Just picked up a M54A1C fire truck.

[jjmartinez1982]

Decommissioned fire truck. The tank is rotted out and those branch rails have got to go. Runs pretty good though and shifts nice. Also gonna need at least 2 new tires. Will be using it mostly as a toy/show piece on the ranch.

 

[NDT]

Welcome, looks like a great start! Got a day or two of torch work ahead of you! The FD put a GMC front bumper on it, the stock bumper has no holes. Post up your progress.

 

[jjmartinez1982]

Welcome, looks like a great start! Got a day or two of torch work ahead of you! The FD put a GMC front bumper on it, the stock bumper has no holes. Post up your progress.

Thanks for the info! I’ll take as much of it as I can get. I’ve been glancing at all the manuals. I’ll definitely keep everyone updated. Also, this model, unfortunately, doesn’t have a winch.


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[jjmartinez1982]

Drove it 40 miles back to the house. It made it! Needs a headlight switch and I need to figure out why there are 2 other “master disconnect” switches on the dash. Looks like a neat little project!


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[fasttruck]

I hope the previous owner has not "customized" the wiring to the point of destruction with unqualified personnel with unauthorized parts and tools working on it. Grease is cheap, parts expensive. Get ba lube order and read it. There ought to be at least 40 grease points on a cargo truck, 4 on the handbrake alone. Neglect them at your peril.

 

[Tracer]

Thanks for the info! I’ll take as much of it as I can get. I’ve been glancing at all the manuals. I’ll definitely keep everyone updated. Also, this model, unfortunately, doesn’t have a winch.


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Unless the FD torched off the ends of the frame, you can install a PTO winch on your truck. I installed one on my M35A2C without to much trouble. Also being an M54A1, does your truck have the ENDT Mack engine?

 

[jjmartinez1982]

I hope the previous owner has not "customized" the wiring to the point of destruction with unqualified personnel with unauthorized parts and tools working on it. Grease is cheap, parts expensive. Get ba lube order and read it. There ought to be at least 40 grease points on a cargo truck, 4 on the handbrake alone. Neglect them at your peril.

Doesn’t appear to have been ruined by the previous owner. Looks like all they did was run some wire into the cab for the lightbar and radio power. Everything else looks ok except for a loose connection that, as best as I can tell, goes to one of the gauges. It looks like an RCA plug. I’ll check tomorrow when there’s better lighting.

Quick, maybe even dumb, question: is the headlight switch needed for the push button start to work? I see 2 wires going from the start button to the giant plug that goes into the headlight switch. At least, that’s what it looks like in the dark. We have to bump start it with another vehicle at the moment.


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[jjmartinez1982]

Unless the FD torched off the ends of the frame, you can install a PTO winch on your truck. I installed one on my M35A2C without to much trouble. Also being an M54A1, does your truck have the ENDT Mack engine?

I’m still getting to know these vehicle but it’s supposed to have the 627 I believe. Any way to quickly ID it?

Also, thanks for the tip on the winch. Now I need to look for one.


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[Tracer]

I’m still getting to know these vehicle but it’s supposed to have the 627 I believe. Any way to quickly ID it?

Also, thanks for the tip on the winch. Now I need to look for one.


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Try to find a complete unit. Winch (with cable), PTO (power take off), drive shaft, cab control levers and linkage, and frame extensions. The TMs will give you parts & part numbers, and how to install. A Steel Soldiers member may have a good clean complete unit for sale.

 

[Tracer]

This is a Mack ENDT-673 engine out of an M54A1. If yours is different, post pictures.

 

[jjmartinez1982]

View attachment 758371View attachment 758372View attachment 758373 This is a Mack ENDT-673 engine out of an M54A1. If yours is different, post pictures.

My memory says that looks like the one in my truck. I’ll look again in the daylight tomorrow and post back. Thanks.


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[fasttruck]

Reference the wires to the starter button: the trucks were built so that it was not necessary to turn on the lights to operate the starter. Some of the wheeled self propelled cranes did require the light switch to be on to energize the starter. Look in the publications forum on this site for the applicable -20 or organizational maintenance TM for this truck. It will show how they were originally wired(circuit diagrams) and identify what the wire numbers are. The TM number can usually be found on a data plate on the right side of the dashboard.

 

[SCM35A2]

Welcome to the site, nice truck!

 

[jjmartinez1982]

Reference the wires to the starter button: the trucks were built so that it was not necessary to turn on the lights to operate the starter. Some of the wheeled self propelled cranes did require the light switch to be on to energize the starter. Look in the publications forum on this site for the applicable -20 or organizational maintenance TM for this truck. It will show how they were originally wired(circuit diagrams) and identify what the wire numbers are. The TM number can usually be found on a data plate on the right side of the dashboard.

You’re saying there’s a number on one of those plates that indicates which manual I need for repairs and information? I’ll check it out when I get home after work.

I looked through some of them last night and couldn’t find a wiring diagram. I was hoping I would. Closest thing I found was a troubleshooting flow chart that ends with “repair or replace front harness”.

Again, I appreciate all the info.


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[jjmartinez1982]

Welcome to the site, nice truck!

Thanks! I’ve been wanting one for a few years now. Finally had one basically fall into my lap.


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[jjmartinez1982]

Ok upon closer inspection it appears that I don’t know what the previous owners tried to do. Batteries were wired in a curious way. One battery had the positive wired to the vehicle ground. Both negative posts are connected. Then the other battery positive wire was routed to one of those master disconnect switches. What in the world?


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[fasttruck]

I believe the relevant TM is 9-2320-211-10 and 20. The 20 manual should include a wiring diagram and an explanation of what the numbers on the wires identify. On a 2 battery truck the lines to the starter and the ground originate from the appropriate terminal on the ends of the batteries closest to the frame and the other positive and negative terminals are wired together to make the 2ea 12 volt batteries operate in series. On a 4 battery truck each pair is wired in series and the pairs are wired parallel to make enough electrons to jolt a NH250 into life on a cold day. The batteries are contained in a metal or plastic box with terminals that are easy to disconnect so in the artic you can easily place the batteries in a warm place so they will have enough energy to start the truck before they get cold again.

 

[jjmartinez1982]

I believe the relevant TM is 9-2320-211-10 and 20. The 20 manual should include a wiring diagram and an explanation of what the numbers on the wires identify. On a 2 battery truck the lines to the starter and the ground originate from the appropriate terminal on the ends of the batteries closest to the frame and the other positive and negative terminals are wired together to make the 2ea 12 volt batteries operate in series. On a 4 battery truck each pair is wired in series and the pairs are wired parallel to make enough electrons to jolt a NH250 into life on a cold day. The batteries are contained in a metal or plastic box with terminals that are easy to disconnect so in the artic you can easily place the batteries in a warm place so they will have enough energy to start the truck before they get cold again.

Thanks for the tips. I’ll look into that specific 20 manual for wiring diagrams and I’ll be flipping the batteries to wire them properly today after work.


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[fasttruck]

Attached is a pic of battery configuration on a 2 battery truck. Rear right is positive, rear left ground, front positive and negative hooked together to make it a series arrangement. Just for giggles, does your truck have the regular military 3 lever light switch ? Is it still straight 24 volts. Fire departments are notorious for adopting the wiring for 12 volt lights and radios with untrained personnel with unauthorized tools and parts doing the destruction. If the truck has a commercial light switch in place of the military then God help. Aforementioned problem with wires from the light switch to the starter does not seem to be stock. The military spent millions of dollars to engineer these trucks and attempts to make them into something else usually are not good.

 

[jjmartinez1982]

Attached is a pic of battery configuration on a 2 battery truck. Rear right is positive, rear left ground, front positive and negative hooked together to make it a series arrangement. Just for giggles, does your truck have the regular military 3 lever light switch ? Is it still straight 24 volts. Fire departments are notorious for adopting the wiring for 12 volt lights and radios with untrained personnel with unauthorized tools and parts doing the destruction. If the truck has a commercial light switch in place of the military then God help. Aforementioned problem with wires from the light switch to the starter does not seem to be stock. The military spent millions of dollars to engineer these trucks and attempts to make them into something else usuallyView attachment 758588 are not good.

It does not have the 3-switch light switch. I don’t think the person installing the batteries had any idea what they were doing. There was no ground connected at all. One positive post went to one of the aftermarket battery disconnect switches on the dash where it put-tails. I assume, due to the other positive lead not attached to anything, that this lead is supposed to go to the starter and generator (alternator). The other battery’s positive post went to the ground stud on the frame. Both negatives were wired together. No lights or gauges (except speed, tach, and air pressure) work and the truck has to be pull-started with a clutch pop.

The wiring they had for their aftermarket stuff ran off of one battery. Doesn’t look like they mutilated any of the original light/gauge wiring though. I’m still digging into it.

Here’s a pic of how the batteries were wired:

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