Geoff Weeks

Yeah,I saw the spring and thought "what the heck is going on here" but don't know Macks all that well, and don't claim to have seen everything so didn't say anything.

This ad lists a bunch of interchange part numbers which may help in your search: https://kuwait.whizzcart.com/product/19384513/new-diode-trio-compatible-with-1a-leece-neville-79021-33-500-l79027-l79027hd-505202-l79027hd-1-33-500-1-l79027-1-171-16000/ I looked up 79021 and 79027 on my search.

Diode trio and connection marked in black https://www.ebay.com/itm/302551471197

Ok, that is good news, You do have power to the alternator, so a wiring fault between it and the batteries is unlikely. In North America these are referred to as "one wire" type alternators, A bit of misnomer on the L/N because the case isn't the "ground" for the alternator. They "turn on" by residual magnetizem in the rotor producing a small amount of current in the stator, which runs through a separate set of diodes (diode trio) and is fed back into the field (rotor) regulator to turn it on. The regulator also is connected to the main output studs internally so when it turns on can supply battery to the field. The little wire between the two big wires is the feed from the diode trio to the regulator, to tell it to turn on. If your electrical guy doesn't know this, he may have supplied external power to that wire and the regulator turned on and worked. If that is the case the diode trio is the problem. It is the white piece that is connected to the three small studs and has the wire coming out of it to the little ring terminal up by the regulator. That trio is replaceable I am assuming (never a great thing) that he knows how to test the output current and main rectifiers when he did get to to charge on the bench. So assuming that is true it looks like you need a diode trio.

Test light will work fine, for seeing if he has power to the output terminals! There should be power there all the time, even with the engine stopped or the key off.

Spoke hubs are part of the axle/brake combo. They are generally sized by the axle weight rating and the axle shaft design. So a hub on a DS402 the hub must fit the axle housing and the axle flange. The hub bearing size and placement is determined by the axle mfg. I used spoke hubs from a Volvo with a DS 402 on my Marmon with DS and later DT402's

If the light doesn't light across the two big terminals with the engine stopped, then you have a wiring problem. There should be 12 volts across the two big terminals at all times. I can see the - goes right to the block, trace the +

Front brakes were optional on TRACTORS, at one time, I believe straight trucks need front brakes regardless of year. Edit, my bad, I thought this was the firetruck thread.

Yes, I have it. May be a day or two before I get it to the post office. I am knee deep in a few projects.

What I got: some defects in the chrome top (bubbles but still in one piece) IHC part number but looks similar. same deal as the speedo, you pay shipping and it is yours for free.

I have no idea on Mack if it is normal, I was just saying it can be. In any position does the non-rod side not have air? The rod side can have air at all times in some applications, but the non rod side must be vented in one selection at least. The only way the piston will move out is when the rod side has air and the non rod side does not. The rod side has to be at a higher pressure than the non rod side to move the piston away from the trans case.

1st let me state, I have no experience on the Mack transmission in question, however I can answer your 1st question. Yes it can be normal to have pressure to both sides of a piston, Eaton does this on theirs. Because the rod takes up some area on the rod side, that "working" area is smaller than the other side, so when pressure to both, the piston moves to the rod side direction, when the back is vented the piston move the other way.

I drove a IHC firetruck that had that shift pattern, also my parts Fleetstar did also. odd, but not on common. 1stwas really low and not used when on hard pavement.

I don't know how they do it on your engine, but a lot of duel ign engines are designed to be run on both, all the time. They will run on one, but with reduced power. They are "starting the fire" at opposite sides of the cyl, and when you only burn from one side, power is lost and economy goes to hell. I have a duel ign Buda.

I am not a fan of "all under the cap" electronic ign. May be it was 'early days" but many had trouble with them failing. I am working on fitting a Chry reluctor to a Delco dist. If I ever get the project done (I'll post here, but don't hold your breath) then any remote control ign box could be used. For a "hobby/show"vehicle that doesn't see many hrs on the engine, points will last a long, long time.

several hits on the net for That Norther rad is about a grand, a few others in that price range.

I used to have some pin type shoes in 4" but when I looked in my core pile, all I could find were 15x4Q's. I much prefer the pin shoes on the narrow steer brakes. I forgot all mine were the more common 15 x 4

My 90 deg is square drive, so that will not be a help, my "777" ratio box is tang drive but I don't know if the parts interchange with the 90 deg, or not, I suspect not. Hippy's place or other speedo shop would likely be a better bet.

Mack wasn't the only one to use seals and greased bearings. There are a number of ways it was done.

Checked to see what I have. I have a 777 ratio box and a plain 90 deg but it has 5/8" threads and those look to be 7/8's

Another thing about "swaps" is they are never simple, yes the cut-off may not be that expensive, but then there is all the little stuff that adds up like driveshaft changes, frame splicing if not trying to bolt in. Getting replacement drums made may be the most expensive brake job you ever do, but as long as the shoes can be re-lined (shoe table not damaged) and the wheel cyl castings are not damaged, it still may work out cheaper in the long run. You are then left with something that is factory and not butchered, not only is it correct, but down the road it will make other repairs more straight forward. Take time to assess what you have now, and if drums are the only hurdle on the rear of the truck, I would advise getting them made. You may be able to "hook up" with other looking for those drums to make a "group buy" to bring the cost/unit down.

Just looking though Webb's catalog, I find 3 numbers that match the pilot, mounting hole and brake spec's but not surprising all are being discontinued. I found a few "hits" on those numbers, but unless you find one sitting in someones warehouse that they want to get rid of, it looks like Durabrake, is your best bet in this country. If you are having one made, then they should be able to make an exact fit. Problem with changing rear axles, is IIRC this truck is on juice brakes, so that would preclude swapping a more common and likely air braked axle. I would be looking for a minimum of 2 no matter the other one you have is still in one piece. Other than the above spec's the most important will be the hub mount to brake shoe measurement, that has to be close or be able to be machined to that spec.

The next video you post will be another shop putting the Cummins block back together!

https://www.durabrake.com/brake-drums/ In there "About us" section seam to say they make drums to order and prototypes

Give us the two measurements I asked for and see what can be found. we already know it is 15x 5 brake. needed are the bolt hole circle and the pilot diameter.