The half shafts need supporting during this time otherwise the gaiters will wear out due to friction caused by the shaft angle if they are allowed to drop.
So the commutator cleaning worked and at the same time I changed one of the 4 brushes to graphite roughly cut on a band saw.
After 2 weeks I looked at the commutator and brushes again to my dismay the commutator had started to burn out again and the 3 carbon brushes had worn right down.
The 4th graphite brush had NO WEAR at all. I decided to replace all carbon brushes with GRAPHITE.
This time I cleaned up the commutator with 120 grit emery paper on a wooden stick which I rammed in between the brush holders. This cleaned up the commutator burns in about 60 seconds! (about 10kg force)
The new graphite brushes were made a loose fit in the holders.
There have been no motor problems since doing this.
Conclusion the carbon brushes were polishing the commutator and causing arcing which wore away the brush and oxidised the commutator. The soft graphite is a much better thermal and electrical conductor.
Other things of note: Battery charging: ignore battery water level light (do not reset it EVER) top up water in all 5 packs every 2500 miles immediately after end of charge. Catch overflow electrolyte. You can see the general health of each battery pack from the colour of the overflow Dark yellow = sick straw coloured = normal. Also check SG of the overflow normally its about 1.1
I had a problem with the charger overheating if the van was recharged immediately after a long drive in hot weather. This was fixed by fitting a 70mm DC fan above the charger module inside the cover, this rapidly recirculates air around the inside of the casing and prevents hot spots without allowing dirty air in.
