ALTERNATOR Overhaul

[jp928]

A little while ago a mate had a failure on his Subaru alternator (replaced it), and gave me the old one to play with. These Mitsubishi units are not regarded as fixable here, so I pulled it down and fixed - $40. Lately I got an NA6 alternator (model A5T03677), also Mitsu, but smaller, so I thought I will see if that would come apart the same way. Even easier, but there is a trick. After removing the front pulley nut and undo the 4 bolts holding the front and rear halves together (mark halves so they go back together the same way), the front cover should tap off the shaft OK, but the rotor wont come out. Also remove the output cable connection and its plastic connecting stuff so there is only a threaded spike sticking out backwards.
There is a bearing in the rear case that will only come out with the rotor after you heat the centre of the rear case - just too hot to hold your hand on, but can easily hold with a cloth or leather glove. May take a bit of persuasion, or levering at the back of the rotor through the cooling holes in the rear case.
Now you will see three flat headed philips screws - undo these and the stator ( cylindrical bit with heavy wire windings front back) will come out attached to the brush carrier and regulator. On the Subaru version there is a 4th screw that is only accessible by carefully moving the stator to one side by bending the wires that connect it to the brush/regulator assembly so you can reach the screw from the side.
The 4 screws holding the front case bearing in can a bit hard to loosen, so be prepared to persaude them out. Once out remove the retaining plate, heat the case up and the bearing should fall out.
This video shows how to dismantle the rear assembly to change the brushes, although I dont recommend using a plumbing soldering iron here. Also shows how to hold the brushes back to allow the rotor to be fitted past them.
https://www.youtube.com/watch?v=qOo0iSnmwP4

The front bearing is easy to source (6303 in this case, can be had for $9), but the rear will probably have to be ordered in, as its not common. All up $20-25. If there are no signs of rough bearings, leave the rear bearing alone, but the front one takes the heavy loads and its cheap and easy so I would do that one at least.
Did not know how many kms were on this unit, but the slip rings (where the brushes rub) wear was visible but barel detectable with a finger nail.
Brushes are the problem here - nobody stocks them (or admits to it) in Oz. I found two sources eventually - one in UK at JCR Supplies (MITSUBISHI ALTERNATOR BRUSHES FITTED TO FORD TRANSIT 5MM X8MM X23MM REF 140817)- complete brushes with springs and plates - A$21.80 posted; other at Canterbury Auto Electric Service (NZ), sales@caesltd.com - cheaper but lack spring and cap(transfer from old brushes), and they wont post to Oz readily.
Once you have the stator and rear assembly back in place, screw all tight, push the brushes fully back and hold with a wire through the hole in the back, and dont forget to heat the rear case again before trying to fit the rotor. Heat the front case to allow a new bearing to drop in, and fit the plate, and assemble the front cover to the rest.
Beats the hell out of $300-400 for a replacement unit.

hth somebody.
jp 92 na6 96 na8 turbo in a clubbie

[93_Clubman]

Useful to know.

[jp928]

Small update . If your brushes are different from those above (5x8x23mm), you should be able to locate their size and/or part no by searching on the alternator code -eg A5T03677, or A3Tnnnn , whatever is on the id sticker on the body. The brushes above are listed to fit many models , so I dont think there will be too many brush variation. I suspect the model variations relate to external fittings like the type of pulley, current rating, mounting lugs etc.

jp 92 NA6, 96 NA8 with turbo in a clubbie