Well, after the plastic has been removed from the backside, remove all the screws, used a 1/4 set for all. Vreg lifts off and youre left with the bridge.
Here is my old corroded rectifier, you can see where the field windings have been soldered. You need a powerful soldering iron or as I did, a small blowtorch/jet lighter. Heat it up and open the the tabs with knife/screwdriver and free the windings, then you can lift the bridge off. Clean the windings from excess solder so they fit trough the casing (if it has never been repaired, it might not have solder so you can just pry them open).
Now you need to test that the field winding are not shorted to the housing or rotor. Multimeter on ohms range should not show anything between them and the case. Measure the that the wires are not burnt out, should be almost short circuit between the phases.
Check the rotor coil too, the resistance is higher on that.
Now you know the alternator is good for repair.
Remove the nuts for the housing and you could try prying it open with knives/screwdrivers or an axe. Failing at that, grip on the other half of the alternator (slipring end) with something, put stuff trough the ventilation holes if necessary, dont use too much force or the rotor will touch the stator as the case deforms. Tap on the slipring end of the rotor and it should start coming apart, tap on the joint between halves if the look corroded to free them. Watch the wires.
If the slipring end bearing was left on the case, just tap it off, otherwise you need a puller.
Pulley off and hit the rotor off the case and remove the bearing.
Replacing the slipring, is it too worn? 1 or 2mm gone isnt too much and it should still be usable for quite a while. The slipring has two similar clamps as on the rectifier, might not have solder on them at all, if it has no solder and you are not going to replace the slipring, resolder the joints, open them up and you see the wire is almost gone (as in my case only 1/3 of the original diameter, you can take extre wire if necessary from where the coil attaches, scrape it clean and solder).
Break the old one and take it off, clean, put some oil on the shaft and tap the new ring inplace and solder it.
I used dremel with wirebrush to clean the casings where they join, meet the engine, and where the diode bridge sits on.
Install new bearings 6303 2RS C3 and 6003 2RS C3, pulley end to the casing and then put the rotor on (use pipe or similar when tapping the rotor down to not damage the new bearing.
Install the slipring end bearing on the rotor and put the other half on, watch the wires, and tap it on, make sure the plastic sleeve is right.
Then its pretty straightforward reassembly, solder new brushes to the Vreg if necessary
This for the A127I (should apply to A115 too, not sure about bearings), but alternators arent that much different from another.
