Power Window
03-03-2010, 12:11 AM
#1
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Thread Starter
Power Window
It’s been almost a year since I bought my ‘87 928 and in that time I have visited Rennlist several times. I decided to become a member to support this site after I realized how much I have learned from reading what others have written.
I have seen Q&A on power windows but haven’t seen any information on motor brushes. So for my first post , “Power Window Motor and it’s Brushes“.
A dirty armature. The electromagnets can be cleaned with a wire brush but do not touch the wires or the commutator. Clean the commutator with scotch brite.
When cleaning the commutator remove all of the grit between each section. This is from the old brushes and it is conductive.
The brush assembly with one old brush. You will have to cut the wire lead close to the brush so you can remove the old brush and to have enough wire to solder the new brush. Then clean the assembly.
I bought the brushes from Grainger for $10. Part # 1ZRY2. I used a Dremel with a sanding drum to shape them to .248x.248x.375L in. and a cone grinding stone to make a grove for the wire to lay in. Cut the brass conductor off leaving the wire length. Do not use the spring reuse the old spring. Make sure the brush is snug in the holder but slides in and out smoothly. With the wire through the slot of the assembly solder the leads using lots of flux.
Put a small amount of grease on the short end of the armature and slide it into the case. Reassemble the brush assembly onto the commutator. Apply some grease to the worm gear and the end and attach it to the gear box.
I have seen Q&A on power windows but haven’t seen any information on motor brushes. So for my first post , “Power Window Motor and it’s Brushes“.
A dirty armature. The electromagnets can be cleaned with a wire brush but do not touch the wires or the commutator. Clean the commutator with scotch brite.
When cleaning the commutator remove all of the grit between each section. This is from the old brushes and it is conductive.
The brush assembly with one old brush. You will have to cut the wire lead close to the brush so you can remove the old brush and to have enough wire to solder the new brush. Then clean the assembly.
I bought the brushes from Grainger for $10. Part # 1ZRY2. I used a Dremel with a sanding drum to shape them to .248x.248x.375L in. and a cone grinding stone to make a grove for the wire to lay in. Cut the brass conductor off leaving the wire length. Do not use the spring reuse the old spring. Make sure the brush is snug in the holder but slides in and out smoothly. With the wire through the slot of the assembly solder the leads using lots of flux.
Put a small amount of grease on the short end of the armature and slide it into the case. Reassemble the brush assembly onto the commutator. Apply some grease to the worm gear and the end and attach it to the gear box.
03-03-2010, 01:32 AM
#2
Rennlist Member
Nice! Excellent first post. Welcome aboard. I look forward to more tutorials as you work on your car. Please post pics of it.
03-03-2010, 08:59 AM
#4
Rennlist Member
Excellent writeup! Having just done the same I will add one note: the motor is the same for both the 8-tooth gearbox and the 10-tooth gearbox, so if you have to replace just the motor section it can come from any year.
03-03-2010, 09:19 AM
#5
Rennlist Member
Rennlist Site Sponsor
Good post.
Two additions:
- There is a tiny thermal circuit breaker built into the motor. If water gets into the motor, this breaker can corrode and kill the motor. You can sometimes clean it, but may have to bypass it to make the motor work. A simple continuity check will find an open circuit breaker.
- Occasionally, you will find an open circuit in the motor windings - check the connection between the commutator segments and the wires. Scraping a tiny bit of insulation from the wire next to the commutator connection and applying a tiny bit of solder will fix the open circuit. If you want to ensure that it doesn't happen on another segment, and keep the armature better balanced, you can solder every connection.
Two additions:
- There is a tiny thermal circuit breaker built into the motor. If water gets into the motor, this breaker can corrode and kill the motor. You can sometimes clean it, but may have to bypass it to make the motor work. A simple continuity check will find an open circuit breaker.
- Occasionally, you will find an open circuit in the motor windings - check the connection between the commutator segments and the wires. Scraping a tiny bit of insulation from the wire next to the commutator connection and applying a tiny bit of solder will fix the open circuit. If you want to ensure that it doesn't happen on another segment, and keep the armature better balanced, you can solder every connection.
