‘52 Cadillac Window Motor

[Fleetwood Meadow]

I can already hear the condescending responses but let me ask a dumb question.. the Motovator motor that turns on when the window switch is pressed is not working. It was working when the car got parked in November. The motor is essentially a starter with an oil pump style gear that pumps the brake fluid into the window cylinders. It spins freely by hand and I can feel the resistance when I am spinning it and it is pumping the fluid through it. But when I pressed the switch it activates the relay and I heard the click and it spun a small amount. I took the battery out and charged it and put it back in the car. I hit the switch and it spun a small amount and now it only clicks like a car would when the starter isn’t getting enough power. I put a jump lead from the body of the motor directly to the negative battery terminal and then a lead from the positive terminal to the relay. It clicks and does nothing but then I see some smoke in the motor. So now the question, what is the problem and how do I fix it? Is it the relay? Is it the brushes? Do I need to fight and take the motor out of the car or can I fix it in the car? Or worst case, do I need to disassemble the plumbing and electrical to it and get it rebuilt?

[Joseph P. Indusi]

I would start by making sure every connection is clean with bright metal to bright metal at each connection.   The bolt holding the ground strap to your motor could need attention as described above.  Next I would move on to the brushes that may be accessible with motor in the car.  Even though you can spin the rotor by hand if the bearings or bushings are worn the high magnetic fields in the motor may cause the rotor to contact the field poles.  

I think this was the last year for 6 volt system for Cadillac.  

Good luck and come back with the cause and repair. 

Joe

[TerryB]

This won’t fix your problem but it might help you out.

[Bhigdog]

You might as well pull the unit and check and/or fix it right.

Be advised when the unit was built a special smoke was built in. The smoke cannot be replaced. If you let too much of the smoke out the unit will not work anymore.

Dont let any more smoke out........bob

[Fleetwood Meadow]

lol clever bob. But what am I "fixing?" I'm not sure where to start. It worked 4 months ago and hasn't been used since then. Is that relay (I call it a relay but it probably has a better term) working properly if you hear the click or is that irrelevant?

Thank you for the pictures Terry. 

Joseph, when I connected a lead to ground it nothing changed so I'm assuming that grounding isn't an issue. I also jumped that relay to see what it would do and it just clicked.

[Bhigdog]

If you are letting the smoke out, sum ting wong. Unlikely the relay. Pull it. Clean it. Check the brushes and commutator. Good time to turn the commutator and replace the brushes. Look for toasted windings. Check the bearings. Bench test. All should be ok upon installation. If not, at the very least you have a known good unit that likely needed service anyway........

Bob

[Fleetwood Meadow]

I went out and checked the connections again and attempted to spin it. This time I got about a turn and a half and then I could hear a gurgling/bubbling sound and the side of the motor was warm and the ground wire was warm so I think I have to concede and take it out. Because I heard that sound down near the windings I’m thinking it needs to be rebuilt. More than likely it is coincidence that it doesn’t work now. It hadn’t been used since 1976 and I got it to work for 2 days then it sprung a leak in a line so I left it until this week when I fixed the broken pipe under the seat. 

[Friartuck]

Brushes hitting a tarnished spot on the armature? Lightly sand the copper segments on the commutator.

[certjeff1]

I have rebuilt quite a few of these over the years what you have nothing more than a modified Delco Remy starter with a solenoid mounted to it. Similar to what your car uses. Just because a small amout of smoke has come out does not mean it is bad. You could still have another problem. Disconnect the copper strap from the solenoid to the motor post. Ground the case, put power to the stud and see what happens. If you still get little to no movement or smoke then yes you have a bad motor. Why did it go bad while just sitting? Cant entirely answer that until you open it and see what is wrong.

Edited March 1, 2019 by certjeff1 (see edit history)

[Fleetwood Meadow]

With it all apart I didn’t see much of anything jumping out so I cleaned the metal between the windings, the armature, and the metal where the brushes rise (the name of that area escapes me.) I took the brushes off and cleaned them along with the area that they sit. I also retwisted the wire connected to the brushes. I tested the continuity and things seemed different than I had expected so I took the housing from the parts car and tested it and it seemed right. I cleaned that and put it on and tested it and sure enough it worked. So I went to put it in and when loosening the nut on the relay it snapped the stud. Since the original relay worked I started taking off the broken relay only to snap the bolt in the housing. So it all had to come apart. I put the other housing back on and closed it all up. When I tested it the pump ran very quickly and shot fluid out of it. So back in the car it went. 

[Fleetwood Meadow]

I turned on the pump and found a broken line right at the firewall so I replaced that and put every window up. They went up very quickly. The driver’s rear window stays open 1/2” though. The underseat cylinder sprays fluid when it’s fully extended. 2 of the other cylinders leak slightly down themselves also. I’m hoping that if I use them a little the rubber will swell inside and they won’t leak. 

Edited March 20, 2019 by Meadowfleet (see edit history)

[Fleetwood Meadow]

After using the underseat cylinder a couple times the gasket inside must have swelled because it doesn’t leak anymore.