Farmall MD ???'s

First off, I cant seem to find anywhere in the book as to if my MD is 12V positive ground or negative??? Secondly, what are you guys running for batteries in yours? Trying to find the biggest battery I can that will fit in the battery box. Pulled the 875CCA out of my SM and it worked pretty good on the MD so would like something that big or even bigger if I can find it. Local auto store sells Deka and I have had good luck with those but the biggest he can get that will fit in the box is a 770CCA...
 
The MD was positive ground and used two 6 volt batteries, one in the usual battery box under the gas tank, one beside the seat. Positive terminal of one under gas tank connected to negative terminal of one by seat. Positive terminal of seat grounded, negative terminal under gas tank to starter switch. I do not know the cranking amps.
 
Originals used two 6 volt wired in series for a 12 volt positive ground system. Most all have just used one 12 volt battery for years. Good battery and good heavy battery cables would be good. Thats original, can't say what you have now without more information or seeing tractor.
 
I agree and would like to add: Unless it has an alternator you can make it either one by polarizing the VR to your preference. I would stick with neg ground bc people tend to get confused with pos ground. Then BE SURE TO WRITE IT ON THE UNDERSIDE OF THE BAT BOX LID so if somebody other than you is playing with it they know what is going on.
 
By the way since you two are the most knowledgable people I have ever seen on the bat box beside the seat, how does it mount up? Was it the same box as under the tank, but with a different little bracket? I think I still have the bracket on my tractor and I would like to at least put a dummy box there and use it for tools. I could hook the two 12 volts in parallel and really have some CCAs!
 
Yeah I see in the manual is originall had two 6V batteries. Probably going to just stick with the biggest single 12V I can fit. Not sure how my VR is currently polarized. Should I just replace it or can I repolarize it?

Also, looking at some other parts; will a starting carb off a WD9 fit an MD? Dont really need the carb but need the drip trough off it and thought an extra on hand might be nice. THanks!
 
Matt, All IH gas start diesels came from the factory as 12 volt positive ground. I have an MD, 450-D and 650-D. Any good 12-volt battery seems to work fine. I just get $20 used batteries from a local service station and they work very well and last for years. These diesels start easy on gas and don't seem to need high cranking amp batteries. But I don't start mine in cold weather which might require a large battery. Al
 
Boxes were made different on bottom and the lids mounted different. There was 2 different ones, I think the later mounting change was made when the seat with spring under it was starting to be offered. Last time I saw a beside the seat box was at a red power round up years ago. If I remember correct Justin Weber Had 2 NOS ones. I know he had at least one, because I was thinking about buying it for a MD I had at the time. Pretty sure I looked at two though. Also IH made parts to change the side box mounting to clear hydraulic hoses when a remote control hydraulic attachment was used. Sorry can't remember any exact details about the boxes.
 
(quoted from post at 17:27:50 09/12/10) Yeah I see in the manual is originall had two 6V batteries. Probably going to just stick with the biggest single 12V I can fit. Not sure how my VR is currently polarized. Should I just replace it or can I repolarize it?

Also, looking at some other parts; will a starting carb off a WD9 fit an MD? Dont really need the carb but need the drip trough off it and thought an extra on hand might be nice. THanks!

Retry:
Yes, you can repolarize as much as you like.
Carbs are the same.
Drip trough is not necessary to run the tractor. Just keeps gas from draining onto dist cap when draining carb.
OEM sells the drip trough for $30.
 
Just saw the wanted photo ad. If thats a picture of the tractor in question a altenator was added sometime. It probably needs to be negitive ground.
 
(quoted from post at 03:06:46 09/13/10) Just saw the wanted photo ad. If thats a picture of the tractor in question a altenator was added sometime. It probably needs to be negitive ground.

Yes sir, that is definatly an alternator. That was part of my theory in saying to make it neg ground even though it isn't original. You will never be wrong alt or gen that way.
 

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