M931A1 NEW OWNER

[zeik]

Hi guys. Just purchased my first m931a1. Im fact my first military truck. Im in Atlantic Canada. Crossing the border to bring it back was not trouble free. About a 150 km drive with a thirty plus year old truck I've never seen or driven was little nerve wracking. HAAAA. Start up wasn't bad little ether fired right up. Noticed right away an air leak. Parking brake wouldn't release. I was smart enough to bring two crates of tools, repair solids and liquids and tape, ties. Managed to crudly fix line. Got brake off. Thank God for Mike at the package depot who received my truck from shipping in calais Maine. He let us put truck in his shop to thaw and drain the lines and tanks were all frozen. MIKE you are the best. Finally on the road, through the border check points. The truck was running good. The parking brake light and buzzer would not shut off that drove us nuts. Any ideas? We played musical doors cause the handles were stuck at one point or another. I don't think oil pressure gauge is working the needle is bent. The speedometer or odometer isn't working so what I thought was a 1700 mile truck I was buying i now have no idea. I am aware that I will need to change all fluids. Check all air and fuel lines, adjust brakes, belts and hoses on a truck this age that sat a lot. Any ideas on my current problems and ANY OTHER ADVISE on things I should be aware of on these trucks I would apreciate. We finally did make it home without breaking down. Mission accomplished. I got big plans for this truck which I will discuss and post about another time with my questions after I have scoured this site for answers first. I joined this group in hopes of having access to the knowledge you guys have earned the hard way. That is usually how I learn too. Haaaa. I look forward to digitally speaking with some of you guys. Thanks in advance. Here's a pick of the truck 1990 model.

 

[silverstate55]

Nice hardtop! Welcome aboard!

You’ll probably need to service or replace the air dryer. Also check the flexible fuel lines from each tank for cracking; if they show any signs of cracking, replace them all…that will resolve any issues with air seeping in to fuel system & causing you to lose your prime.

Since your truck has the 14.00 Super Singles, these are known to bounce & vibrate at highway speeds, and this causes cracks in your fuel tank pickup lines at/near the fuel tanks (And cause loss of fuel prime). I even had a pickup tube fall out inside a fuel tank; after fishing it out of the tank I had it brazed to prevent it from happening again.

The grease fittings for the short jack shaft between the transmission & transfer case are a real pain to get greased.

Others will be along shortly to offer better advice. Congratulations on your purchase, and interested to hear about the border crossing story.

 

[zeik]

Nice hardtop! Welcome aboard!

You’ll probably need to service or replace the air dryer. Also check the flexible fuel lines from each tank for cracking; if they show any signs of cracking, replace them all…that will resolve any issues with air seeping in to fuel system & causing you to lose your prime.

Since your truck has the 14.00 Super Singles, these are known to bounce & vibrate at highway speeds, and this causes cracks in your fuel tank pickup lines at/near the fuel tanks (And cause loss of fuel prime). I even had a pickup tube fall out inside a fuel tank; after fishing it out of the tank I had it brazed to prevent it from happening again.

The grease fittings for the short jack shaft between the transmission & transfer case are a real pain to get greased.

Others will be along shortly to offer better advice. Congratulations on your purchase, and interested to hear about the border crossing story.

Thanks for your two cents I'll definitly take it. I haven't had time to really move the truck since I got it home. It's going in to get fifth wheel taken off, new hitch plate for bigger pintle and 2.5 inch receiver , tail light relocation and a complete service and check over before I start to use it for towing my equipment around. My plan is to check all the items you mentioned as well. Im sure I'll have a million questions. After this construction season the plan is to install a dump box on back. Don't know if scissor or front mount hoist yet. Possibly a plow if I get to it in time or on the list for the following winter.
Thanks again

 

[silverstate55]

The tech manuals for your truck are available for download, so I would encourage you to do so if you haven’t already. The A1s with the NHC-250 Cummins has a lot more low-end torque than the A2s so it will be perfect for towing for you. There is a LOT of great info on this site about these trucks.

As has been pointed out in other threads like these on M939-series trucks, full fluid & filter changeouts are your first priority. And, make sure you grease everything thoroughly (found in the LO lube order).

The lack of other comments here is pretty much good testimony to how reliable they are.

 

[US6x4]

Don't back up with the transfer case in low (no bueno for the t-case) and when you shut down the engine, shut off the engine switch first then after the engine is done rotating shut off the battery switch. This prevents frying the voltage regulator in the alternator.