Vacuum wiper motor

Larry in Ark.

Junior Member
Working on Trico vacuum wiper motor. When it's on the car with a steady 19" of vacuum according to my gauge, I can't get it to move. With it still on the car I hook a hand vacuum pump to it showing 10 - 11" of vacuum, and it just moves back and forth fine. I don't understand it. Any ideas? Can someone explain to me why it does this???
Thanks. Any help is appreciated.
 
Try the hand pump up to 19 and see if it stalls.
Remove hose from wiper, disconnect metal vacuum line from manifold, run a skinny mechanic's wire up through metal piping and then blow it out. Might have restricted flow from insects or leaf rollers inside pipe.
 
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When you are checking the vacuum do you have it hooked up with a "T" ---perhaps there is a restriction somewhere between the engine and the wiper.
 
Thanks for the responses. I took a direct line from the manifold to the wiper and it works great. Also took a wire and air and went through the lines inside the car. They are clear. But when I hooked the wiper back up to the hose going through the car to the manifold, it won't work. I've got reproduction hose and lines and I'm wondering if they are the right size. I don't know if there are specs on the original ones or not. The hose makes 2 90 degree turns, one out the windshield, the other back to the wiper. Would this have anything to do with my problem?
Thanks again.
Larry
 
Another thing to look at is the compression fittings on the metal pipes, perhaps they have crimped the pipe, or the holes in the fittings were not drilled properly.
 
Try this. Use 3 and 1 oil. The original Trico oil is similar to 3 and 1 oil. Hook a rubber tube up to the wiper and manually work the wiper blade (you can leave the motor attached to the car). This will cause the wiper to "suck" though the rubber tube. Put the end in some 3 and 1 oil (pour some in a small cup) and suck some into your wiper motor. Inside your motor is a leather rectangular "paddle" that swipes in a semi arc inside the half circle case. The oil helps to keep this paddle pliable which provides a better seal between the paddle and the case.
 
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