Dis-assemble them, clean them and lubricate them with fresh lubricant. Personally, I like some of the synthetics like Dow Corning O-ring lubricant. It won't thicken in colder temperature so the wipers will work in all temps.
I have always had success taking them apart. Make sure you check any inlet or outlet tubes going into the motor. Mud wasps normally like to curl up in there and die, blocking the tube.
|