Alternator: Replacing Lees-Neville Alternator

By Brad 2002 U270 400 ISL

To remove the Lees-Neville alternator from a 2002 U270 400 ISL (130 Amp, by the way), one needs a bar to move the tensioner and take the belt off the alternator. Do disconnect the motor battery first…

Then you need a 15mm socket for the top bolt head, with an 18mm socket/wrench for the back nut. The lower bolt is 19mm. Once the alternator is removed, you see 4 wires. The two large outer wires are 1/2″ nuts and the two smaller ones (white sensing wire and ??) are 3/8″.Remember, white sensing wire goes closest to the motor. Reverse these two and the alternator will go to max voltage as it sees discharged batteries!

While some previous regulators had a pot on the outside, or a 3-position pot on the inside, the new one I got has a variable pot on the inside of the regulator (which is screwed onto the alternator). Clockwise increases the voltage output while counter-clockwise decreases. As was our case, I suspect these regulators are initially set to 14.5v when manufactured. Way too hot for our systems as that initial setting pumped out 15.1 volts when seeing very discharged batteries. It might be ok for flooded cells, but not AGM/Gels. So if you have this done, make sure you or the tech check the output. I learned that 15.1 volts will take 2 8G8D gels to 117 degrees F with less than 10 minutes of alternator charging. Trust me, I know this is true. Make them set it in the range of 13.8-14.0v. 

There are 4 screws holding the regulator in place. When you remove the regulator, the two brushes and springs with contacts will pop up. When you get ready to put on the new regulator, straighten out a heavy paperclip. There is a hole to insert it and then you can tuck the springs and contacts down under the pin. Put the new regulator in place and start all 4 screws. Holding downward pressure on the regulator, pull the paperclip out and finish tightening the screws. You’re done.

By the way, the shop charged me $111 for the new regulator ($42) and labor to completely disassemble and clean my dirty alternator as well as to test and re-test it. After discovering how hot it was set to (I did not think to tell him and the tech did not ask me what I wanted for voltage), I drove to the shop and pulled MH and toad into the alley. He tested it and then Rodney loaned me his tools to take the alternator off then and there. I did, he adjusted it to 13.8-14.0 and I put it back on.

Take whatever lessons you like from this. I certainly learned a lot and next time it won’t be traumatic. I am also going to be sure I carry some metric stuff with me and will have to go buy an 18mm as that is an odd size.