Thrust Ball at the end of the worm shaft;
  • If rotor has discolored dark windings and bluish tint on steel parts the rotor has shorts and needs to be replaced
  • If bearing is frozen, worn or noisy replace it
  • Clean carbon from brushes; pull the brushes out of holders, save the springs
  • If brushes are shorter then 5 mm replace them by re-soldering the braided ends
  • If reusing the rotor, clean the commutator using green scotch bright pad.
  • Remove gear cover and plastic gear

• To assemble:
  • Install housing with lettering at same side as gear cover; only the armatures rotors] are interchangeable from left to right;
  • Wrap the leads of to the brushes around the tabs to hold them in holders during the installation of the rotor;
  • Using dab of grease install thrust ball; hold rotor with ball end facing up;
  • Lower the gearbox on the rotor; install the gear; temporary install the gear cover;
  • Release leads from tabs -- this will bring brushes back to the commutator.
  • Again, when installing the motor housing hold exposed gear teeth with your finger to prevent pulling of the rotor by magnets in the housing. Don’t forget to install spacers on the beading using dub of grease prior to assembly!!

• Test the motor, and then install it in the car.

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Good rotor and bad “blue” rotor [on the left] The 2mm thrust ball goes into the “worm” end; thumb wheel goes on the hex end after assembly; when pulling the motor housing, hold exposed gear teeth [right] with your finger to prevent pulling of the rotor by magnets in the housing.
http://farm4.static.flickr.com/3402/3549377273_10f7be3e96.jpg
Motor housing with magnet and gear cover are removed; note burned armature rotor
http://farm3.static.flickr.com/2484/3549377597_1bdc727918.jpg
Gear removed; rotor is ready to pull
http://farm4.static.flickr.com/3621/3549378567_8f03b7bb55.jpg
Bad rotor armature; spacers on the right
http://farm4.static.flickr.com/3305/3549378005_fd6070423b.jpg
Plastic gear; large teeth are moving the tape hooked up to the belt
http://farm3.static.flickr.com/2448/3549376991_4bf6af55c7.jpg
Install housing with lettering at same side as gear cover; only the armatures rotors] are interchangeable from left to right.
http://farm4.static.flickr.com/3615/3556784778_4c7f0a3a41.jpg
Wrap the leads of to the brushes around the tabs to hold them in holders during the installation of the rotor; using dab of grease install thrust ball; hold rotor with ball end facing up; lower the gearbox on the rotor; install the gear; temporary install the gear cover; release leads from tabs -- this will bring brushes back to the commutator. Again, when installing the motor housing hold exposed gear teeth with your finger to prevent pulling of the rotor by magnets in the housing. Don’t forget to install spacers on the beading using dub of grease prior to assembly!!