Carbuilder
Gold forum user
- Messages
- 112
This is what I have been up to for the last week and a half.
When I got the car it had 1 speed wipers with no park. I took the motor out while doing all the mods behind the dash; removing all the vent hardware including the blower motor, adding an A/C evaporator, adding power steering. I wanted 2 speed wipers with park, and that is where the adventure began.
I bought a new Lucas wiper motor. I tested it with a new-to-me variable voltage power supply. The motor didn’t seem to work. I took the motor housing off to check things out and in the process broke the phenolic piece holding the brushes. Fortunately that is a replaceable piece, so ordered a new one. With that replaced, it still didn’t seem to work. After a bit of fiddling I realized the ammeter on the power supply was not just to show current, it was to adjust it…it was on 0. I bumped it up and the motor worked.
It took a lot of effort to figure out how to wire it up. I bought new rocker switches that don’t have the same terminal connects as the Lucas wiper switch. Every article I found on how to wire up the motor had different information. I finally found one that seemed to make sense. So with my rocker switch, one 4 terminal relay and one 5 terminal relay, I got it working, including the park. This was on the bench.
Since the motor had different mounting than the one I took out, I found a decent place to mount it close to where it was before. But I had to make a new tubing connection from the motor to the first wiper box for the actuator cable to run in. I did that, tried it, and blew a fuse. I figured that the tube I bent was not bent smooth enough and had too much friction/drag for the motor to overcome. I redid it and blew another fuse. At that point I took the whole wiper assembly out to see how to free it all up. It seemed to me that no matter how smooth I did the bends (with a tubing bender so there were no kinks) it still had a fair bit of drag on the cable. I know it worked before, but couldn’t get it to work now without blowing a fuse. I took the motor off several times to confirm it worked.
Getting frustrated at this point, I bought some metric tubing to replace the stock parts. The metric one is 7mm ID, which gives about .020” increase in diameter. Not a lot, but it did allow bends that had the cable moving without any drag inside it. Of course the outer diameter was 10mm (too large to fit in the wiper boxes) so I lathed down the end of each one to fit. There was enough wall thickness to get it to almost the diameter of the stock tubing. With it all assembled it blew another fuse. Just how free does this cable have to be?!
The one issue is that to get from one wiper box to the next the cable/tube has to go around the large circular duct in the middle of the dash. This is for fresh air into the blower motor. Since I wasn’t using that and getting really fed up at this point I took a saw and cut a large chuck out of that round duct. I have to seal it up at the top anyways since it serves no purpose now with the A/C taking up all the room. That allowed me to use a tube that was perfectly straight in that section, with no bending to go around the duct. Blew another fuse.
Not pretty, but got the job done and won't show when the dash is in:
The only thing left was the section from the motor to the first wiper box. I was having trouble bending a piece of tube to fit without any forcing at all. Could that be enough drag to stall the motor and blow a fuse? Apparently so.
Final step. I made up a piece of tube that clamps in the wiper box and goes to the motor, but stops an inch short. I figured that allows the tube to move a bit, but still guides the cable. It seemed very free to me. Blew another fuse. Pulled the motor off the mount and tested it……works fine.
I put the motor back in, but left the wiper cable out so it was just the motor, not driving anything. Blew another fuse. I pulled the drive gear out of the motor so it was just the motor with the worm gear on in, not driving anything. Blew another fuse. Sat back, did some thinking, and came up with what it must be. The motor works fine when sitting on the floor mat, but blows a fuse when mounted. So mounting it, which grounds the casing to the car body, shorts it out and blows a fuse. No idea why, but that seemed to be it.
I took the motor out and did some testing with an ohm-meter. Yup, the “hot” wires (the red and yellow ones, for the 2 speeds) were connected to the motor casing. So when the motor was mounted, the hot wires were connecting to the ground directly. Power it on and of course a fuse blows. But why is it like that? I had a really good look at the connections and couldn’t see anything wrong. I figured I might as well take the motor casing off to see what things look like inside, even though I knew that couldn’t be it. Took the casing off and found this:
When I first replaced the brush mounting piece and put it back together, the rubber grommet was out of place and the wire was pinched against the casing. Fixed that and everything OK. Put it back in the car with everything hooked up and the wipers work, including park.
Wow, what a journey that was!
Rick
When I got the car it had 1 speed wipers with no park. I took the motor out while doing all the mods behind the dash; removing all the vent hardware including the blower motor, adding an A/C evaporator, adding power steering. I wanted 2 speed wipers with park, and that is where the adventure began.
I bought a new Lucas wiper motor. I tested it with a new-to-me variable voltage power supply. The motor didn’t seem to work. I took the motor housing off to check things out and in the process broke the phenolic piece holding the brushes. Fortunately that is a replaceable piece, so ordered a new one. With that replaced, it still didn’t seem to work. After a bit of fiddling I realized the ammeter on the power supply was not just to show current, it was to adjust it…it was on 0. I bumped it up and the motor worked.
It took a lot of effort to figure out how to wire it up. I bought new rocker switches that don’t have the same terminal connects as the Lucas wiper switch. Every article I found on how to wire up the motor had different information. I finally found one that seemed to make sense. So with my rocker switch, one 4 terminal relay and one 5 terminal relay, I got it working, including the park. This was on the bench.
Since the motor had different mounting than the one I took out, I found a decent place to mount it close to where it was before. But I had to make a new tubing connection from the motor to the first wiper box for the actuator cable to run in. I did that, tried it, and blew a fuse. I figured that the tube I bent was not bent smooth enough and had too much friction/drag for the motor to overcome. I redid it and blew another fuse. At that point I took the whole wiper assembly out to see how to free it all up. It seemed to me that no matter how smooth I did the bends (with a tubing bender so there were no kinks) it still had a fair bit of drag on the cable. I know it worked before, but couldn’t get it to work now without blowing a fuse. I took the motor off several times to confirm it worked.
Getting frustrated at this point, I bought some metric tubing to replace the stock parts. The metric one is 7mm ID, which gives about .020” increase in diameter. Not a lot, but it did allow bends that had the cable moving without any drag inside it. Of course the outer diameter was 10mm (too large to fit in the wiper boxes) so I lathed down the end of each one to fit. There was enough wall thickness to get it to almost the diameter of the stock tubing. With it all assembled it blew another fuse. Just how free does this cable have to be?!
The one issue is that to get from one wiper box to the next the cable/tube has to go around the large circular duct in the middle of the dash. This is for fresh air into the blower motor. Since I wasn’t using that and getting really fed up at this point I took a saw and cut a large chuck out of that round duct. I have to seal it up at the top anyways since it serves no purpose now with the A/C taking up all the room. That allowed me to use a tube that was perfectly straight in that section, with no bending to go around the duct. Blew another fuse.
Not pretty, but got the job done and won't show when the dash is in:
The only thing left was the section from the motor to the first wiper box. I was having trouble bending a piece of tube to fit without any forcing at all. Could that be enough drag to stall the motor and blow a fuse? Apparently so.
Final step. I made up a piece of tube that clamps in the wiper box and goes to the motor, but stops an inch short. I figured that allows the tube to move a bit, but still guides the cable. It seemed very free to me. Blew another fuse. Pulled the motor off the mount and tested it……works fine.
I put the motor back in, but left the wiper cable out so it was just the motor, not driving anything. Blew another fuse. I pulled the drive gear out of the motor so it was just the motor with the worm gear on in, not driving anything. Blew another fuse. Sat back, did some thinking, and came up with what it must be. The motor works fine when sitting on the floor mat, but blows a fuse when mounted. So mounting it, which grounds the casing to the car body, shorts it out and blows a fuse. No idea why, but that seemed to be it.
I took the motor out and did some testing with an ohm-meter. Yup, the “hot” wires (the red and yellow ones, for the 2 speeds) were connected to the motor casing. So when the motor was mounted, the hot wires were connecting to the ground directly. Power it on and of course a fuse blows. But why is it like that? I had a really good look at the connections and couldn’t see anything wrong. I figured I might as well take the motor casing off to see what things look like inside, even though I knew that couldn’t be it. Took the casing off and found this:
When I first replaced the brush mounting piece and put it back together, the rubber grommet was out of place and the wire was pinched against the casing. Fixed that and everything OK. Put it back in the car with everything hooked up and the wipers work, including park.
Wow, what a journey that was!
Rick
