Date: Sat, 17 May 2003 15:08:43 +0000 (UTC) From: Joe Morris <jcmorrisnopsame.org> Subject: Re: Washer Check Valves - give me some theory
'nuther Bob <nonenopsam.com> writes: >However, that does not seem to be the way the Saab wiper check >valves work. You can't blow through them in one direction. What >gives ? How do these things work ? If you're asking the question, I'll assume that you're looking at them because one or more of the water jets isn't working. The check valves have spring-loaded plungers; the pressure from the washer water pump has to overcome the spring's force before water can flow from the supply line to the nozzle. A couple of years ago I lost my windshield sprays and replaced the check valves; after disassembling the old ones I found that the plunger material had apparently degraded and eventually adhered strongly to the valve seat. This adhesion was enough to prevent me from opening the valve by blowing into the assembly. Joe Morris