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Discussion Starter #1
I have been having intermittent blinking *battery* warning light on the dash. Forum said alternator dying.
Bosch water cooled alternator is replacement unit, no repair parts available. But, how much different can it be than other 150amp alternators?

Decided to try and fix it.

Removed alternator, takes about 30 min including draining the radiator. Drain coolant, remove shroud/fan, remove drive belt, 6x10mm, pry and alt is out.
To disassemble alternator, took off alternator center pulley bolt, positive terminal nut, and 4 torx bolts holding the plastic top cover.
Installed new Voltage Regulator ($60 on eBay, search for "Water Cooled Alternator Regulator") same way i removed it, and checked the diodes.
There are 3 positive (smaller) and 3 negative diodes. Two of my negative diodes were bad (no resistance either way), pressed in new ones ($4 each), and soldered them in.
Diodes are "Bosch type press fit 1/2" 50amp".

Put it all back together and now I am getting constant 14.60v charge :clap:
 

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Great repair job! How much do you think you saved? I'd guess $1k or more since the price of a new alternator is nearly $1k itself (most online suppliers are selling remanufactured ones for under $500)!

So you replaced your regulator with a new one and the diodes and that was it?
Where did you get the diodes?
Do you have a part # for the diodes? I think I might replace all of the diodes while in there when I re-do my alternator. I've got 80k miles & 7 years, so I expect it'll go soon if I don't.

Thanks for the success story and very valuable tech tip! :clap:
 

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Discussion Starter #3
Generic rebuilds are about $500, lowest around $300 after core refund....but i figured it can't be that hard to fix.

Diodes look like this:


Bosch style (generic diodes will work), 1/2", press fit, 50amp (they come in positive, and negative)

After testing diodes with multimeter, if any are bad, desolder them, you press them out, press new one(s) in, and solder them back to the bridge. Sounds more complicated than it really is, its very easy.

Replacing voltage regulator was super simple, just remove and replace the same way.
 

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2002-2005 Range Rover MkIII / L322
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I love the rebuild it yourself approach. Since I was new to the water cooled Alternator, I found a reman on ebay for $185 and got a $60 core credit to boot!! So I was only out $125.
 

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Discussion Starter #5
Awesome deal Cartronics!

This is the diode test procedure. Diodes can only be individually tested, not when they are part of the bridge and linked with other diodes. Desolder, and press diode out.

Test resistance between diode post, and diode body (+ post, - body). Then reverse probes (- post, + body). You have to get a reading in one direction.

If there is a reading (any value as long as there is resistance) in one direction, diode is good.

If there is NO reading in either direction, diode is dead.
 
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