hey guys i have a 4905 1970 with air windshield wipers and washer just going thru the bus and pinpointed a small air leaking coming from the washer push knob so i removed it with the air line still attached and i see and feel a small hole of the face of the switch and it seems to be drilled out?? why would any 1 drill it out?? and what is the best way to fix it? Tap and drill a cap on it ?its only smaller then a 1/16 of a inch very small ?? any ideas john
John
I can't help you with the hole or the reason for it, other than to tell you that the PO of mine put a shut off valve in line under the dash so they didn't leak anymore.
Every once in a while I will forget to close the valve after using the wipers and the air leaks like crazy. If you can't repair the leak at the knob, the shut off works well when you use it.
JimCallaghan
The hole may allow the pressure to exhaust once the knob is released to allow the washer to cycle ready for the next squirt
John, if it helps, my 4107/4903 manual shows the wiper valve as a Sprague Devices GFD-122-105; and the washer valve as a Sprague Devices W-26-9. I checked the Sprague website, but their search by product line doesn't seem to be working right now. NAPA perhaps?
Arthur
John,
As Tony said, the hole is there as an exhaust port.
A simple fix is to take valve apart and clean it or remove the fittings and squirt WD40 into them and work the valve. Do this over and over until the liquid running out is clean.
I would say to use BrakeKleen, but I'm not sure if that would dry out the o-rings too much.
Most of the problems with air wipers and washers are caused by contaminated air and lack of maintenance.
Dallas
GO BUSSING!
thanks guys for the info !! but know i think it was drilled out after the fact the hole that was drilled was drilled over some ## is this what u would call a fix or a just in case or the washer fluid was not working properly?not bleeding properly?
I think it needs O rings. They will also sometimes leak if not turned all the way on or all the way off. On my fleet most of the wiper problems are from lack of use. Take the feed line off and pour it full of air brake alcohol. Let it run with the arm off for a few hours or run it for a while with the hose on the window. Most air motors will bypass air at the lowest setting, if I'm loosing air the wipers are always the first thing I check to be sure they are all the way off.