plane fixer Mine do that same way,have cheated my way home in a shower by turning on and off as I go. Might give the unit some hydraulic jack oil,it really helped my vacuum brake booster. I tested it on a wheel cylinder cup,did not hurt the rubber. If the wiper has a leather sail in there it might like some lube. Got another unit in my pile,might try that oil on it to see if it will help. Been hot and humid for weeks really slows you up from doing much.
