How to fix your rear wiper motor assembly

Mine quit working after 4 years & 44,000 miles. Unfortunately, I ordered a new unit before I removed and tore into the old one.

What I found was that the main wiper shaft had frozen, due to the elements, into the 2 inch brass sleeve it rotates in.

After removing the assembly from the vehicle, remove the black stamped steel cover that is held by 8 T20 screws. Next tap the shaft through with a hammer and a punch. It will eventually push through with the two large tooth gears still attached. I removed the gears, but you may not have to. Then I cleaned up the shaft with some WD40 and 400 grit sandpaper. And I sprayed copious amounts of WD40 through the brass sleeve. Then I put anti-seize on the shaft and ran it in and out from both sides several times, wiping away the excess WD40. Then I reassembled it with anti-seize on the shaft and under the little plastic bushing at the outside end of the shaft.

Take note of the gear tooth orientation and do not lose the o-ring that sits beneath the plastic bushing on the end of the main shaft. Also, notice there is a plastic cap/bushing on the inside, capping one of the shafts. Do not lose this.

I tested mine with a 12v source to the red and black wires on the white plug. It appears to be working fine, although I did not reinstall it for a complete test.

I wish I would've done this before paying $170 for a new unit!

Can you return the one you bought?

Yeah, who knows, that might have been what was wrong with mine also. I had the new part and just threw it in...only took about 15min. Good to know though, as these don't seem to last more than 40k or so, I might have a chance to repair it the next time it seizes up. Especially living in the salt infested winter environment of upstate NY.

Nah, already installed it, so I guess now I have a spare! Hope this helps others though.

Thanks for posting this. I knew, at worst, I'd be out $170 when I took the wiper moter off and cleaned it up. I was happily surprised to find everything in working order upon re-assembly. Your posting was critical, so thank you very much! Two hours of my time was well worth the attempt. Made my weekend ...

You are welcome guys. Glad to see the info was helpful!

I was up late last night trying to test this. Theres a small module right at the rear wiper. I found polarity change going into the module, but the three wires coming out of the module never changed polarity, so im concerned that the seized woper shaft has caused the module to fail. Im goin to try rebuild the motor tonight. Just got a price from Ford of $350 because the module only comes with a new motor. <Fingers crossed>

Just got done rebuilding the motor. It works! I bench tested it before hand and nothing. Afterwards, it works like a charm. As long as the little module isn't burnt up, should be good to go. Can't wait to get home and try it. My GF owes me big time. Appreciate you shaker...

Question: Mine does not work unless I wiggle it. . . . then it starts working. Any idea what might cause this ?

I bet its the shaft that the wiper arm attatches to. I would take the motor out and rebuild it using shaker's instructions. Mine was so bad inside. Im sure yours is just getting caught up.

GFs Truck said:

Just got done rebuilding the motor. It works! I bench tested it before hand and nothing. Afterwards, it works like a charm. As long as the little module isn't burnt up, should be good to go. Can't wait to get home and try it. My GF owes me big time. Appreciate you shaker...

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Sounds like your GF owes shaker!!! :

How do I get to the wiper motor?

Does the plastic on the hatch just snap on and off ?

JCat said:

How do I get to the wiper motor?

Does the plastic on the hatch just snap on and off ?

Click to expand...

IIRC there are 3 or 4 small plastic tabs holding the cover on. Try releasing them gently with the aid of a thin blade or screwdriver. I broke off one of mine. Pop off the cap on the wiper arm and remove the nut retaining the arm. Pry off the arm and remove the plastic cap over the nut that holds the entire assembly to the glass. Then there are a couple silver screws to be removed with a nut driver inside the plastic cover. Going on memory here...

My replacement (rebuilt from Rock Auto) motor crapped out after only 6 months. I'm starting to think it 'might' not be the motor. I actually watched it slow to a halt when I turned it on yesterday. I'm going to take it apart and see whats going on per shaker1's instructions above.

Mine did the slow movement about 2 inches and froze today. I hear the click, does that mean the plastic module that the power wires plug into is still good?

Gonna have to get to the motor and have a look as well.

I took mine apart and tapped out the shaft. Man, was it seized up. The bad news is that after I reassembled it and tested it, no go. I might get another rebuilt one, and before I install it, I'm going to take it apart and make sure the shaft is clean and lubricated with anti-seize.

Update...it works!! Don't try and test it with the liftgate ajar. I took it apart and re-tried it with the liftgate closed and it worked great. Thanks shaker1 for saving me more than 100 bucks.

edwx said:

Don't try and test it with the liftgate ajar. I took it apart and re-tried it with the liftgate closed and it worked great.

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After rebuilt it still seized on me. Got a refabed one online...started getting pissed when it didnt work so I checked this site again.

Had the glass liftgate open...duh! Closed the glass works perfect now.

Mine just quit after 117K miles. Took it apart, and the shaft was seized in the sleeve, cleaned it and greased it, works fine now. I am surprised the resistance did not blow the fuse or motor.

Thanks for the advice guys. My rear wiper just seized up and I knew where to look for the answer. The bushing on mine appeared to be steel. The shaft was all pitted which cleaned up easy but the question was how to clean the inside of the bushing. I used a pistol bore brush in .380 caliber. I couldn't believe the amount or rust I got out of it. Lubed everything and now it works fine.

shaker1 said:

Nah, already installed it, so I guess now I have a spare! Hope this helps others though.

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Helped me - thanks Shaker!!

I replaced the wiper assembly about 18 months ago and it seized up again today. It only came with a 12 month warranty so I decided to try your fix. What a PITA it was to remove the shaft from the assembly - I ended up bending my punch tool. I really didn't think after all this trouble it was going to work, but it did! I have a feeling it's a temporary fix, but at least my wife will have a rear wiper tomorrow, which is good because we're finally getting some rain here.

Next project - the spark plug replacement!