Technical Mk1 55 alternators gone - bad luck or inevitability?

[(CZ)enda]

The first alternator packed it up at some 190 000 km. It seized, the pulley would not turn and the part of the housing on the pulley side cracked. So far, so good, nothing lasts forever - I got another one from a scrapyard the same day, it worked OK. A week later it was gone and looked exactly like the original one - seized, cracked housing. Both were standard Magneti-Marelli alternators and the belt was never overtensioned.
I gave up and bought a brand new one (HC Cargo, which, according to the dealer, was supposed to be made in Denmark - no way, it says the dreaded "Made in China" on the box).
The question is - what caused the same defect on the two alternators? Was it just a bad luck, or is it common once the car hits this mileage or age (my Punto is 1996)? I would understand the seizing (although the bearings did not make any funny noises before the failure), but the cracked housing is weird.

 

[s and b]

they seize whilst stood
used to have to change lots on mk1 puntos as they had been stood waiting insurance clearance
ive also had to chuck them out after being at work in my bat cave ,sometimes they can be freed off with a windy gun but usually its best to send them to china
your new in china one should be sound i have one fitted to my truck from china and its good quality

 

[DaveMcT]

When bearings seize they can spin and this can crack the housing if its thin zinc alloy used on most accessory parts. With any unknown used alternator its best to change the bearings so at least you know its mechanically good.

A high mileage casing can crack simply due to fatigue stress. Who knows how old the used spare was.

 

[Ziggy122]

Just Poor luck im affraid

Mk1's are getting old cars - still see alot around tho

A new one is way forward tho

ziggy

 

[(CZ)enda]

Thanks to all, that was quick The Punto was, indeed, sitting motionless for maybe 2 months.

 

[Ziggy122]

2 months could do it easily - the Tension of the Belt holds the bearings in a Set position
So it gets "stuck" as it hits that point = Wear = Failure

My Bad luck with alternators has got worse My Voltages have started to drop yet again

ziggy