Recommissioning a 480: 4. Wipers

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davekit
Started learning about 480
Posts: 60
Joined: Sat May 14, 2022 11:16 am
Location: Bradford, West Yorks

Recommissioning a 480: 4. Wipers

Post by davekit » Tue May 17, 2022 4:46 pm

The wipers took ages to sort out. The switch for the rear wiper was completely seized. I found the cover would simply pull off, and I could then spray switch cleaner onto the switch itself. The switch eventually freed up, but the wiper still did not work. In fact, there was not even a voltage at the wiper. About this time, I got the repaired CEM back, so checked everything again. Still no movement, but there was 12v at the wiper.
I removed the motor from the tailgate and tried connecting the battery directly to the wiper motor, and was surprised to get brief movement. Reversing polarity got brief movement in the opposite direction. It surely wasn’t meant to work like that? I could have simply bought another motor at this stage (and hoped that worked), but decided to strip the one I had.

I removed all the accessible bolts, but could not find anything wrong, so removed the cover from the motor/gearbox. This entailed drilling out the rivets holding it together, hoping I could get it back together if needed. With the cover off, the problem was revealed. The motor shaft had floated out and stopped the crank from executing a full cycle. Pushing the shaft back in restored order, but for how long? Clearly this was a design flaw. I stripped the crank and put a disc of 10 thou (0.25mm) brass under it, the disc being large enough to partly cover the motor shaft and prevent it from floating out again.

To reassemble the motor cover, it was necessary to drill and tap M3 holes to take countersunk caphead M3 bolts. These minimised the height above the cover to prevent possible interference. For the same reason, nuts were not used, but threadlock was applied to ensure the bolts did not work loose. Putting the motor back on the tailgate, I am pleased to say that the rear wiper now worked, and REL 6 in the CEM could be heard switching every 6 or 18 seconds, depending on the switch position. So, three different faults contributed to the rear wiper not working!

The front wipers worked on two speeds (and stopped!), but the intermittent wipe did not work. I tried another motor, which was smoother in operation, but still no intermittent function. Not too important, but I found a solution on the forum. Early cars, like mine, had a feature that made the wipers go from intermittent to continuous on full throttle, controlled by the throttle cable. It proved unreliable and was eliminated on later cars. The forum suggested joining the tags together to restore the intermittent function. So I joined the tags on the cable. No change. It was many weeks later that I realised I must have misread the instruction. Joining the two wires which went to the throttle cable was what was required. Result! Fully functional front wipers to join the rear wiper.

Washers worked from the start, but the level warning light would not go out. On examination, I could not see how it had ever worked! The tags appeared to be permanently connected together, and there was no switch function on the float. Most odd! I disconnected the wiring as a solution!

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