1968 MF 135 diesel wiring

[Whistlin10Speed]

Whichever is easier I’ll put it that way. The gauges look like they have some water inside them, I’ll probably replace them since they already don’t work

 

[Jim.ME]

Replacing in kind will likely be easier for you at this point. If the fuel gauge works you may not want to change it, as the gauge and sender ohm ranges need to match. Also if the fuel gauge doesn't work the problem could be a bad sender. I would get it rewired, see what works and what doesn't and do some checking, before just replacing all the gauges.

 

[m16ty]

He will want to do more than that if he has lights, like add a fuse or breaker (or two), to use as terminal points to avoid over loading the oil pressure switch. The alternator wire has to go to the battery post of the solenoid. Removing the ammeter removed power from the oil pressure switch, which will need to be repowered.

I always like to add an exciter circuit to the one wire alternators, as some of these old tractors don't turn enough rpms to reliably excite the alternator.

 

[Whistlin10Speed]

I always like to add an exciter circuit to the one wire alternators, as some of these old tractors don't turn enough rpms to reliably excite the alternator.

I feel like an idiot trying to figure all this out lol. Seems simple but the one wire alternator seems to throw off the diagram in the manual. I know the other fella made an updated one for me so I will try to blow it up on my computer and compare but jeez, I figured there would be a harness I could buy and throw on and be done with it.

 

[Jim.ME]

I always like to add an exciter circuit to the one wire alternators, as some of these old tractors don't turn enough rpms to reliably excite the alternator.

My understanding is that not all one wire alternators will accept an excitation wire. Why not just use a 3-wire alternator, readily available at any parts store, if you are going run an excitation circuit. It only needs a 4-inch jumper from the sensing terminal of the alternator to the battery output terminal to finish up.

More important is to use a small diameter pulley of the correct width for the OEM belt.

 

[Jim.ME]

I feel like an idiot trying to figure all this out lol. Seems simple but the one wire alternator seems to throw off the diagram in the manual. I know the other fella made an updated one for me so I will try to blow it up on my computer and compare but jeez, I figured there would be a harness I could buy and throw on and be done with it.

Someone may make a harness just like you need. You need to research and contact vendors to figure it out just what is available. In less time than you will spend researching you can have your tractor rewired.

The picture below is the diesel diagram enlarged. I got it clearer than the one I modified. Try comparing this with the modified one. The modified one ha the original alternator wiring and regulator removed. There are a few connection changes required because of that removal. You can do this; it is not as bad as you think. If I get some time, I will try modifying this one for you, however I think you will see the changes if you print both out to compare this one and the modified one side by side. Follow the lines, the writing was not changed on the one I modified.

 

[Jim.ME]

Try this one.

 

[Whistlin10Speed]

Try this one.

View attachment 116932

Can’t read it on my phone, I’ll try my laptop this evening.

 

[Whistlin10Speed]

I can read it much better on my laptop. As far as getting the wire, do I need to just get 4' of each color and then custom cut it and install terminals?

 

[Jim.ME]

I can read it much better on my laptop. As far as getting the wire, do I need to just get 4' of each color and then custom cut it and install terminals?

4 feet might be a bit short for some. I would say see if you can get the 10-to-20-foot bubble packs. I never paid much attention to actual length of each color; I buy the 100-foot rolls of 14 gauge. The 10 and 12 gauge in 10 to 20 packs other than red and black which are 100-foot rolls.

Yes, you cut it to the length you need and crimp the required terminals on to match the connection points.

 

[Whistlin10Speed]

Ok thanks. Do I need to do copper or is it ok to use aluminum/ silicon?

 

[Jim.ME]

Ok thanks. Do I need to do copper or is it ok to use aluminum/ silicon?

Stranded, copper automotive wire

 

[m16ty]

4 feet might be a bit short for some. I would say see if you can get the 10-to-20-foot bubble packs. I never paid much attention to actual length of each color; I buy the 100-foot rolls of 14 gauge. The 10 and 12 gauge in 10 to 20 packs other than red and black which are 100-foot rolls.

Yes, you cut it to the length you need and crimp the required terminals on to match the connection points.

I personally usually don’t buy anything but black and white, and maybe some red in the place of black. I will just number each end with quality numbers that won’t fall off. I buy it by the roll and don’t want to stock enough rolls to cover every possible color.

 

[Jim.ME]

I personally usually don’t buy anything but black and white, and maybe some red in the place of black. I will just number each end with quality numbers that won’t fall off. I buy it by the roll and don’t want to stock enough rolls to cover every possible color.

As you say using colors is a personal choice. I do enough that I feel it makes sense to have at least the common gauges and colors used for standard trailer wiring (7 wires), so I have different gauges and colors to use if I make a tractor or other harness. To me it is helpful to be consistent with original colors as much as possible when repairs are made or a rewire is done. If problems arise, I know which wire I am chasing easier than sorting through a bundle of black wires, saving time. I do have numbers around as well as some narrow, colored tape to use for identification marking if needed. I try to make it a point to put a sketch or description in the manual for a tractor I rewire so I know what I did if a problem arises in the future or I need to add a circuit.

 

[Whistlin10Speed]

Ok thanks. Do I need to do copper or is it ok to use aluminum/ silicon?

 

[Jim.ME]

Ok thanks. Do I need to do copper or is it ok to use aluminum/ silicon?

As far as I am concerned you want stranded, copper automotive wire, as I posted for you when you asked this before (post 52).

 

[Whistlin10Speed]

I may have already asked this and I apologize if I did. Would it be easier to just get the correct alternator and then buy a premade harness? Also do you know what Lucas electrical is? I’ve seen that on many of the harnesses that are available premade.

 

[Jim.ME]

I may have already asked this and I apologize if I did. Would it be easier to just get the correct alternator and then buy a premade harness? Also do you know what Lucas electrical is? I’ve seen that on many of the harnesses that are available premade.

Lucas is a UK electrical component manufacturer, like Delco Remy was in North America. The Lucas harnesses you see would be for the 135s made in Great Britian. Those 135s used Lucas starting and charging systems as well as smaller components. The harness won't fit your US made 135, without modifications. Lucas systems seem to be known for problems. That would not seem like a good option for you.

Can you read the last diagram I reworked for you? Do you understand it? That is a fairly simple diagram and to me would be less work to wire the tractor with that diagram than trying to sort out a Lucas harness to work on your tractor. The Lucas harness will not work with the original Delco10DN alternator and regulator unless significant modifications are made to it.

The one-wire Delco type alternator you have is about as simple as it gets. To go back to the original alternator, you also need the external regulator to go with it, and more wires are required to make them work.

Start by making a copy of the drawing I did and white out everything to do with the lights for now, you will be looking at a good bit less wiring to figure out to make the tractor start, run and charge. Get that much wired, then do the lights by themselves.

 

[Whistlin10Speed]

Yes the diagram you sent shows up significantly more clear now and I have read over it. After looking at the tractor I think that’s my best bet, it makes a lot more sense looking at the tractor than just me thinking about it. Sorry again for the frustration, as I mentioned this is not my specialty.

Do you know my tractor is made in the US by the serial number?

 

[Jim.ME]

Yes the diagram you sent shows up significantly more clear now and I have read over it. After looking at the tractor I think that’s my best bet, it makes a lot more sense looking at the tractor than just me thinking about it. Sorry again for the frustration, as I mentioned this is not my specialty.

Do you know my tractor is made in the US by the serial number?

Are the headlights stud mounted on the sides (US built) or in the grill (Great Britian)? The GRB built ones had a different serial number format and did not use the 9A prefix before the serial number, I believe. Does the serial number tag say Made in the USA , or some other country?

Don't bring yourself to a stop thinking about it (aka paralysis by analysis). Get some wire, terminals, tape, etc., get out there and have at it.