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Working in getting our newest car ready to be driven and I'd really like to have some sort of functional wipers just in case. I have 2 motors, one that came on the car and another I picked up for parts off a $1 table at Carlisle years ago for our Plymouth. Both motors run pretty well after some lubing and I now wonder if the mechanism is causing a drag. Off the car and hooked up both motors work well and seem to move with authority, you can stop them with your finger but it takes some effort. I have right next to no experience with vacuum wipers, so I don't know just how strong they should run. I have added some lube to all the pivot points and have the arms off the reduce drag, how easy should the rectangular tab in the middle be to pivot? I can make it function by hand with just my thumb and index finger, I'm just not sure how soft a touch they should be. Any input before I just sent one of the motors off for a rebuild? Thanks!

Performance of the system is highly dependent on how much vacuum is available. How much vacuum is being supplied to your wiper motor and is the booster pump functioning?

Definitely check the vacuum and also check carefully for cracks in the rubber hoses but most long sitting motors I have played with will move quite well unloaded. As soon as any drag or load is given to the motor by the wiper mechanism it all but stops.

In spite of having adequate vacuum there is still a good possibility the seal around the sides of the paddle which makes contact with the sides of the vacuum chamber has become dried or worn from the constant sliding against the chamber and is not making a tight enough seal to avoid a vacuum leak so motor cannot provide full power. There is also a possibility gaskets have dried and shrunk back enough to provide an internal vacuum leak.

You can try lubing per the instructions on page 52 in the service counselor article entitled Lubricating Windshield Wiper Motorspackardinfo.com/xoops/html/downloads/SC/SC-VOL23NO10.pdf but I would almost bet the motor will require a rebuild before it works properly. You can send it to Ficken Wiper Service and in a fairly short turnaround time get back a motor that runs as new.rebuildingtricowipers.com

Well, got sidetracked by some brake issues and just got back to the wipers. Found someone put a single fuel pump on it, so no extra vacuum there. I was able to get a double pump from the u pull it and will be sending it out for a rebuild. On the pump I found one port had been blocked by pinching oil off on of the tubes. Just to verify the correct numbing is manifold to fuel pump and pump to wipers, correct?

Correct. Manifold to vacuum pump outlet, vacuum pump inlet to wiper motor.

If that missing vacuum pump is the only thing you found wrong with the plumbing I doubt you will see much improvement in the wiper action. Probably 99% of the time the manifold vacuum is all that is used. The strong manifold vacuum keeps the valves in the vacuum pump wide open so the pump cannot work and is effectively just a pass thru section of tubing. When manifold vacuum drops due to load or a wide open throttle to a point it is less than what is needed to keep the valves pulled against their springs the loss is enough to let the valves close so the pump can actually start working. The strength of the vacuum produced by the pump is a bit less than normal manifold vacuum would be and the volume is considerably less than the manifold can supply but the wiper motor does keep working -- usually at a slower speed.

The input vacuum port on the Packard motor is the one pointing toward the passenger side. The port on the drivers side is there to supply vacuum to the optional windshield washer. It is made active by the driver rotating the wiper knob toward the front of the car which is opposite the direction used to turn on the wipers. Knob turned forward and being held against a spring for a few seconds moves the slide valve on the motor to turn on the vacuum at that port. Vacuum to the washer lets the piston in the washer be pulled up against a heavy spring to fill the water end. Releasing the knob lets the spring push the piston down again expelling the water and continued turning the knob in the regular direction starts the wipers.

Ok, good to know and now after further inspection it does have the vacuum booster on the pump, it is a newer pump and the booster is way on the back. To further throw me, the pump has no dome on the top and some undrilled/tapped fitting spots you can see. Anyway, dug out the vacuum guage and I an seeing 20-21 inches of vacuum, so I guess the motor is in need of a rebuild. I'll pull the extra I have apart and look inside to see if I can rehab it a bit. Thanks for all the input. Oh, and I'll put the used one I bought in a bag and keep as a spare/core.

Your conclusion is based on what?