The 1956-1962 Corvette Wiper Arms were cable-driven from the Corvette’s Wiper Motor. A drum behind the firewall rotated multiple cables to each transmission. Fortunately, these transmission cables do not require adjustment on a regular basis; however, when adjustment is needed, either from cable stretching or following a new installation, Chevrolet designed a system where cable tension can be increased by simply pressing on the outer end of the transmission shaft.
To illustrate, each transmission has two spools – one for each drive cable. The inside face of each spool has cast teeth locking them together. When the transmission shaft is pressed down, the two spools separate and an internal spring allows the spools to rotate to their tightest position. Once pressure is removed from the transmission shaft, the spools are locked together again and the cables are tight against the wiper motor drum. When removing the transmission, the operation will require the help of an additional person. With one person pressing down on the wiper transmission shaft to “unlock” the spools, the second person (inside the Corvette) must pull against the cables, rotating the spools against the pressure of the spring. Once all the necessary slack is obtained, the wiper transmission shaft can be released and the spools will lock together. This slack will allow the cables to be removed from the wiper motor drum. The Corvette’s Wiper Transmission can then be removed.