Last night I cleaned off my overloaded workbench, dug out my service manuals, and lined up three spare wiper motors I have in my stash. Right now the wipers in Peer Pressure are defunct, after three years of working without a problem.The stopped working when I was in Chestertown killing time with Brian waiting for the welder, and I got stupid and started fooling with the bulkhead connectors.

My troubleshooting workflow should look something like this:

  1. Pull the cowl cover off, disconnect the power lead to the motor, and test it for power.
  2. Check the bulkhead connector for power.
  3. Test the switch on the dash.
  4. Pull the motor itself, pull it apart, and see if it’s seized up.

But, because time is limited, I’m a curious guy, and I frequently do things out of order, I decided to pull a few of the motors I have apart to see how they work. I’m starting with one very clean motor and two that have more miles (and grease) on them, but all three are identical. I cleaned the gunk off two of them, cracked the manual, and got started.

Wiper motor surgery 1

Disassembly starts with the switch side, where the arm connects to the housing. Pulling the top off the housing reveals two contacts and a gapped brass plate, which is how the the motor handles delay. Under the plate is a round plastic toothed gear which fits into a worm screw connected directly to the motor itself.

Wiper motor surgery 2

Pulling the cover off the other side of the motor reveals both brushes and the commutator, and inside the housing, the field coils. The clean motor looks almost brand new, while the second one contained the amount of dirt I’d expect from a 30-year-old truck.

Wiper motor surgery 3

I left all the grease in place, closed the motors back up, and decided to wait until I pick up a cheap battery charger to bench test everything with 12 volts. Harbor Freight has one for $20, which fits my budget perfectly, and I may run out and pick it up this weekend.

Date posted: November 2, 2012 | Filed under Repairs | Leave a Comment »

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