Electrics: 164: Bosch part number for alternator

[Pigeon]

Anyone got the Bosch part number for the alternator on a 164 - or for the rectifier pack off said alternator? My rectifier pack is dying and I need to check out replacements.

[GEORGEROV]

Hi Pigeon, Bosch alternator No: AL77X , might find numbered as #5/241735..

[Derek UK]

You might like to check out this company for parts. I got some small parts for a 35amp one from them. Quick and a good price. They will deal with the public but I'd advise you to know exactly what you want before you ring them. Good luck

http://www.woodauto.com/default.aspx

This is for 164

http://www.woodauto.com/Component.aspx?Ref=EXA238002552

[Pigeon]

Cheers all...

Further investigation has revealed it was not the alternator...

There are two types of rectifier pack that alternators use - a twin-output rectifier with separate positive outputs for D+ and B+, and a single-output rectifier with a blocking diode to isolate D+ from B+.

With the twin-output type D+ and B+ are at pretty much the same voltage, but with the blocking-diode type B+ is at a voltage one diode drop lower than D+. Therefore the two types need different, or differently-adjusted, regulators.

The symptom I was observing was that D+ was regulated to a precise 14.4V but B+ was sitting at around 13.3-13.5V... consistent with a twin-output rectifier with one diode dud.

However, it turns out that I have a blocking-diode rectifier but a (non-original, Lucas) twin-output-type regulator.

So the simplest solution turned out to be to fit an extra diode in series with D+, to subtract a diode drop from the voltage seen by the regulator from D+ and thereby make it match the voltage on B+.

With the extra diode fitted it is now providing 14.2V on B+ and I am a happy pigeon.