alternator

hi all, bought my defender 110 just about three months ago, previous owner fitted a new alternator, gave me reciept etc. it has been stood for last two weeks whilst i waited for parts to be delivered etc. it fired first turn of key but i noticed that the guage was reading low so i did a test and its producing 12.91 volts at high revs, is this enough? right parts changed on engine are timing belt, exhaust and front pipe. just looking for a bit of advice. thanks LEE

no that voltage isn't high enough, sounds like the alty has failed. Check wires, belts, etc.

checked wires belts etc, all seems fine. is there a regulator that can be changed or is it a new alternator? thanks LEE

check also the light bulb (battery light) in the dash hasn't failed - if it has the alty wnt charge.

There is a regulator/rectifier pack in the back of the alternator but if you've got the receipt then take it back - a lot of places will have a warranty, some even more than 12 months.

To be honest, i personally have never rebuilt an alternator, but thats always been because whenever they have failed i've always seemed to manage to find a bargain on a new/spare 'un.

Okay bulb is okay so it's not that. whilst i have the reciept its of no use because i live in france and alternator fitted in UK, i personally have only rebuilt one on a mercedes van because it was 500 euros for a new one. just wondering if there is anything that could be blowing alternators, two in three months smacks of a bit excessive, any thoughts anyone Thanks LEE

Hi Bev,
Probably a short in the wiring or if it was a reconditioned unit perhaps it wasn't a quality unit. You might check the earthing is excellent all the way through from the Alternator mounting bolts, Engine to Chassis and then from that point through to the Battery -Ve post, it might be that when you start it it's working OK, but with a lower current the connection's not so good. This is a long shot as starting problems would be the first symptom of this type of problem, but there's no downside to checking this side out thoroghly. Clean em & grease em!
Good luck,

bought a new alternator and fitted it and was charging me batts at 14.9v lovelly..then 2 days later down to 11.4v and batt light on dimmly took it back to shop who checked it and the alternator just wasnt putting out the volts required so they gave me another new one..seems ok now,so even new ones can fail