The rubber pedal pump on my '72 250 was shot internally with rubber particles constantly plugging the nozzles. I plumbed in an electric pump, from a late '80s Chevy Cavalier, made a bracket to mount it above the original washer pump and wired it to the pedal switch wiper activation circuit. I also had to eliminate the two-way valve on top of the washer bottle, run the original hose direct from the bottle to the electric pump, then a second hose from the pump, back through the firewall, to the nozzle connection. Also wound up disconnecting the wiper motor wire from the pump pedal switch due to feedback from the new electric pump keeping the wipers running all the time, but they still work normally from the stalk-switch - a small sacrifice to have a really effective washer.

Alternately, it may be simpler to mount the electric pump underhood, leave the OE pump swich alone and wire a separate (and fuse protected) push-switch in a convenient spot under the dash.

Happy Motoring, Mark

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DrDKW