Info: Alternator Discovery D1 300 TDI

[Zakros]

Hi All, I just been few a mess trying to solve an electrical problem, so I thought I post my problem and solution:

Just before I headed off to Cape York, the tachometer started playing up jumping around etc. The alternator was still procedure about 13.2 volts so I though not a problem. During the trip the alternator change from 12.5 volts to 13.7 (multi meter sitting on my dash) and last week the battery light came on after a few high revs from starting and the volts drop to 12.2.
The problem was that my newly rebuilt (14 months old now) alternator wasn’t rebuilt that well and was the cause of all my worsening problems.

Solution: New Alternator from Magneti Marelli model number MXA831. The Alternator cost $475 from a local auto elec, I pull out and replace the unit myself. Now checking the volts out is 13.7 that changes maybe 0.1 volts.

Cheers
Zakros

[hook]

14 months out of a rebuild, you did good.
I had mine done, lasted less then a month.
went for a brand spanker and that fixed it.

[justinc]

I never rebuild them anymore.

The quality of some of the internal components are such that it isn't economical to do this. You can really only replace bearings and brushes, reg and rectifier before it gets too close to new price to be worth it, as the rotors on these can fail too. I have also recently seen a stator winding short out and that was actually a part that was very expensive:o The cost of a rebuild v's the new one isn't worth it now for these particular units. Back in the old days alternators were only 35 or 45A and the heat generated was far less, they would do a lot more work before dropping their bundle.

JC

[awabbit6]

14 months out of a rebuild, you did good.
I had mine done, lasted less then a month.
went for a brand spanker and that fixed it.

I'm pleased I didn't rebuild mine then if they don't last. It turned out that a brand new one wasn't much more expensive anyway.

Unfortunately, I replaced my alternator unecessarily. :mad: My fluctuating charge voltage problem turned out to be a dodgy earth strap. It tested prefectly, but when I replaced it just to eliminate it when the alternator didn't fix the problem, charging voltage returned to 14V. The most frustrating part was that I had all the parts I needed to make a new earth strap so the solution to the problem actually cost me nothing.

I guess the positive side is that I now know my alternater is good and I have a spare!