1951 Chevy Accessories Installation Manual

Figure 223
10.  Cut the manifold to windshield wiper motor tube 1 inch from dash mat in the drivers compartment and insert "Y" fitting. Take the remaining large diameter tube and run from the "Y" fitting to the upper fitting on the windshield wiper control mounted on the instrument panel.
11.  Remove windshield wiper control knob from instrument panel by loosening set screw and remove dummy plug as shown in direction of arrow, replace with valve push rod and reassemble, (see figure 224).
Figure 224