1962 power windows

[Kenneth F.]

About a year ago the pass. side window sash went past the rubber bumpers. Now the driver side just did the same. I noticed that the stop plates had pushed away from the window, and the rear rubber cap had been pushed off. I figured that I could put star washers under the fastener heads to help, and put adhesive on the rubber, but I operated the window with the door apart to see what is happening. I can see the stop assemblies and reinforce bracket appear to be heavily loaded as the upper door flexes when the window sash contacts the stops. The forward window frame appears to be a good fit in the door post felt. I have the convertible top down as I am doing this.
When I got the car, the windows did not appear to have been a problem. When I rebuilt the car, I replaced the old power window motors with new GM motors. I have the container one of the new motors came in with the number GM 4999680. I wonder if the new motors are stronger than the old motors?
Someone suggested that I might try an ignition ballast resister in the window circuit to reduce voltage to the window motors, taking some load off the window stops.
I am looking for suggestions and help.

Ken

[Terry D.]

Re: 1962 power windows

Were the old motors broke? If not what was reason for replacing? Don't have an answer but this will kick it back to the top.

[Frank D.]

Re: 1962 power windows

The window motor power shouldn't be a problem. I run the more powerful SPW motors in my car. But you can't "hang" on the power window buttons either. Get off them when the windows are fully up or better yet, "bump" the switch as they approach the top.

You can't accurately see what the stops are doing with the door garnishes and end caps off as the door does flex. I test them by putting the inner garnish on temporarily with triangular end cap on the car's door and then observing the operation... Test a little, adjust a little, test a little, etc.. A PITA but that's what it takes.

[Richard M.]

Re: 1962 power windows

Ken, This is a common problem of a poor design. The window stops would work better if the stop tabs on the lower channel sash were originally built out more to give the rubber stop more area to contact. Since the rubber is round and the stop contact area is squared it makes for a poor design. Also, the reproduction rubber stop cups are much softer than originals and can slip off of the flat bolt head easier, even if glued on. I also think they're a smaller overall diameter which adds to the problem. Your new motors may be stronger and causing the issue but I'm not sure if dropping the voltage to the motors would help.

Since you've had the stop plates off, be certain they're installed properly. The threaded hole for the bumper bolt is actually offset from center. You want it as shown here. This ensures the rubber stop will be as close as possible to the sash stops after adjustment.


Sash showing the 2 stop tabs. One is welded on, the other is a bent area of the channel. Not much there to contact. I have considered building the tabs out more but never did it. It may be more difficult to install the window into the door.


Stop bolt hardware.

[Dan D.]

Re: 1962 power windows

The upper stop reinforcement was a design change to help with this problem, and for preventing the fiberglass from cracking around the bolt holes. I'm not sure when this change was made, but my 57 (#4122 - late May 57 build) did not have the reinforcements, and the glass was cracked around one of them. I added the reinforcements when I redid the doors. Most of our suppliers have them and they are not expensive.

Even with this change, the stop is marginal at best. The door will still flex some if the moldings are not installed, and it is still possible to defeat it and run the channel past the stop. As Rich says, poor design.

Rich has published an excellent article on assembling these doors - if you don't have it, then download it. I don't really know I could have fixed my doors without it.

-Dan-

[Kenneth F.]

Re: 1962 power windows

Terry, The old motors were working, but I replaced them only because new were available from GM. I still have the old motors.

Frank, I think the only way to avoid putting strain on the stops, would be to stop the window just before full upward travel. It is difficult to time coming off the switch at the right time. A couple times a year, I had to put a thin layer of bicycle inner tube under the garnish molding end cap to keep it from sliding rearward. I did not know at that time why it was sliding, but now I believe it is the strain from the window contacting the stops.

Richard, My stop plates are installed as shown in your photo. The stops are installed as close to the window frames, without hitting the window frame.

Because I believe the windows worked well with the old motors, I wonder if the new motors are stronger? Is there a switch inside the motors that opens the circuit? With all the available modifications available for the C-1, it would be great to have window motors with an adjustable stop on the motors, to eliminate the stress on the door.

I read 16 amps with the window moving, and 23 amps when the window stops moving. The voltage drops about 1 volt when contacting the stops.

Richard I would be interested in your article on doors. I will look in the archives.

If someone knows which Restorer, Mike Ernst's article on power windows is in, I am interested.

Thanks for the great input,

Ken

[Richard M.]

Re: 1962 power windows

Ken I think the article is about window seals/fuzzies, glass replacement and channels. I'm on the road but I'll try to find the link.

Links
https://www.forums.ncrs.org/showthre...pair-Procedure

https://www.forums.ncrs.org/showthre...window+channel

[Dan D.]

Re: 1962 power windows

Ken, these motors have a built-in thermal circuit breaker to open the circuit if the motor tries to run locked rotor. But thermal breakers are slow to react and I don't believe they would react fast enough to prevent the window from going past the stop. Also the rotor has to be locked in order to draw enough current to trip the breaker. Windshield wiper motors are very similar in this respect.

I have measured the run current and the stall current on my motors, but I will have to dig the info up.

These motors are well sealed and unless they have been severely misused they usually only need new wires, which is not hard to do. That's what I did with mine. The insides were in perfect condition.

-Dan-

[Kenneth F.]

Re: 1962 power windows

Dan, I would be interested in your current readings, if they are located. It would be convenient if another thermal breaker could be installed in the circuit, outside of the motor, to open with less current.

Ken

[Kenneth F.]

Re: 1962 power windows

Richard, Thank you for the great articles. Should I have to go into the doors to repair my windows, I can use your information.

Thank you,

Ken

[Dan D.]

Re: 1962 power windows

Ken, I re-measured my motor current for you today.

Voltage was measured at the source (under the hood). I cannot get at the motors as the door panels are installed.

V=12.8 at stall mode.

Right Side:
Down: 13-17 amps
Up: 13-16 amps
Stall: 25 amps

Left Side:
Down: 18-20 amps
Up: 15-19 amps
Stall: 25 amps

The variation in current and from side to side is because the motors labor to get past the fuzzies and channels at different points. These fuzzies were a trip in frustration. I labored to make them work.

My currents are in line with what you measured. The stops held in both doors - at least for a second or two. Did not press my luck.

A separate breaker is not going to buy you anything. It looks to me like the breaker interrupt current is between 20 and 25 amps.

You should be able to make the stops work, or you could possibly modify them per what Rich suggested. These things worked when they were new, and for a long time afterwards. So they should still be able to make work again. That's what I said about the fuzzies, and I won. But as you can see, they are not perfect.

-Dan-

[Kenneth F.]

Re: 1962 power windows

Dan, I appreciate your readings. If you think your motors might be original, it saves me the trouble of installing the old motors. It puzzles me that this car did not seem to have a problem with the window stops before I replaced the motors and fuzzies.

Thank you,
Ken

[Dan D.]

Re: 1962 power windows

I know my motors are original. They were the only good part in the doors. I got countless hours in these things. I made a career out of them.

Even though the currents between yours and mine are similar, that does not necessarily mean they have the same torque. Your new motors may be more efficient. Lots of technology advances over 60 years. The only way to tell is to install your old motors. But that is a labor hit - they are the last thing to come out.

-Dan-

[Kenneth F.]

Re: 1962 power windows

Dan, I guess the only way to know would be to re-install one of the old motors.

Your input helps a lot.

Ken

[Dan D.]

Re: 1962 power windows

Ken, if you can't get the stops to work, then that is unacceptable. Trying to get them down again past the stop could damage the glass.

If the stops worked before and they don't now, then something has changed. Also, a majority of these cars worked without the reinforcements, which is even more stressful on the stops and the fiberglass. By the sound the only thing you have different is the motors.

Every time the window is forced past the stop, the fiberglass is being stressed and will eventually fail. You should probably bite the bullet and change a motor. Its not that much work to pull a door apart, especially when you have done it before and know the ins and outs of doing so.

What do your motors look like? The only bad thing on mine were the wires, which I replaced.

-Dan-