I did a wiper refurbish on my 66 122s. Thanks to Ron K for the helpful illustrated guide on his sw-em website. Symptoms were the wipers acting like they were straining to move at all, barely making it across a 16-inch arc, if that much, and when you shut them off, they stayed six or eight inches up off the bottom of the windshield. High speed was about the same as low speed, very slow. Once I used them for 30 minutes and I could smell stuff burning. At home I touched the motor housing and it was very hot. I spit on my finger and touched it, and the spit instantly vaporized. Like a frying pan for teryaki.

Once into it, with the whole shebang on a bench (my bed with a white rag on it), I saw nothing tight or seized. Neither wiper shaft seemed anything but okay, and the apparatus once freed of the motor rocked back and forth smoothly and easily. I took the motor apart and found that grease had migrated from the gear housing down through the little wire-passage hole into the body of the motor, and from there into the brushes. One brush barely moved when I pulled the endcap loose from the armature. Probably had been arcing.

I cleaned the inside of the motor with brake parts cleaner, including the end cap and the brush holders. Lots of grease mixed with black brush debris ran out. I kept the end cap warm overnight (on a warm woodstove) to dry out the felt that I hope is still around the brass bushing in the endcap.

By this time I had handled the unit enough that I had broken the brush lead that held the endcap to the motor housing. And there were bare spots on the wires leading from the gear housing into the motor body. The insulation seemed feeble and oil-soaked, whether from my handling or from the previous 43 years I don't know.

Reassembly I put some air-tool oil (3 drops) onto the area around the endcap bushing...trusting there might be some felt in there to hold it. I sanded one side of the one brush (still tight in its now-clean holder) until it flipped easily backward and forward like its mate. I rocked the commutator in a strip of sandpaper held in the web of my hand, and blew off the little copper particles. Not a lot of sanding, just a little cleanup.

At the gear end I used electricians tape to wind the bare spots of wire where they went through their hole. I thought about soldering copper beryllium onto the one worn contact point on the gear cover, and I didn't after I saw I was going to have to mail-order for the stuff, if I could get it at all. The right way...was not fast enough for me. I hope I don't regret that later. I took out the nut that held the gear in place, after marking the location of the gear-gap relative to the rotating arm on the shaft. I cleaned out the old grease and sanded down the inside of the housing a little because the gear rubbed somewhere when I turned it by hand. After sanding, it still rubbed. So I left it. I had to torque it to make it rub, and I hoped that normal use would not do this.

More brake-parts cleaner for the gear housing, followed by a wipe-down and a shot of compressed air. About that time I discovered the thin white fiber disc that sits on the end of the endplay screw, and I wondered why the compressed air hadn't shot it into the sticker patch next door. I was glad. Then new grease packed in behind the gear and into the worm-drive tunnel, and more grease (it felt wrong but I did it) on the contact plate side of the gear, and on the contact plate itself. I used axle grease. Motor back together, I soldered some fittings on the ends of a ten-inch number 10 stranded copper wire for a ground strap and fitted it on a through-rod. I had noticed the ground strap was broken off when I took the thing out.

All re-installed, it works great. Regrets? I pried off a wiper arm with the end of a box wrench and got hold of the little pot-metal thingy that the arm goes over, so I now have one of those that isn't swaged on to the shaft, and might fall off one day. I have fixed a similar problem on another car by hammering the thing on with a couple tiny strands of copper wire laid carefully in place to make it all very tight. Maybe this one will just stay together by itself. So far so good.

I have a high-tech tip: For end play of the worm gear (armature shaft) I ran the motor by itself (free of the wiper rods) and then screwed in the end-play adjusting screw until the motor slowed, then backed it out until it sped up to full speed again, and then gave it another one-eighth turn out for clearance. 4 to 12 thousandths, there you go. (guess)

Virtually a new set of wipers. I celebrated by buying rubber blades and driving around in the rain. I drove to the dog park after dark in a downpour and walked around with the dogs and got soaked, and felt jubilant.