The Stovebolt Site Forums The Shop Area General Truck Talk vacuum wiper motors

A couple of easy steps to try before sending yours out for a rebuild. Often what is wrong is the lubrication has dried up and hardened and/or the seal has dried out. First make sure the motor armature is moving if you haven't already by grabbing both arms and gently moving them a cycle or two. If it moves OK put the switch in the OFF position, pull the vacuum hose free of the manifold. Make sure the hose is in good condition (no splits). With the end free from the manifold squirt some WD40 down the hose and work the arms a few cycles. This should pull the WD40 into the housing and soften the lubrication. Once the armature is moving freely pour some brake fluid in the hose and work the arms a number of times. If the seal is only dried out this will soften it and allow it to seal again. The brake fluid won't harm the rubber hose but don't spill any on your paint! If you're lucky you'll have wipers working as well as new. I'm not the originator of this idea but a number of folks have tried it and it often works to rehabilitate "dead" vacuum wiper motors.