OK, I dug out my spare motors. Neither of them really held vacuum, but one was one that I sent to Fiken for him to scavenge parts from. It was missing the switching mechanism and some of the unique screws. I didn't really expect him to return it to me. Anyway, I plugged the inlet nipple, and applied vacuum across the on-off slide switch of that one and it would pull up to 15 inches of mercury and then slowly leak down. If I applied pressure to the top of the slide switch, helping it seal against the body, it would do a bit better (slower leak down.) There's another leak path at the direction switching mechanism where a toggle slides across three ports to connect the source with either side of the paddle. When the wiper is in park, the flow path is thru the slide switch, directly to the park side and the seal that's on the paddle, and bypassing the switching toggle. In any case, unless there's significant deterioration in the motor, I don't think the loss of vacuum would really be enough to affect engine performance. The lubricant in them is kind of a waxy stuff that should help seal the slide switch and the toggle (the vacuum itself should hold the switches against their seats on the motor body.)
Attached are a few pics I took to show the inner workings of the motors.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
