M1010 DUVAC Removal Plan "B"

Ok, it is not a direct boltup. The adjustment ear is about 1/2" too short, but nothing a simple homemade bracket couldn't fix. I haven't had a chance to do any readings on the voltage or amperage yet but hope to later tonight. It has put the factory dash gauge into the green for the first time since I bought the truck tho. The only thing I did different was to run the hot wire from the alternator directly to the positive accessory lug bolt on the front battery. I run hybrid deepcell/starter batteries that have a normal terminal and a threaded stud.

Btw, I vote we call this the Plan B Mod, since most of us 1010 owners have either tried or planned on trying different routes before finding this easy fix.

I took my M1010 on a weekend trip to the beach 2 weeks ago. this was the first trip with the new alternator set up. everything worked great. charged both batteries and had good 12 volt supply for my camper items. I would recommend this for others. the only modification I needed to do was some trimming to the alternator adjuster bracket to get full adjustment.

how much did the alternator cost? I was Considering putting a normal Cucv engine harness and alternators on my 1010 since I have everything for it.

I found the 12v Leece Neville listed between $200-250, the alternator I used is about $100-120 new. Check with local wrecking yards that deal with commercial trucks. You may be able to find a good used LN 12v since it seems they were fairly common on a lot of bigger trucks. I guarantee this will be a much easier and quicker way to go than to swap wiring harnesses and will have equal results. Wish I had known about this swap yrs ago, it's fixed the only real complaint I've ever had about my M1010. Thanks and kudos to M38inMaine for coming up with this mod!!

Is it possible to conduct this modification as a 12 volt conversion for the m1010?

Great to hear the conversions are working. I ordered the wrong size alternator the first time and it was too short as stated above. I sold it and bought the correct size to direct bolt in, part number is correct in my install post. So far mine is working great as well. I believe 160A is the minimum size you can get to get the correct size, just know that it's not cranking out 160A all the time, it only produces whats needed so don't get hung up on the large amp rating. As far as converting to 12v I believe that has been discussed in other posts, don't want to divert here and confuse people.

I would almost be tempted to just replace the two alternators with a pair of the 160 amp 12Vs and rewire the truck like a standard CUCV. Then you would have a predictable system, and full amperage available for the ambulance box... I can't find any reason not to do it that way.

Any other thoughts on that?

Crash_AF said:

I would almost be tempted to just replace the two alternators with a pair of the 160 amp 12Vs and rewire the truck like a standard CUCV. Then you would have a predictable system, and full amperage available for the ambulance box... I can't find any reason not to do it that way.

Any other thoughts on that?

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Joe, revisit post #11. It's even easier than rewiring like a standard CUCV. The ambulance ChevyC60 referred to is now mine. He installed 1 wire alts just like Mark did but added a second alt and just wired the lower alternator to the rear battery. It's brutally simple and works flawlessly.

Crash and and anyone else who might want to dig into the electrical system on these trucks I believe that this modification is how Chevrolet should have set all cucv's up to begin with it's the most straight forward and simple way it can be done. It is how all my cucv's will be setup from now on, one 12 volt and one 24 volt, I understand a lot of people want to go by the book but most civilian people that will want to help or need to work on them don't understand the normal cucv system, they do on the other hand understand two different systems like this and the non isolated alternators are much easier to find. This is my opinion and everyone has their on so have fun everybody it's just a hobby!

I am going to be doing this to my 1010 but I have a problem. my alternators are off and I dont know which wires are what. I took my engine harness completely out and eliminated the duvac wiring which narrowed my problem down to only two wires. I have two brown wires and I am not sure if both or only one is for the bottom alternator. One wire comes from where the harness plugs into the fuse box and the other wire come from a plug by the fuel filter on the fire wall. If some one can tell me which brown wire is what.

M38INMAINE PLANB Does it seem to still be working okay? I bought two new batteries and I don't want them to go bad, so i'm going to change mine to the 12 volt. M1010 TEMUDDY, MARIETTA, GEORGIA

Still going strong, drove her to work today in the snow storm!

temuddy said:

M38INMAINE PLANB Does it seem to still be working okay? I bought two new batteries and I don't want them to go bad, so i'm going to change mine to the 12 volt. M1010 TEMUDDY, MARIETTA, GEORGIA

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If you refer to post 11, that truck mentioned is now mine. Not one single issue since the update. Super easy.

still working for me also. nice and simple

Still working for me, even though I started loosing antifreeze out of the passenger side exhaust of the truck....think I popped a head gasket

Great info here guys.
I just acquired an M1010 myself and am going to get this Mod done to see if it helps cure her charging ailment. Will one of the standard CUCV alternators work? The 12V 100amp that looks like this:

http://d3d71ba2asa5oz.cloudfront.net/32001220/images/9185691-wm.jpg

I ask because I have two of these alts, with the complete original wiring harness. It would be nice to be able to use one of these so I don't have to drop the $$ on a new alt. That $$ could go towards other mods!

Thanks in advance guys.

While the mounting system is referred to similarly (J mount I think) the 27SI has a smaller frame.

They will not work as a direct bolt in, you need the one I list at the beginning. I found mine on ebay for much cheaper.

Just to double check, the 2ga. cable from the new alternator will go to the front battery positive? or the back battery positive? The original pics from the OP appear to have it going to the positive on the rear battery, but isn't the front battery the 12volt part? Just wanted to clarify. Thanks.