Well I've had a broken rear wiper motor on my 03 Expedition XLT 4WD 5.4L for some time now. When it first broke I noticed how hard it was to move the wiper by hand with the window up and away from the motor. Anyway now it's a while later and I want to prepare for the new motor by taking a look at the shaft assembly for the wiper. When I started it was almost impossible to move the shaft at all. I could barely move it with a 10” adjustable wrench fitted around the square tab that mates up to the motor. I disassembled it and thought I'd take some pictures and jot down some notes to help someone else in the future.

Before replacing a motor this should be step number one. I'm sure many motors are burnt up by doing four times the work it should by moving gummed up shaft assemblies back and forth.

1. After removing the wiper arm there is a plastic trim ring hiding a 22mm nut. Remove the nut and the windows handle can be removed.



2. On the inside of the window there are two 11mm nuts holding the shaft assembly to the window. These two nuts attach to a bracket that’s glued to the window. The nuts cover two huge holes. I guess to allow lots of adjustment.



3. Once the shaft assembly is removed the there is a circlip on the exterior side of the shaft. Remove this, a washer, and a o-ring and you'll be ready to remove the shaft.





4. The shaft on my truck was pretty corroded in. The bracket of the shaft assembly seems to be cast aluminum so I was afraid of breaking it. I moved the tab, opposite the side shown, to 12 o'clock as the assembly lies. Then I opened my bench vise just bigger than the tab so I could tap the shaft straight down and be as supported as possible. I definitely had visions of the bracket breaking but, as stiff as the shaft was, it came out without too much hammering.

5. Once out I cleaned the shaft with steel wool. The barrel had a lot of that white aluminum corrosion. I needed a round wire brush to clean out the barrel in the bracket. I thought a gun cleaning wire brush would be perfect. I don’t own a gun so I purchased a pistol cleaning kit from Walmart (Winchester #99726) for $8. It had the perfect size wire brush. Well after lots of scrubbing with WD40 the barrel was finally cleaned out. At this point the shaft moved freely with almost no effort.

6. I coated the shaft and hole with Mobile 1 5-30. Now I'm ready to buy the new wiper motor.

I hope this helps someone who's having problems with the rear wiper.

 

Nice write-up.

 

Well here it is 5 months later and the rear wiper is not working again. The wiper arm is very difficult to move by hand and the motor absolutely cannot move it. I guess I'll disassemble clean and re-lubricate again. It's not that hard to disassemble... just a pain.

 

I just installed a motor from Oriely in my 99 navigator. It was $39 brand new. If its the same price for yours. I would just get a new one. They require a core FYI.

 

The problem isn't the motor per se, it's more a problem with the bracket that holds the rear wiper arm. The shaft, that the wiper arm mounts on, gets gummed up with corrosion and gets very hard to move. When it gets this way the motor has a very hard time moving the arm if at all. Eventually the motor will fail and if something isn't done about the corroded shaft. By the way I'd love a $39 motor, but the 03 rear wiper motor is $103.

Anyway after I cleaned up the shaft my rear wiper is working again.

 

this doesn't have much to do with repairing the rear wiper motor but I got mad at people driving to close behind me. so what I did today was take the sprayer end off my rear washer fluid tube (in the top tail light) and stuck a basketball inflater end into the tube so when I hit the rear washer it'll spray who ever is tailgating me. I want to remover the rear wiper arm now so it doesn't turn when I use the sprayer. my problem is when I took the nut off the arm is still stuck on unless there's something else holding it on.

 

I had same issue as Punchback on m 2003 Expedition. The wiper blade would hardly move by hand when disengaged from motor (by opening the rear window). I disassembled the mechanism like Punchback. It was corroded badly. I used sandpaper on aluminum shaft and round file for brass bushing. I degreased well with solvents. I then coated with marine outboard waterproof grease. I reassembled and all is fine. My motor is working fine luckily. So zero cost other than my time. Hopefully I will get a couple years out of this or more. This truck has done us well.