Bosch part numbers 2002 alternator (stator and rotor)

[D.martijn]

Hello guys,

 

I started gathering some new parts so I can rebuild my alternator, I already disassembled it completely and as suspected the stator is burned.

Since then I started looking after a replacement stator via the diagrams on Realoem and using the BMW part no on the Bosch catalogue to get the Bosch part no.

I have a 0 120 400 752 (45A) Bosch alternator. 

 

Bosch numbers via BMW part no:

Rotor: 1 124 034 016 (or 1 124 034 380)

Stator: 1 125 045 010 (or 1 124 229 025)

If I search for this rotor some sites state that this is a 35A?

 

I also contacted Bosch and they send me a diagram (see attached pdf) with all the spare parts for my alternator but it the numbers are different.?

Rotor: 1 124 034 381 (Same site as the other rotor says this is 45A)

Stator: 1 125 045 026

If I now put those Bosch numbers in Realoem they tell me that it's for a 2.5CS-3.0CSL and 2500-3.3Li...

 

Already bought a NOS 1 124 229 025 stator on Ebay for only 3€ (I was the only one bidding) +10€ shipping which is pretty cheap as these seem to go for 50-80€.
I Would also like to buy a new rotor for my alternator as it's pretty rusty and has quite a bit of wear on the commutator.

 

I'm now questioning if I should stick with the Bosch numbers from BMW or the numbers that the guy from Bosch gave me.?

Hoping this is somewhat clear?

 

New Bosch stator (Same OD, thickness, windings as the old one)

 

Old one

 

Alternator number

0 120 400 752.pdf

[D.martijn]

No one here every rebuilt their alternator before..?

[Simeon]

Bosch will have used those parts on more than just BMW alternators so I would stick with their numbers as you may benefit from a wider range of sources. 

 

The rotor and the commutator rings can just be cleaned up by turning down the unworn sections in a lathe. If everything checks out electrically in terms of winding resistance and insulation then no need to replace. Generally all of the wound components are in good condition and refurbishment really means new bearings. 

 

Have you checked all of the diodes? I was told that the triple diode pack contained in the body casting is now unavailable. 

[D.martijn]

Yes, but if I can find a new rotor cheap enough, why go through the hassle of cleaning/resurfacing the rotor?

I went to my local electric refurbishment center and they told me they solder/apply new cupper/silver on the commutator but it's almost the same price as a new rotor.

 

You can still get the separate diode assembly (1 121 099 007) but not the one that's in the body itself. Although the same guy here locally told he these never seem to go bad. I'll still try to measure these out though.

 

I've since yesterday found a Bosch rotor in Germany with the number the guy from Bosch gave me so I might pick that one up.

And yes I do understand that they will have used those parts on other alternators too but when I search the for the stator number that he gave me I can't find it back on their online catalogue, so how does one know it that is the right number/that stator actually exists... 

[TobyB]

Quote

No one here ever rebuilt their alternator before..?

 

I can say honestly that I never have.  I've stuck new brushes in once or twice, when in a bind,

but the stock charging system on this car's marginal enough, and an E21 alternator cheap enough,

that whenever they poop out, I look upon it as an opportunity for advancement, and upgrade.

 

I've had more trouble with regulators and wiring than I have with the alternators.  Although the stock

alternator does sometimes tend to machine itself apart on a race motor...

 

t