New to the forum, looking to buy a 90 M923a2

[KK4PGM]

Hello everyone, I hope everyone is doing well. I'm new here & I'm seeking some advice & in a bit of a hurry so I apologize for throwing this out there. To sum up an extended story, I've come across locally a 90 M923a2 truck for sale. I've visited the lot 3 times over the last 8 days & test drove it yesterday. For the most part it's in decent condition (to my amateur(ish) eyes). I'm very mechanically knowledgeable (although diesel is somewhat new to me), & have given it several hours of looking over. Asking price is $7k, down from the original $8k due to a few issues I've found. To name what I've found, the fuel tank is very dirty inside. Nearly 1liter of water has been drained from the tank since I first looked at it, either rust &/or gasket material from the sending unit is occasionally picked up through the fuel line. This is apparent as the dealer stated it was sluggish to get started & installed an Edlebrock electric fuel pump inline between the fuel line on the rail & the primer on the block. Using clear fuel hose, the chunks of black matter is visible....leading to my next point. The test drive started ok, but quickly became lack luster as the engine seemed starved for fuel & rpms dropped when attempting full throttle acceleration, speeds above 35mph & ANY incline. I'm assuming this may be from the partialy clogged fuel line but.....ideas from yall are absolutely welcome. The tachometer gear is broken from in front of the mechanical fuel pump, & there is a very minimal leak from the left rear wheel hub seal. The drivers door window is spider webbed & needs replacing, caused by the window frame being out of alignment & the door being shut causing the frame to make contact with the cab. Otherwise, spots of rust are all I could find. Tires hold air, have around 80% of tread & it idles fine. I have given him until tomorrow to make my decision, he will hold the price of $7k until Tuesday where it goes back to $7500. Transmission shifts well, bed does have benches (no canvas). No spare tire, all new vacuum/airlines, brakes work FANTASTICALLY, spliced in electric fuel pump allows for instant startup, other than wheel hub nothing leaks, no worrying amount of blowby. So, if your still here THANK YOU! Would this be a worth while buy, is the price fair, things I should go back & look at or be concerned over? Any & all help is very much appreciated.

 

[M35fan]

Welcome to Steel Soldiers! From the picture, I would say that is a good looking truck. I do not claim to be a 5 ton expert by any means, hopefully some of the members who are will chime in. Here is my two cents:

All of the performance issues that you describe could be caused by dirty fuel. If it were mine, I would clean or replace everything fuel related from the tank to the I.P. The big concern would be if any trash/water made it past the filters to the injection pump. Could get expensive rebuilding or replacing that.

Otherwise it sounds like a pretty solid truck and a decent price. If you had more time, I would suggest asking one of our members who is local to you to help out with an inspection. I see from your profile that you're in NC. There are several members near you.

Good luck to you. Please keep us posted.

 

[kendelrio]

Welcome to the site! I am by no means a 5 ton expert, but I also own a 1990 M923A2.

For the price listed, that seems like a good deal. Understand though, the biggest thing these beasts demand is time. You will be spending a lot of it tracking down the fuel issue and maintaining her.

As far as the fuel issue, as stated I would do a thorough cleaning and changeout of the lines, tank etc.

If you pull the trigger, download the tech manuals and explore them. If you have any issues finding or understanding them, feel free to reach out to me and I'll be glad to help.

There are also a lot of suppliers for the parts youll need and many of us are glad to help with knowledge, so don't be worried about asking for help.

Good luck and enjoy!

 

[Mullaney]

Hello everyone, I hope everyone is doing well. I'm new here & I'm seeking some advice & in a bit of a hurry so I apologize for throwing this out there. To sum up an extended story, I've come across locally a 90 M923a2 truck for sale. I've visited the lot 3 times over the last 8 days & test drove it yesterday. For the most part it's in decent condition (to my amateur(ish) eyes). I'm very mechanically knowledgeable (although diesel is somewhat new to me), & have given it several hours of looking over. Asking price is $7k, down from the original $8k due to a few issues I've found. To name what I've found, the fuel tank is very dirty inside. Nearly 1liter of water has been drained from the tank since I first looked at it, either rust &/or gasket material from the sending unit is occasionally picked up through the fuel line. This is apparent as the dealer stated it was sluggish to get started & installed an Edlebrock electric fuel pump inline between the fuel line on the rail & the primer on the block. Using clear fuel hose, the chunks of black matter is visible....leading to my next point. The test drive started ok, but quickly became lack luster as the engine seemed starved for fuel & rpms dropped when attempting full throttle acceleration, speeds above 35mph & ANY incline. I'm assuming this may be from the partialy clogged fuel line but.....ideas from yall are absolutely welcome. The tachometer gear is broken from in front of the mechanical fuel pump, & there is a very minimal leak from the left rear wheel hub seal. The drivers door window is spider webbed & needs replacing, caused by the window frame being out of alignment & the door being shut causing the frame to make contact with the cab. Otherwise, spots of rust are all I could find. Tires hold air, have around 80% of tread & it idles fine. I have given him until tomorrow to make my decision, he will hold the price of $7k until Tuesday where it goes back to $7500. Transmission shifts well, bed does have benches (no canvas). No spare tire, all new vacuum/airlines, brakes work FANTASTICALLY, spliced in electric fuel pump allows for instant startup, other than wheel hub nothing leaks, no worrying amount of blowby. So, if your still here THANK YOU! Would this be a worth while buy, is the price fair, things I should go back & look at or be concerned over? Any & all help is very much appreciated.

.
Welcome to the Outfit!

Seems to me that the price is reasonable and the truck looks good from the one picture that you posted. I have to agree with @kendelrio and @M35fan and their opinion that fuel is most likely where your problems are. Draining and cleaning the fuel tank(s) and changing the fuel filters should be first priority. Some fuel additive might be a good investment too.

Definitely grab the TM's (Technical Manuals) here.
Your new-to-you truck will be considered part of the M939 Series of truck, and a link to those books are below.

TM's for the M39 Series 5-ton

Listed below are a number of the TM's for the 5 ton and up trucks. To save them to your computer, right click, select "save as" LO9-2320-211-12.pdf LO9-2320-211-12 Lubrication order for M39 Series 5-Ton truck. TM9-2320-211-10.pdf TM9-2320-211-10 Operator's Manual for 5 ton M39 series trucks...

www.steelsoldiers.com

One more useful thing... The Spreadsheet. There is a spreadsheet maintained by one of our members that has the part numbers for filters and other parts that can be secured locally at the local O'Reily's or NAPA (etc).

5 Ton Parts List- copywrited 2021

Sheet1 r,VENDOR,PART #,VENDOR,PART #,VENDOR,PART # M939A2 & M915 PARTS AT THE BOTTOM OF THE PAGE SYSTEM CAPACITIES Cooling System Capacity M939A0/1 w/ NHC250 Oil Capacity w/ Filter (w/o filter),27 Qts (23 qts) M939A2 Oil Capacity w/ Filter (w/o filter),20 Qts (18 qts) Allison Fluid Capacity Dry...

docs.google.com

 

[98G]

If i were selling the truck, I'd fix the (most likely fuel) issue and then price it somewhere around $12-15k.

If buying the truck, you're gambling that it is in fact a fuel issue. You can replace everything from the tank to the IP pretty trivially, and rebuilding the IP is somewhere around $550.

Value of the truck , with all issues fixed, is certainly >$10k. Probably more like $15k.

As a pure exercise in economics, it's probably worthwhile as a fix and flip.

As an exercise in acquiring a good truck to keep, it seems like a good gamble.

Worst case, you have to transplant a powerplant into it. At that point you still wouldn't be far in the hole.

I'd do it. I'd grab it, then start by cleaning the tank and replacing all soft lines between the tank and the lift pump. If that didn't fix it, I'd have the IP rebuilt.

If that didn't fix it, that's where I'd run out of ideas and enlist someone with a higher level of competence.