Alternator Repair AL0734X
 

Hi,

The 2003 X5 4.4l has the Bosch alternator
A water cooled wonder on engineering.

But they do go faulty at times, and the one in my car has been showing signs of doing so.

So I decided to find the parts and rebuild the unit, after it cant be that difficult.

Some photos
 

First of all,

It was an easy job after all.

The parts where easy to find
The regulator cost about 26 Dollars. Bosch number IB200
The bearings are a 6203 and B17-99D (17x52x17)

The bearing where not needed after all as they where still fine

One thing I did learn
It is not a good idea to split the top casing from the bottom
This rips out the wires from the Diode blocks
But us easily fixed,
I soldered them back again

Steps to follow
 

So the first step is to remove the pulley
Then take the four bolts out and the one nut on the positive terminal

This allows the black cover to be popped off, the silicone was old and so it popped off quiet easily

Remove the old regulator by taking out the four Torx holding it down
Replace with new regulator
Fasten the four Torx
Put the cover back with new silicone

Tighten the four bolts and add pulley,

All done

So I cant see why a recon unit can cost so much

If the do the bearings, then the casing needs to be split,
And the it is easy to get to the bearings,
But if you do this, then loosen the wires from the field before you split the casing, and solder them back once done

Interesting desing
 

The alternator seems to have an induced field to activate the rotor

With this the unit does not need brushes, and so one less wear part

Brilliant design

If you do split the casing you need to add heat transfer paste between the front casing and the back, this allows the heat from the regulator to be transferred to the back where the water is

This step is not needed if the bearings are fine

The front bearing is a double race unit and will take a while to fail

So now it is fixed
 

The total cost in parts was the regulator at about 26 dollars from a Bosch dealer

Item IB200

The time whit splitting the casing probably an hour, but if only the regulator is changed then only about half an hour

The battery voltage is now about 14 VDC when revved
and 13.6 on idle

And a lot easier than I thought
I searched the web to see how it is done and found nothing

So I hope this helps