[Mgs] MGB alternator

[Paul Hunt]

12k isn't far at all, on a 'normal' car that is barely a years driving.  If 
you replace just the diodes then there could be something else wrong with it 
that is causing the diodes to fail prematurely and it will happen again. 
OTOH if you get a rebuilt that came in with faulty diodes they may only have 
replaced those and done a quick voltage and current check (perhaps).  I'd 
prefer to keep original, so unless this is the second or more *replacement* 
set that has failed, I'd change the diodes again in the hope that the 
previous set was a rogue, otherwise get a rebuilt.

Incidentally what type of diode pack is it?  If it's the earlier type with 
the nine visible diodes on large cooling plates, as opposed to the 'solid' 
alloy housing with cooling fins, then it could be vibration causing the bond 
between diode and plate to fail.

FWIW.

PaulH.

----- Original Message ----- 
>  After 12,722 trouble-free miles, it seems the diodes are perishing again 
> in
> this two-wire Lucas alternator.