FredR

As I understand I have a diode problem on the alternator of my Turbo S. As I understand these alternators are liquid cooled and to date I have not been able to find a source for a replacement diode or diode pack as the case may be. I understand there are 6 diodes mounted on the alternator.

Much appreciateif anyone can advise what the situation is or whether I need to bite the bullet and source a new alternator.

v10rick

Do you have alternator rebuild services there?

Not for the diodes but to compare the cost of a rebuild to a replacement.

Santacruz

One of the main things to cause diode problems, would be the rectifier.
So you would have to source a rectifier as well as 6 new diodes.
For diodes, someone like Mouser, DigiKey or RS components.
Then it would be a good time to maybe change the bearings.
In the long run, I would think a rebuilt or new replacement would be the best option.

Jfrahm

The diodes as a group make up the rectifier. One pair of diodes for each phase.

v10rick

"So you would have to source a rectifier as well as 6 new diodes"

Are you referring to the voltage regulator? The diodes make up the rectifier.

Santacruz

Yes, my bad. The voltage regulator.
Although in the business we used to refer to it as the diodes or bridge rectifier and the voltage regulator as the rectifier.
My fault, I should have been more clear.
However, if the 'Voltage regulator' goes bad, then that can damage the diodes.

FredR

Gents,

Thanks for the inputs to date. I have a local source that can strip and rebuild alternators at very cost competetive rates.

My assumption is that I will need a complete bolt in module of some kind if I can determine the part number and who makes/supplies such. It may even be possible to replace a failed diode again if the part can be identified.

I traced a source in the UK who offers a rebuild service and approached them to see if they can supply me the parts I may need but no response to date. The problem with a UK based rebuild is getting the core back there and then getting it returned over here. Airfreight is not exactly cheap and two trips would probably cost more than the rebuild itself. However the diode pack must be very light therefore easy/relatively cheap to ship out.

Identifying the correct part and who can supply it is the trick bit or so it would seem and that is principally what I am looking for intel on. I have not seen anything to suggest a problem with voltage regulation.

v10rick

Diodes fail for a reason.

Could be an issue with the alternator windings, regulator or ? It was reported on this forum that the regulator is not available separately.

Because of the rather extensive labor to swap it out I would replace it with a new one.

There have been reports of remanufactured alternators failing prematurely.

Jfrahm

I've had them start to pass current, possibly just due to age. Can cause a pernicious battery drain.
Voltage regulators... I am OK replacing any that are no-name or cheapos from a rebuilt alternator. OEM ones are often very robust. these days I'd be worried about the quality of a replacement part, or if it's even genuine. Might have my druters getting a used factory alternator and changing the brushes if they are half worn or more.

Dilberto

^ this ^