Alternator alternative to original

[AdelaidePagoda]

It would appear my original 59 year old alternator has finally stopped working. The local repair shops are finding it difficult to source parts to repair it. They say it needs a full refurbishment. I am happy to replace it with another model whilst the original is being refurbished which looks like it will take some time. I do have a few Questions:

1) Does anyone know the best place to source internals of a Mercedes 230 SL Alternator Bosch 0120400504 Generator 1963-1965? See photo
2) Does anyone know of another suitable model that will be able to replace it whilst I await refurbishment? Perhaps another model of Mercedes?

Many thanks, Dave

[lpeterssen]

Dear Friend

In my opinion the best bet is to go for Bosch AL69X, this is an alternator you can find everywhere, which has internal regulation instead of external as original pagoda alternator.

This one has externally the same appearance as original, and on the back has just two connections for “0” shaped standard terminals.

On one terminal you will place the T30 large gauge cable, and on the other the blue cable that comes to your external voltage regulator.

As this alternator produces 80A, you need to bring one thicker t30 cable to the connection hub that goes to the starter t30 terminal. Original cables are 4 mm2 to the cabin loom (directly to main light switch, you may leave that one as is) and another 4mm2 cable to the connection box on the fender or below the oil pan that later brings power to starter.  This loom will be have to be changed to a larger diameter cable, at least 8mm2 to bring all that excess juice to your battery through the existing connection battery/starter.

Is just a 700 mm section, so if you buy 1 meter of larger cable you are good to go.

Best regards
L.Peterssen

[450sl]

If you are going for a rebuild ; be sure to have the diodes replaced by original ones.

These are pressed in,  to ensure good heat dissipation witch is vital.

mark

[AdelaidePagoda]

Lpeterssen, is the AL69X compatible with a 230sl that previously had the 35 amp Alternator? Or is that the reason for all the additional upgrade to the wiring?

Is there a new Bosch 35 amp version to make this process easier with less wiring upgrades?

450SL, thank Mark, if I can get the new parts, I will be sure to do that.

Dave

[lpeterssen]

Dave

I was trying to look for a new alternator in the 35A range and was not able to find one.  There should exist but are not easy t look for them with the search engines.

The upgrade you have to do to the wiring is minimal.  Just the 300 mm section from the alternator to the junction box, and then another easy segment from the junction box to the starter which is about 700mm.

Those segments are independent from the main wiring. You can keep the original wiring and just add this complementary wires in parallel so that harness does dot fry with the increased energy capacity of the alternator.

Keep looking maybe you find a classic bosch alternator catalog which I didn’t look at.  If so, place the link and I will look through the pages to recommend you another one that may also fit.

Best regards
L.Peterssen

[lpeterssen]

Go to this page.  I think I found it there 35A alternator.  This is a company specialized in refurbishing alternators in Germany.

https://www.rg-gmbh.de/en/lichtmaschine-bosch-instandgesetzt-35a-0120400700.html

Enjoy it.  Only 89Euros

[450sl]

good find lpeterssen ; but almost looks to cheap for a rebuild with new diodes. better to check first.

[AdelaidePagoda]

Thanks lpeterssen, this is very useful.  Agreed, this is very inexpensive for what it is. I will make enquiries.
Does anyone else have a recommendation for a new readily available 35 amp Bosch alternator?

[lowpad]

Bud's Benz has several options: https://www.budsbenz.com/catalog/230-250-280-sl/b-electrical-ignition. I purchased a rebuilt 35A model and it worked fine.

[dirkbalter]

Has a core charge though.

[AdelaidePagoda]

lowpad and dirkbalter, thanks for the tips, these are very helpful guides. I will investigate further and report back.

The pelican one will require some modifications as mine is the original three pin alternator, not the newer plug version.

[AdelaidePagoda]

To close the loop on this one, I had the good fortune of meeting Stephan at Gullwing on the Gold Coast Australia last week. Given his extensive experience with all things classic Mercedes, he was able to find a suitable refurbished 35 amp 14 V 1964 Bosch Alternator.
I have since had it fitted and it works perfectly!
Many thanks Stephan, you are a gentleman and I will be sure to recommend and utilise your services in the  future.

[mauro12]

How about this germany company for only 89€? Reliable source ?