How I Replaced the Alternator on our '99 Montana

10-17-2015, 01:15 PM
I bought a new 125 Amp Alternator for the Montana a few weeks ago. Great deal, came all the way from Georgia in about three days. Bought it off Amazon from a company called and I have purchased from them before with the same fine results. Even RockAuto can't ship that fast, or match the price.

Anyway, I researched the various methods for creating enough space to remove the alternator over the top of the engine. I decided that dropping the sub frame was the easiest way to go. I blocked the sub frame so it couldn't fall more than 4 or 5 inches on the passenger side with an axle stand, removed the wiper arm rod from the mechanism, motor mounts from the rad cradle to the top of the engine and tied the engine off with 2000 lb nylon rope to keep it rolled forward.

That gave me just enough room to reach back to loosen the two back bolts with a 3/8 drive, a short extension, a universal and 13mm or 15mm shallow 6-point socket (not sure now if it was 13mm or 15mm but whatever the one out front the holds the alternator bracket on is, is the same size).

So far so good. Came out nice, no bending wiper motor bracket or other 'stupid' stuff.

Going back together should have been a snap, but the blind nut in the rear part of the sub frame had broken loose - welds broke, when I pulled the bolt out and I had to cut the boxed part of the frame near the floor so I could get my hand in behind to hold the nut (welded to a trapezoid plate) while I started the bolt.

Because of this small 'wrinkle' it took a little longer to remove and replace everything, but all in all it was a reasonably easy thing to do. There are some other important steps, including disconnecting the battery before you remove anything but that should go without saying.

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