Getting an M939 Running for the First Time in Years

[71DeuceAK]

Alright, I tried the search for this but didn't have any luck; my apologies if there already multiple similar threads out there that are along the same lines as this.

I'm looking into saving an M939 from a local junk yard. I'm going to look at it in detail on Friday or Monday hopefully but in the meantime I've been reading threads and researching things I need to know as despite years of lurking here this would be my first actual acquisition; despite reading up on them daily for 3 years now and having specs memorized and knowing them well from years of looking at every part of them in pictures I still have hardly any in-person experience; I've sat in them a few times and ridden in one exactly once.

Nevertheless, when/if I get it, and have it on a storage lot and the temperatures finally warm up (April/May) and I start looking at maybe trying to go over there and see if it'll run (assuming no major parts missing, there's another thread of mine on all the possible issues I already have going) any special recommendations for starting one of these for, I assume, the first time in years?

A friend who knows the particular salvage yard this is at and who has repaired his car there many times told me it didn't used to be there last summer he doesn't think, so it may have driven there on its own and still be complete; it's still in the front parking lot, not the back forty yet.

Sooo...What should I consider besides a couple Group 31 batteries and some starting fluid and bleeding air at injector lines and maybe pulling the mushroom cap and having someone standing by to snuff it out in the event of an engine runaway scenario? That and dry rotted rubber fuel lines and bad fuel and rust and other "sitting" issues that happen with any vehicle...

Of course I've read plenty of horror stories of motors dropping liners, tires blowing out, etc but I'm talking trying to make it make smoke and noise for the first time (presumably, assuming the worst) in years.

Thanks! If I get this thing I'm going to have LOTS of questions and be trying not to crash the site's servers with my heavy use of the search function...You guys have already helped me tremendously over the years.

 

[Trailboss]

A few points from my experiences. Assuming the critical parts are not missing, fluids OK, good fuel in the tank and the lines bled:
1. Several cans of starter fluid.
2. Search on how to bypass the black box if a tap with a hammer doesn't get the starter to engage.
3. Two group 31 batteries should work for awhile, but a slave to another running 24v vehicle will help a LOT if it doesn't start immediately.
4. Sledge hammer to break loose frozen brake drums.
5. If an 8.3 engine, something to tie up the shutoff solenoid if it won't stay up.
6. Watch the air pressure to make sure it builds up and that the compressor shuts off when it's supposed to.
7. Check the brake cans to see if they're caged, or that the cage bolts are available.
8. Once it fires off, keep the engine speed above 1000rpms for a couple minutes to keep it from dying. This will help purge the fuel system.

 

[71DeuceAK]

Thanks!!

I'd heard of the PCB tapping/bypassing, along with the good old "sledgehammer on the brake drums" one before along with the "zip tie the shutoff solenoid", but good advice to have reiterated nevertheless! This would be long after getting it, when I finally have time and money to really tear into it besides parking it in the meantime.

 

[Jbulach]

I think you have been around here enough to know the visual basics, but remember a vehicle like this was most likely not just driven to the junk yard. After the hours of looking the truck over, that I think you will be doing, if all appears to be intact, and before handing over the cash, crack all the drain plugs to check for and drain water (ice, almost forgot) off the bottom of the fluids. I would also at least try to bar the motor over, if you don’t have the means, or you cant get the starting system to cooperate.

Remain calm, the truck is not likely going anywhere soon, make several visits if necessary to make sure your not getting in over your head. Long shot but check and see if they have a secure way of storing it for less, maybe since they’re a U-pull, they would even allow a reasonable amount of maintenance/repair to be done on site?

Good luck, get a good look at it, then report back with what your looking at, and questions, then... we can more wisely help you spend your money!!!

 

[BenRoberts]

If it does run make sure the glad hand valves are closed or you will end up like me dumping the air out every time you apply brakes. Also make sure the caging bolts are out

 

[71DeuceAK]

Thanks guys!

 

[simp5782]

Check the oil. Install Batteries. Case of ether. 5 gallons of fuel. An SAE 1/2" male fitting to 3/8" hose barb. Bypass the tank. Prime it up and fire it. Shouldn't be any issue. I have had good luck at 0 degrees getting 3 sitting trucks to fire up lately.

Sent from my SM-G935P using Tapatalk

 

[71DeuceAK]

Thanks for the info, Wes! I doubt I'll try to make it run until weather warms up but I was hoping it'd be fairly simple and it looks like I was right thus far...

 

[71DeuceAK]

OK! End of the story. Turned out the truck had a loving owner and wasn't left for dead. So although I didn't acquire it, the story has a happy ending. It ended up being a really nice M925, albeit buried in snow at the time. Believe it or not, relating this story later landed me a connection which later turned into a possible job offer. A post here on Steel Soldiers asking who it was who has the truck there later on in an Alaska members thread resulted in meeting a fellow member here, who is, now, later on, about to become my landlord. It's funny how random inanimate objects create their own bizarre stories to say the least.