So here I am, driving the Plymouth Barracuda home the day I bought it from my brother earlier this year and it starts raining lightly. I try the wipers and they swipe up, then stop. Hmmm. My brother was right, the wipers do need some attention. So a couple days ago I pulled the dash out of the car and removed the wiper motor to see what's up.
Reading about these mid-60's Chrysler variable speed wiper motors doesn't give one confidence that they are straightforward in operation and repair. Turning on the switch starts the motor in forward rotation. Switching off the switch reverses the motor and it comes to a park position. But there is also an internal cam and switch, and an external spring gizmo that also come into play getting the wiper motor to the park position. Below are photos of the cam and spring gizmo.
The motor doesn't work, so I have no choice but to tear the critter apart. First thing I noticed were quite large gouges in the armature commutator. See those ripples in the copper segments? That can't be good.
Fortunately my 1941 Sheldon lathe made easy work of truing up the commutator segments. I needed to take a .010" depth of cut to clean up most of the damage.
Once that was done, I scraped out any debris between the commutator segments with a box knife.
A small gouge remains that didn't clean up during the lathe work but it shouldn't be an issue.
Once the armature was back in the motor, I had a new problem crop up - a broken brush! Oh, bother.
So off to the local electrical store for new brushes (they didn't answer the phone so I just showed up). Unfortunately they only carry brushes for AC applications. The guy was a big help though because he knew of a place 1/2 hour away that carried DC brushes, and they happened to have just what I needed. This next photo shows the new high-copper-content brushes installed. I used silver solder to attach the brush leads, as I didn't know if regular solder might melt due to heat when the wiper motor was running.
I tried using my 260 watt Weller soldering gun but it wouldn't heat the surrounding metal hot enough to allow the solder to flow well. So out came the big gun, Dad's 70-year-old 200-watt American Beauty Model 3158 soldering iron, manufactured by the American Electrical Heater Company out of Detroit, Michigan. It did the trick very nicely, and as an added bonus, it warmed up the basement a degree or two. Just kidding...
Oh, and that cam photo earlier? You need to get the pin on that cam on the correct side of the two tabs on the metal plate that's attached to the nylon gear, otherwise the wipers will park in the "up" position instead of the "down" position.
For my car, the arm coming off the gearbox needs to be poking away from the motor when the motor is in the park position, as shown below. If the arm parks near the motor housing, pop the cover off and move the white plastic cam 180 degrees so the pin lands on the other side of the two tabs.
Once the motor was back together, I bench-tested it and it worked great. Finding the right wiring sequences for low-speed, high-speed, and park though were a royal pain, as most websites' directions were not for an A-body wiring harness so I had to pull out the ol' 1966 Factory Service Manual and look up the appropriate wiring diagrams. Below is what I came up with.
Terminals corresponding to wire colors for 1966 Chrysler A-body (B, C-body in parentheses):
V3 - A - Black (Brown)
V4 - F1 - Red (Red)
V5 - F2 - Yellow (Dk Green)
V6 - P - Dk Blue (Dk Blue)
High Speed Test:
Case to Ground
A to 12v
Low Speed Test:
Case to Ground
F2 to Ground
A & F1 to 12v
Park Position:
Case to Ground
F1 to Ground
A to F2
P to 12v
Simple, huh. Ok, high speed is simple. Ground the wiper case and put 12 volts to the black wire. Not so simple for low speed or park position though. All I can say is, What were you thinking, Chrysler?!?
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