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D2 - Common Faults Quick links to all known common faults and their solutions

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Old 29th May 2010, 03:33 PM
B@fink B@fink is offline
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Default D2 Wiper issues investigation

This is not a how to guide, its an investigation into a possible cause of the wiper failure on D2 A8's. Please don't use/treat this as a how to as it isn't a comprehensive strip and rebuild guide, its just the steps I followed to try find out what is happening.



I'll start with the wiper assembly already removed from the car. I found this quite simple to remove, just a collection of 10mm bolts and 2, 13mm nuts holding the wiper arms on. It's a bit of a squeeze getting the assembly past the wing and some care is required to prevent the paint from getting scratched. I also had to remove the bonnet strut and support the bonnet independantly to get the unit out.



Next I removed the "c" clip holding the spindle in place (location circled) This has to be done very carefully to prevent it pinging off into oblivion, under which you should find a washer and "o" ring (all arrowed) that hold it all together and in the case of the "o" ring keeps the elements out as the spindle is exposed to the weather under the wiper arms. I next applied gentle pressure to slide the spindle from its bushing, I was careful here to prevent damage and so the spindle didn't fall out and get damaged.



And as you can see the drivers spindle is in rude health with a thin film of grease present and its nice and shiny, you should also find a small shim washer (arrowed) that I assume acts as a slide for the spindle during operation to prevent it burring up.



On to the passenger side and OH NO!.....I think we have an obvious suspect, the washer and "c" clip are still present (arrowed) but the "o" ring has been virtually destroyed by age/wear and that will inevitably be letting water in.



And as I feared looks like we have the start of spindleicide from a combination of corrosion and galvanic action (compare it to the lovely shiny drivers side spindle). The top arrow is where the "c" clip sits on the spindle the washer and "o" ring would be under this and the second arrow clearly shows where the spindle is begining to suffer from pitting of up to 1mm deep. Unfortunately the corrosion products and water will begin to form a gritty grinding paste at this point and will rapidly accelerate the wear until seizure or massive bearing wear in the bronze bushing is inevitable.



And as you can see the bronze bush is beginging to wear from the spring pressure of the wiper arms pushing the worn spindle against it and the start of ovality is present. If left these wipers would be damaged beyond repair fairly soon.

The ideal way to repair is replacement especially if the wear has become too great or you are too late and they have seized up. If you have access to engineering equipment the spindle could be returned to a smooth finish and the bronze bushings replaced or reamed out to straight again. Fortunately the spindle here isn't too badly damaged, the wear is only at the top of the spindle under the "o" ring, the rest of the spindle still fits the bronze bushing correctly and the unit operates smoothly and there is only a small amount of lateral play on the spindle end. I comprehensively cleaned the spindle and bushing out of any dirt and corrosion grit then throughly greased the spindle shaft to lubricate it and prevent any further water ingress. I then replaced the "o" ring with a new one (available from any motor factors eg Halfords) and packed it into plenty of grease to stop the water sneaking in. The drivers side was simply greased and reassembled as this was in good condition. The rest of the wiper assembly is a well designed and sturdy unit and well protected from the weather so I simply regreased everything to keep it working as well as it has for the last 12 years.

This was the only mechanical issue I found during my investigation though I did find a small electrical issue in the form of corrosion on the pins inside the wiper motor multi plug that is quite visible when it is seperated (yellow arrow corrosion, red arrows incate location of fitting bolts).



I simply cleaned this up with a bit of contact cleaner to stop it getting any worse and causing electrical gremlins in the future.

So there we have it, a sturdy wiper assembly brought to its knees by a 10p "o" ring and a bit of water. I hopefully have extended the life of my wipers for some time yet by removing the corrosion products, lubricating the spindles and excluding the water and I will possibly be making this "o" ring a regular annual service item (and definately a service item when the unit is replaced to stop this happening again) as the whole thing took half an hour begining to end. Replacement is still going to be need eventually but not for a while yet now!
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Last edited by B@fink; 29th May 2010 at 08:38 PM.
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  #2  
Old 29th May 2010, 06:50 PM
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Architex_mA8tey Architex_mA8tey is offline
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Excellent write-up B@fink, isn't it amazing how one small part can feck up a much more expensive assembly.
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Old 29th May 2010, 07:02 PM
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Added to sticky. Thanks for the write up.
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Old 30th May 2010, 09:24 AM
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Well written, very comprehensive and very useful!!

Thanks!

Oli
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