Headlight motors- how does GM assemble these?
05-09-2013, 12:33 PM
#1
Headlight motors- how does GM assemble these? I was in the process of doing 1 of 2 headlight motor gear swaps last night, and I got over-ambitious in trying to remove the old grease. I pulled up the locking tabs from the metal motor housing to the plastic round gear housing and 2 springs popped out. I knew that was a bad sign that I'd done something I'd regret. I've done a fair number of these and never opened the housing, usually just tightened the tabs.
Inside is the armature/ commutator and a pair of brushes. The brushes are the 2 copper tabs in the pic below. they are held against the commutator by springs that are in the plastic end of the assembly. They put enough pressure against the brushes that you lose clearance to slide the motor shaft past them to secure the 2 halves of the assembly together, and the brush tabs just come out.
I fought with this for an hour before giving up (power went out, took that as a sign to quit trying). If you look in the part of the plastic housing where the plastic gear is, there are 2 small holes above the motor shaft hole for the worm gear. I'm betting GM uses a retainer of some sort to hold the brushes and springs apart while the motor shaft is inserted. I'm thinking about using an old lighter gauge guitar string bent into a U shape through the small holes to hold either side back while I insert the motor shaft/ worm gear and then pull it out, to let the brushes contact the commutator.
2nd pic shows where I think I can pin the brushes back with the guitar string. First attempt with toothpick bits was successful at holding back the brushes, but the 2 problems were: 1) they were too thick to allow the motor shaft and bearing to pass through and 2) how to get them out if I actually got the halves together again.
Anybody ever gotten stuck with this problem? How did you get it back together?
Inside is the armature/ commutator and a pair of brushes. The brushes are the 2 copper tabs in the pic below. they are held against the commutator by springs that are in the plastic end of the assembly. They put enough pressure against the brushes that you lose clearance to slide the motor shaft past them to secure the 2 halves of the assembly together, and the brush tabs just come out.
I fought with this for an hour before giving up (power went out, took that as a sign to quit trying). If you look in the part of the plastic housing where the plastic gear is, there are 2 small holes above the motor shaft hole for the worm gear. I'm betting GM uses a retainer of some sort to hold the brushes and springs apart while the motor shaft is inserted. I'm thinking about using an old lighter gauge guitar string bent into a U shape through the small holes to hold either side back while I insert the motor shaft/ worm gear and then pull it out, to let the brushes contact the commutator.
2nd pic shows where I think I can pin the brushes back with the guitar string. First attempt with toothpick bits was successful at holding back the brushes, but the 2 problems were: 1) they were too thick to allow the motor shaft and bearing to pass through and 2) how to get them out if I actually got the halves together again.
Anybody ever gotten stuck with this problem? How did you get it back together?
05-09-2013, 12:43 PM
#2
TECH Fanatic
I had this problem when I rebuilt my headlight motors on my '87 Formula.
Except those have 4 magnets on them but they are the same concept. If I remember right, I put shaft in so it rested on the magnets and applied a bit of pressure. I took one of my curved picks and pulled back on the magnets one by one till they allowed the shaft to slide through and viola'!! It was a pain in the *** I know that.
Except those have 4 magnets on them but they are the same concept. If I remember right, I put shaft in so it rested on the magnets and applied a bit of pressure. I took one of my curved picks and pulled back on the magnets one by one till they allowed the shaft to slide through and viola'!! It was a pain in the *** I know that.
05-17-2013, 12:06 PM
#3
I used a piece of .010" guitar string. It worked like a charm. Porbably could have used slightly heavier gauge, like .011" or .012"
Carefully slid the 3 piece bearing and commutator shaft past the brushes and got the 2 halves together and pulled the string out.
As little wear as these assemblies get inside from raising and lowering the headlights, I'd advise against ever opening it like I did. But, if you have one that wears out actual motor parts and you can get a rebuild kit and want to do it, it's possible.
Carefully slid the 3 piece bearing and commutator shaft past the brushes and got the 2 halves together and pulled the string out.
As little wear as these assemblies get inside from raising and lowering the headlights, I'd advise against ever opening it like I did. But, if you have one that wears out actual motor parts and you can get a rebuild kit and want to do it, it's possible.