I have already done the intermittent wiper upgrade using mid '70 F150 parts back in '05. Click Here if you want to see this upgrade.
The wiper linkage and bracket was taken apart and bead blasted, etched primed, painted and greased. The original rubber grommets between the motor and bracket were hard as a rock and deteriorating so I used regular grommets that were intended for wiring for replacements.
I notice one of the wires feeding the switch got pinched sometime in the past so I decided to replace the pigtail with a better harness