My experience with disassembling vacuum motor wipers is that repairing them is beyond my skill level and rebuild kits are not available. I'd recommend you send it off to Rob Fiken at Fiken Wiper Service That's what I did, and it was money well spent.

Kevin
1951 Chevy 3100 work truck
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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.