On rack and pinion type wiper setups, any crud or muck in the axle boxes, axle shafts or on the rack itself can cause heavy current draw from a wiper motor. A high current draw through a tired/high impedance battery can cause a large system voltage drop. The signs are that the wipers are "lazy" getting going, and if you see your headlamps dim briefly when you first start the wipers.
Things to do:
- completely discharge your battery overnight by wiring a headlamp bulb across it, and then re-charge it fully. Do it a few times over a month.
- top up your battery fluid before and after charging.
- check your charge circuit and fan belt tension to make sure the alternator is being driven correctly.
- clean battery contacts and grease them with vaseline.
- take off the wiper arms, unbolt the wiper motor and withdraw the rack cable with the motor. Careful you don't kink it, and make sure you unplug the power connector first. Clean the rack with white spirit and a rag. Regrease it with CoppaSlip or low-temperature grease.
- rotate the wiper axles to check they are free moving: if they're not, short of removal and a complete clean up there's little you can do. If you can dismantle them, clean and re-grease them. Alternatively, spray a bucket load of WD40 into them any way you can.
- re-assemble the rack by re-inserting the cable and wiping off the excess grease: re-connect power and check the axles rotate. If OK, replace the wiper arms.
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One of the few remaining Mk1 owners...
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