"<font color="#6699ff">[b:654c4848f0][i:654c4848f0]the ammeter needle is far from steady[/i:654c4848f0][/b:654c4848f0]</font>"
Had the same problem with a new ammeter gauge that "bounced" radically on our 52A.
The gauge eventually failed and was replaced with another new ammeter gauge.
"<font color="#6699ff">[b:654c4848f0][i:654c4848f0]Should I be thinking worn gen brushes[/i:654c4848f0][/b:654c4848f0]</font>"
You might consider polarizing the generator.
Polarization is a procedure which matches the polarity for the generator and the voltage regulator by permitting a surge of current to flow through the generator, correctly polarizing it.
Damage to electrical components can occur if polarities do not match.
Polarization of the generator should take place whenever any of the following events occur:
1. The battery is replaced or disconnected from the tractor
2. The generator is replaced or serviced
3. The regulator is replaced or serviced
If any of these events occurred, do not start the engine until polarization is done. The polarity of the generator must be set to match that of the voltage regulator.
Make a jumper wire (14 or 16 gauge) and put alligator clips on both ends.
Polarize the generator by using the jumper wire and momentarily jumping from the BAT terminal on voltage regulator over to the ARM terminal on the generator to get a small spark.
"<font color="#6699ff">[b:654c4848f0][i:654c4848f0]or a poor ground in the wiring?[/i:654c4848f0][/b:654c4848f0]</font>"
Take a look at the diagram below.
Check the white wire and connections at the [b:654c4848f0]BAT[/b:654c4848f0] terminal on the voltage regulator and ammeter post.
Check the voltage regulator lead to the [b:654c4848f0]F[/b:654c4848f0] terminal on the generator.
Check the voltage regulator lead to the [b:654c4848f0]A[/b:654c4848f0] terminal on the generator.
Hope this helps.