Early FJ40 wiper motor restoration

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Hi everyone!

I am trying my hand at complete wiper motor restorations, which I may start offering as a service. Since this community has helped me so much, I thought I would show my process so anyone can attempt it if they want. If you are interested in having me do this for your unit, feel free to reach out!

This particular unit belongs to @65swb45 so thanks to Mark for sending this out!

This process is pretty straightforward, but can involve some soldering (if you need to replace your brushes), body filler (depending on how bad you metal is damaged/how particular you are about surface imperfections), and painting.

I will post as I complete the different steps. Feel free to leave comments/critiques as I am certainly no pro.

Pictures of previous finished work here: SOLD - Buffalo, NY: 68-74 FJ40 Wiper Motor restored - https://forum.ih8mud.com/threads/buffalo-ny-68-74-fj40-wiper-motor-restored.1288400/
 
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Part One: Tear Down

Lets look at what we have.

Immediately, I noticed that Mark sent me a very nice core. Rubber on transmission rod is almost perfect, no major damage to any components I can see so far. Typical degradation on the wire connector, but that is easy to replace. The original parking switch cover is still there and in amazing shape!
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Removed park switch cover to inspect mechanism. For those not aware, the park switch is the mechanism that allows the wipers to return "home" if you turn off the wipers before they are finished completing a full rotation. Coolerman has a great discussion of how it works here: Wiper Wiring Science - http://www.globalsoftware-inc.com/coolerman/fj40/5G.htm

You want the coppers arms to be straight and aligned so that the middle arm grounds to the bottom arm and there is a gap (blue arrow) between the top arm at rest. The park plunger (circled in red) will ride on the drive gear and bring the middle arm into contact with the top arm during travel.

Lots of times, the park switch cover is lost and these arms can take damage.

This one looks straight as an arrow so lets press on.
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There is an insulator/cushion that protects the wires going to the brushes. Usually these are beyond repair, but this one is decent. I usually replace these with a grommet from the hardware store, as I do not know a source for the original part.

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Removing the rotor cover reveals no obvious damage to the rotor or stator. Someone please correct me if I'm wrong, but in this case the stator would be the metal housing and permanent magnets mounted inside. There is also a race (yellow circle) in the top for one end of the rotor (red circle).

The rotor contains the windings and copper contacts for the brushes (purple arrow).

WARNING: The end that goes into the housing contains a ball bearing (light blue circle) that is not captured and almost certainly will get lost. It can be stuck in the old grease inside, or possibly come out with the rotor just long enough to bounce on the floor and out of your life. I'm sure they can be replaced, but I am not sure of the size.

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Inspecting the bush holders

These look good, but I have seen wipers where the whole thing is melted!

Schematic here: http://www.globalsoftware-inc.com/coolerman/fj40/Page5GImages/IMG_2487.jpg

Notice the lead for the high speed brush (orange circle) is almost touching the front of the housing? These brushes are significantly worn and need to be replaced.

The common brush (blue circle) is also stuck and would not contact the rotor.

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De-solder the parking switch leads

These must be removed to thread through the hole in the housing. You can do one of two things:
1. Heat with a soldering iron and pull
2. Use a solder wick as pictured (How and When to Use Solder Wick - https://www.digikey.com/en/blog/how-and-when-to-use-solder-wick)

Whichever option you choose, avoid applying heat for too long, as this will quickly melt the insulation on the wires and possible damage the insulating material between the copper arms of the parking switch.

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BAG AND TAG

This is absolutely necessary if you plan on doing this project over time. Let me tell you from experience: when you take something apart, YOU WILL forget how it goes back together. Write everything down and keep it in a plastic baggie with the part. Lots of times, orientation of a part is very important but easy to screw up when reassembling. Notice how I included the little bump out at the bottom of the wire connector in relation to how the wires are attached.

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Time to crack this baby open

I removed the cover for the motor side of the unit. I refer to the other side over the driver as the driver side.

This is pretty typical of motors that haven't been opened in years if ever. The original grease/cosmoline is always hardened and gross. This will need to be replaced with fresh white lithium grease. Notice the paper gasket on the underside of the cover. If possible save this at least for a template.

Remove the small white nylon grease retainer thing (light blue circle) as well as the clamp holding the drive connector to the housing and bag them.

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This part is the worst

I hate this part with a burning passion. It is time to remove the circlip that keeps the drive arm inside the outer brass tube on the motor cover. This is the post that the wiper arm attaches to. There is no good way to do this (as far as I know) and 8/10 you will cut yourself jamming tiny screwdrivers in there. 1/10 you will succeed in getting it off, only to have it fly off and land the next state over. 1/10 times it will be just fine.

Notice there is some slight spalling on the part of the drive arm right above the groove that holds the circlip. I had to file this down in order to get the arm out of the housing.

Nota Bene: There is a shim (very thin washer) that goes between the gear and the brass tube on the inside of the cover. There are a bunch of these in the motor, and they can very easily get lost and/or stuck to old grease that you throw out. Be very careful when taking moving parts out, and write down what goes where.

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Remove internal linker arm, main gear, etc.

Remove the parts in the diagram, taking note how many shims are where. The amount of shims has differed from motor to motor, so it is probably not super critical.

Inspect the main drive gear and stacked drive gear for damage. The drive gear is partially composed of a softer fiber material, likely as a sacrificial point of failure (ie if the motor gets jammed you don't burn it out/start a fire this one gear just fails)

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When you remove the gears, you will notice a few things.

1. Blue circle: inside of the plunger that grounds the parking switch
2. Orange screw: holds the parking switch assembly to the housing
3. Red and green arrows: Two slotted screws that hold the copper arms of the parking switch to the housing. Red has a very stupid, very tiny nut that has no real function since the housing is threaded anyway. You will probably lose it, but make sure it does not end up floating around in the inside of the housing.

Remove parking switch, making sure to keep the parts together as they should be.

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Disassemble the drive side unit

Same deal as before. Keep track of shims, yada yada. Remove the other circlip and curse the gods both living and dead.

Note: There is no paper gasket on this side for some reason. Either the factory didn't put them in, or every single unit I have looked at has lost them.

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65swb45

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What Mark said.

You thinking only older wiper motors? I’d have one from a 1980 to send you over the winter while not driving


Guess I been at this too long. When I bought my first FJ40 these were still being installed at the factory. TNK were the old wipers.
 
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What Mark said.

You thinking only older wiper motors? I’d have one from a 1980 to send you over the winter while not driving
I have a 64 fj40 with the two separate TNK wiper motors. They still function, just poorly! Anyone have experience with individual/company that refurbishes these?
 

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