Reinstalling alternator on M110 W460 engine

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nz280ge's picture
Joined: 03.02.2013

Something as simple as replacing an alternator is easy in theory, a bit harder when doing it on your own, on the ground, with no one to help. Here is how:

Tips on removal. Buy a label maker and label the three alternator wires. I labeled them left, middle, right.
Degrease everything so your hands stay cleanish and crud does not drop in your eyes.

If you live in New Zealand, send or take the alternator to Jacob at Electro Charge (ElectroCharge) in Auckland. I came over on the car ferry and asked while I waited if he could break it apart to tell me if it was salvageable or if the bearings had spun in the housing. He asked if I could do some shopping for an hour, and when I returned, he had repaired it. He showed me the smaller bearing was the source of the squeal, and he replaced both bearings and brushes for NZD $80 all up, including labour and GST (sales tax). He also said the regulator was allowing too high voltage, and he would order and send me one. Looking at his google reputation, everyone seems to feel the same about his work. Brilliant and fair prices

Putting the alternator back in is difficult because it is deep down. The secret is a sharpie plastic pen to align the under-alternator bolt spacer.

  1. Install the top bolt in the housing. Easy
  2. Pull the belt back on. Medium hard... pry bars, screw drivers, lot's of cursing
  3. Use a mirror and flashlight to understand the location of the lower bolt hole (working blind)
  4. With extra wedges to hold it in place, try to get the lower bolt to go into the housing and the first bit of the alternator. Hard because of access. You can't see what you are doing and because you also have washers to deal with. Lot's more cursing.
  5. When you have got it in, grab a sharpie pen, get under the car, hold the bolt spacer roughly in place and use the back end of the sharpie to hold it in place. Otherwise, if you are a one-man shop and don't have a lift, it will be almost impossible to get it to stay in place to get the bolt through.
  6. With a lot of mirror checking, you should get it aligned.
  7. When you do, from the top, press the lower bolt in through the alternator spacer until it hits the sharpie.
  8. Remove the sharpie from underneath the car
  9. Jiggle the lower bolt from the top until it comes out the other side of the bracket
  10. Slightly tighten both top and bottom, enough so you can move and tension,
  11. Get some heavy trucker straps (black rubber ones), use a lever to tension the fan belt and use the straps to hold it in place
  12. It is easier to do if you have a side air ratchet to tighten the bolts. Tighten the top and bottom bolts
  13. Install the three alternator wires
  14. Hook up the battery (you did remember to do that before removal, right?)


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Jdring's picture
Joined: 12.04.2004
Location: South of Oxford, UK. 87' 230GE SWB Manual, 89' 230GE SWB Auto, 2012 G350Bluetec LWB
GWOA Groups: Committee, Members
Re: Reinstalling alternator on M110 W460 engine

Thanks for taking the time to document.

Everyone needs a Sharpie in their toolbox.

I've done this a couple of times and it wasn't that hard, tbh.  Access is admittedly stupid for such a large engine bay.  I now have a 350 Cdi and I wouldn't attempt it there - just too much other stuff around and I'd be caught without the right tool for sure.

Nick123's picture
Joined: 12.01.2004
Location: Argyll, Scotland
GWOA Groups: Members
Re: Reinstalling alternator on M110 W460 engine
Great write up. Thank you.