PIcs of a Tdi alternator rebuild

**Utemad** · 21st March 2007, 06:07 PM

This is a good thread

I have bearing noise in my alternator and since I was having a bad day at work I thought I'd pull it apart and see if I could replace the bearings. Although I probably should have read this thread first

I managed to get the alternator out and then remove the plastic cover and the regulator. Nothing like needing 573984729874 different sized tiny spanners and sockets to do a job. Then I unsoldered the tabs using a gas soldering iron as a blowtorch and a pair of pointy nosed pliers. Got the back half of the case out okay but needed to put the pully in a vice between two lumps of wood to get the pulley off to get at the front bearing. Then tapped out the back bearing.

So now I have an alternator in bits with one removed bearing and another bearing still on its shaft. So off I go to find an appropriate bearing puller. Hmmmmmmmmm don't have one. Okay I'll just look in the bearing box for some bearings as they look pretty common. Hmmmmmmm don't have any. Okay then at least I'll have some heatsink compound in the toolbox. Hmmmmmmmmm no I don't.

So I guess it is off to Gympie in the morning to get all the bits required to finish the job. Lucky I can use the company ute otherwise it would be a looooong walk.

If I'd read this post beforehand I could have had the bits on hand

The two bearings in my alternator had the following part numbers on them.
6303RDD (front)
6003DW (rear)

This is for a 1994 3.9L V8 Disco with serpentine belt.

**MacMan** · 21st March 2007, 09:35 PM

The 6000 series bearings are common enough, but I'd make some calls first.

Or sacrifice the lot to the gods and put in a Bosch!

**Utemad** · 22nd March 2007, 09:08 PM

Ok I have replaced the alternator bearings and did the adjuster pulley bearing at the same time.
The original post mentions that a 3in puller is the max size to do the job. Which is just as well because I couldn't find anything smaller for sale in Gympie. As it is only Autobarn of all places had one. However I did have to modify the puller to get in behind the bearing as the bearing is hard up against something else and you can only just grab the outer part of the bearing. I just ground the hook part of the puller on both legs on the bench grinder until it would grab the bearing. No biggy but wouldn't have wanted to do that to an expensive puller as I ground out a fair bit of metal.

All in all a pretty easy job if you had everything on hand. Only $13 all up for the three bearings.

**MacMan** · 23rd March 2007, 09:33 AM

Even with a modified puller, you're taking far more care than the average auto eletrician would. I've seen them just jam two narrow tipped 18" pry bars in either side of the small gap between the bearing and the rotor body, and throw their entire body weight behind it. I guess it works, and you're throwing away the rooted bearing anyhow!

**Utemad** · 23rd March 2007, 09:53 AM

Originally Posted by MacMan

Even with a modified puller, you're taking far more care than the average auto eletrician would. I've seen them just jam two narrow tipped 18" pry bars in either side of the small gap between the bearing and the rotor body, and throw their entire body weight behind it. I guess it works, and you're throwing away the rooted bearing anyhow!

I looked at doing that but it is the thing you would be levering off that I reckon would cop the damage.

**DarrenR** · 24th March 2007, 12:49 PM

Originally Posted by rick130

Bear in mind this is a Disco Tdi alternator, the Deafener Tdi Magneti Marelli (Lucas) 65a one is different. It posess that piddly little INA needle roller behind the commutator that should be removed every so often, cleaned out and re-greased.

Just slightly on topic, the Magneti Marelli 65a, is this the norm for a defender & Disco? the LR workshop manual say 65, 85 (i think) or 100a. My 97 Disco D1 has a 100a, anyone have a 100a?

Is the Magneti Marelli really a Lucus ???? what a pity, its bound to fail then as it's a built in feature of all Lucas crap.

Good howto on the Alternator rebuild Langy.

Best regards
DarrenR

**langy** · 24th March 2007, 04:08 PM

Around the mid 90's, different model 300Tdi's were supplied with slightly different alternators. 300Tdi defenders ended up with 65amp alternators, as said before, a MM built version of the Lucas -Disco's got the 100amp version straight off , and defenders caught up later.

**DarrenR** · 24th March 2007, 05:42 PM

Ah I see thanks for the info Langy.

Best regards
DarrenR

**Utemad** · 24th March 2007, 07:18 PM

My 1994 V8 has a 100 amp MM.

I wrote the numbers from its ID sticker down before I reinstalled it. As the sticker is on the bottom and can't be seen when installed.
The only number I didn't get in full was th epart number as it was damaged.

Thread: PIcs of a Tdi alternator rebuild

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