By: Corky Guenther

When I bought the B, one of the first things I discovered not working was the windshield washers.  Not that they were required much, just that they didn’t work.  You know me, of course, that just wouldn’t do.  The washers in early Bs (through Model Year 67) are not electric but rather use a mechanical pump which requires pushing a plunger in the dash.  This pump draws fluid from the reservoir through a check valve into the pump when the plunger is released the fluid is then expelled through the nozzles onto the windshield when the plunger is depressed.  Pretty straight forward.  That’s the theory anyway.  It has been too long and I don’t remember the details but I recall having to use at least two check valves in order to achieve functionality.  But, it did work.

Now as I put the dash together, I pushed the plunger or at least tried to.  Maybe it’s just the frailties of age (HORRORS!!!) but I could not easily push it through its functional range.  I looked at Moss and discovered that the $26.00 pump was Back Ordered.  I remember reading on the MG Experience that someone had converted their pump to actuate a momentary push button switch and installed an electric windshield washer pump.  No details, just a statement.

And so…..

The pump I have has a plastic body with the back panel containing the two connectors for the input and output tubes glued into a recess of the body.  The one pictured at Moss has a metal body with the connector panel crimped into the body of the pump which may be a more original type.  I don’t know.  At any rate, I needed to disassemble the pump.  If I ruined it I could always order a new one, nothing lost.

I started by running a sharp pick along the joint between the connector panel and the pump body.  I was able to eventually separate the connector panel from the pump body which allowed disassembly.  The pump is comprised of a rubber bulb compressed by the plunger but reinforced by a substantial (at least to my fingers) conical spring.  I believe that the bulb has stiffened with age accounting for the difficulty I have pushing it.  That’s my story and I’m sticking to it!  Now, to mount a switch.

First, I needed a momentary pushbutton switch that would fit in the pump body.  Looking at the local parts houses, I found lots of toggle switches.  I found at NAPA, a momentary push button switch PN 786139 for just over $5.00. It mounts in a ½” hole.  The back of the pump body has a groove so I figured I could make a disk to fit the groove and mount the switch in the disk.  The groove diameter seems to be 1-29/32”.  So to fabricate, I cut an oversize 1/8” aluminum disk using a hole saw.  Then using a flat head ¼” machine screw as a mandrel chucked in a drill and a rough belt sander I reduced the diameter to “close” then chucked it in the drill press and using a file “sneaked up” on the final dimension.  Then, when I test fitted the disk in the groove, I found that it did not fill the groove completely resulting in fore and aft play.  Fortunately, and I don’t remember why, I have some (close to 100 if you need some) size -29 1/8” square section O-Rings 1-1/2” ID x 1-5/8” OD.  Just the right size as it turns out.  With the switch mounted and the disk snapped in place, the pump body can be mounted in the dash.  It looks stock and now all I need is a windshield washer pump and some tubing.  I think NAPA has those too.  I presume that I can push the switch.