Sprague air wiper surprise

[Iceni John]

This evening I discovered a quirk with my Sprague air wipers.   If there is less than about 40 PSI feeding them, they don't turn off!   I had filled my accessories reservoir from my onboard electric air compressor, and I was trying to see if a small Norgren inline lubricator mister could be connected to the wiper motors to keep them lubricated (nope, it won't work on my bus because of how their air lines are connected).   I had shut off the compressor and was using the remaining air in the system, but when I turned off the wipers they refused to stop working.   Hrumph!   I had visions of Perma-Wipe, with me being a modern-day Sysiphus tormented by their unceasing movement wherever I drove.   I turned on the compressor again, and at about 40 PSI the control knobs' detents for the Park position started working again!   Very weird.

I learn something new every day.   Some days it's not much of earth-shattering consequence, like today, but just when you think something is so simple it could never surprise you, it then turns around and taunts you.

I've been searching for any info or specs on these Sprague wiper control valves, but no luck so far.   Does anyone here know of a website that would have this info?

John   

[Bill B /bus]

First time I've heard of not stopping on low air pressure.

Bill

[robertglines1]

Time to share: asleep in bed middle of night. Air pressure reached a point bleeding off: all of a sudden the wipers come on. at first didn't realize what had happened.  Happened several times until I fixed slow air leak.  For what's it worth.   Bob

[Iceni John]

Thanks, Bob.   You've restored my sanity  -  I thought I was losing my marbles when my wipers did that.   It's a good thing the horn doesn't have the same quirk.

Oh yes, I've found a way to use my Norgren lubricator for the wipers.   I'll use it for one motor, and I'll buy another for the other motor.   There's no way to have one lubricator for both motors, because the motors' air lines come off the washer control valve;  if I put the lubricator there I may get oily water coming out the nozzles!   I think that would be Not Good.

Thanks, John