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How to save a rear window motor

SurfinCR

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i apologize if anyone has covered this before i did a search and couldnt find anything. on both the 84 and 86 blazer i have the window motors died and rather than sinking money into a new one i wanted to find out why they died and if they could be repaired. Turns out they are incredibly simple and there really should be no reason for a replacement. on both the cause of death was the rear window seal leaking and moisture getting into the motors causing the rust to arc out the motor.

here's the steps i took to succesfully repair both (pictures will be provided tonight.)

1. remove the two bolts.
2. lightly tap the cover that attachs to the cable and remove
3. on the plate that contains the brushes there are two clips on ether side holding it in place. (best trick i found to remove them is use one screwdriver to push down on the middle of the clip and a second to pull the top of the tab out as it comes up. ) Also note the brush springs do not need to be removed
4. Once both tabs are released the brushes will slide out,make sure to remove completely as one is attached to the outside case DO NOT PULL OFF.
5. after both brushes are out the board can be moved out of the way.
6. pull the stator out
7. on the stator clean the communtator (copper end) using emory cloth to remove the bulk of the discoloration. Dont go nuts cleaning you only want to remove a small amount.
8. this optional but i find it has great results. use a wire wheel to do a final cleaning of the communtator
9. Use a razor/compressed air to clean out the gaps in the communtator
10. use a wire wheel or sand paper to remove any rust on the metal of the stator
11. for the next step you can remove the other cover if it makes it easier or it can be left. (to remove the cover use a knife to cut the rubber from the plastic connector to the metal plate. tap the cover to seperate from the metal body then slide the cover from under the connector. do not force!)
12. clean any rust on the inside of the metal cover
13. clean the metal plates attached to the coil (i use emory cloth as well as steel wool)
14. Assembly time, if you took off the plate on the electical connector side slide the plate back into place.
15. install the stator making sure to remove any old grease on the cable end and replacing with new grease
16. On the board with the brushes there are a set of points make sure to hit them with a points file or sandpaper before reinstalling.
17. lightly clean the brushes with emory cloth making sure not to change the shape.
18 install the brushes into their holders making sure the long slant is furthest from the springs. while holding the brushes in place push the board into place and snap the clips into place.
19. Lightly grease the bushing on the end (do not go heavy, too much can leak on the coils and short out.) and reinstall the plate.
20. reinstall the two bolts and if desired wire wheel the metal contact area on the case.
21. reinstall into the vehicle.

please note because the case needs to be grounded its a bit tougher to test off the vehicle.
 
Cool.

Pics are good.

A link to this in the tail gate thread would be good.
 
I melted the resin out of the windings on mine. Nothing could help that. Switch stuck in the up position and I did not notice it.
 
Cool.

Pics are good.

A link to this in the tail gate thread would be good.

x2

Look in the "tech articles" section of the forum. I started a "tailgate" thread. Copy and paste your info and/or add your pics there for future reference. Try and keep all the info in one place so it's easier to find down the road.

(link to specific article) http://coloradok5.com/forums/showthread.php?t=296615

FWIW there is a lot of other good info in that section if you have some time to look through some of the articles. Feel free to add info to related topics in there or start one if there isn't already.
 
Question: How fast should the motor turn and should it turn by hand?

Note that I have a broken cable so I put the 6 in piece in the motor slot to try to turn it and I could barely move it.

Since my tailgate motor is not currently installed I took it apart, cleaned it up and put it back together. I grounded the case and hooked up one of the leads to the positive terminal on the battery and the motor turned really slow. Tried the other terminal and it was the same deal, slow. I would assume it should turn somewhat fast with no load on it. In doing so, it almost melted a 14 gauge wire to the battery terminal. Yeah it was redneck but I don't have a switch in the Blazer right now (it didn't come with one). :doah:

Is that normal for the tailgate motor? I may just buy a rebuilt motor depending on your answer.
 
Question: How fast should the motor turn and should it turn by hand?

Note that I have a broken cable so I put the 6 in piece in the motor slot to try to turn it and I could barely move it.

Since my tailgate motor is not currently installed I took it apart, cleaned it up and put it back together. I grounded the case and hooked up one of the leads to the positive terminal on the battery and the motor turned really slow. Tried the other terminal and it was the same deal, slow. I would assume it should turn somewhat fast with no load on it. In doing so, it almost melted a 14 gauge wire to the battery terminal. Yeah it was redneck but I don't have a switch in the Blazer right now (it didn't come with one). :doah:

Is that normal for the tailgate motor? I may just buy a rebuilt motor depending on your answer.

both of mine turned fairly slow, but it looks like thats because they are designed to have a decent amount of torque. they should turn very easily by hand if not clean the old grease out as well as cleaning the bushing surfaces and re-grease.

if you havent already i would clean off the copper on the communtator since if its not getting a good current it will cause it to spin slower.



Also sorry everyone for the delay in pictures, wound up being rather busy the past few days. will try to add them tonight.
 
Sorry for the delay guys photos are now in the pdf
 

Attachments

  • rear motor rebuild.pdf
    1.3 MB · Views: 56
Any measurements of the brushes so new ones can be sourced?
 
Any measurements of the brushes so new ones can be sourced?

i actually have not, i'm planning on trying an upgrade on the motor so i will take some measurements when i open it up again.
 
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