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This weekend, I took the pump that failed last weekend apart, to find out why it died.
The flexible braided wire that feeds power to one of the brushes broke off right at the brush! As near as I can determine, it was an assembly error. The brush wire should have been routed between a couple of brush retainer features on the end housing. Instead, it was routed to one side such that the wire was being jammed by the brush retainer. Not enough to cause an immediate problem but the extra stress did it in after 6 years of use.
The commutator and brushes looked like they had a lot of life left. The shaft at the upper end by the brushes was showing some wear but the other end with the pumping elements was fine.
The pump was externally & functionally the same as the one from my wife's '88 BMW but internally much different. (Wife's pump failed at 80K after 12 years.) The pump elements were the same but the commutator, brushes & shafts were smaller on the newer one from the Volvo. My wife's pump failed because a connection to one of the commutator segments opened up.
I would say that both pumps failed early because of process or workmanship issues. If they had been properly assembled, they would have lived much longer. Because of the differences in failures the symptoms were different. My car died with no warning while my wifes's complained for several weeks before it refused to start one morning, (at home in the garage luckily).
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'96 965 at 89K. Had '85 745 Turbo Diesel for 200K.
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