HMV Field Repairs

There are probably as many reasons for owning an historic military vehicle (HMV) as there are individuals who own them. The experience means different things to different people. For me, the reason for owning an HMV is driving it. I think anyone who hasn’t cruised a desert back road on a warm moonlit night in their jeep, MUTT, M37, M715, or most other HMVs with the windshield down has really missed something... besides the occasional bug in the face. I also think that owning an HMV should be fun. A breakdown in the field, however, can change that fun into plain agony — if you aren’t prepared.

HMVs ARE SIMPLE MACHINES

I learned many of these trouble-shooting procedures and repairs the hard way during my jeep summer. One of the most important lessons was: An HMV owner must be self-sufficient when it comes to tools and spare parts, as well as possessed of a good basic mechanical knowledge in regard to trouble-shooting and repairing their vehicles.

Let’s assume you’re going to take your HMV on a trip. Maybe it’s only fifty miles to a swap meet via the Interstate, or maybe you want to spend a weekend fishing at some remote mountain lake, or perhaps you’re going out for a month exploring ghost towns in the desert. No matter where you’re going, you’ll probably be traveling in a vehicle that is forty, fifty or maybe sixty-plus years old. Even the most basic replacement parts such as water and fuel pumps, generators, starters and often even a head lamp bulb, won’t be easily found along the way.

To some degree, this disadvantage is offset by that fact that most common HMVs are simple machines that are easy to work on with basic tools. What isn’t there can’t go wrong, and as long as your vehicle is in good shape to begin with there shouldn’t be a lot that breaks on a trip that can’t be fixed or at least be patched together by an average person with a basic tool set, some on-board spare parts, and rudimentary mechanical skills.

Adopt the “P” principle: Proper Planning Prevents Pee-Poor Performance.

As applied to most common HMVs, this means that every dollar and hour spent on preventive maintenance at home will usually save you ten times that much in money and hours in the field. Having spare parts and tools aboard your vehicle can often mean the difference between a living a dream or enduring a nightmare; and most people who have ever broken down on a freeway and had to call a tow-truck will probably agree.

SOONER OR LATER,YOU’LL HAVE A BREAKDOWN

One second you’re been rolling along in your HMV, looking forward to a hot meal and a shower. But then, you are coasting in eerie silence on an almost deserted highway.

If your engine should suddenly quit like this, and you’re not on a steep downgrade, step on the clutch and start looking ahead for a safe place pull off road while you’re still moving. On an outback trail, it won’t matter much where you stop, though you don’t want to end up blocking the trail—even if only three vehicles a year use that road, they will all show up if you’re blocking it!

On a highway or freeway your choice of stopping places could mean the difference between having the time you need to get your vehicle going again or an overpriced tow to a scam-joint garage. If you were on a downgrade or a level stretch of road when your engine quit, you might have time for a few quick tests while you’re still in motion. Momentum, like battery power, should always be used to best advantage. Once it’s gone, it’s hard to replace.

DIAGNOSING THE PROBLEM

Basically, a gasoline engine needs two things to run: Fuel and ignition. It may help to visualize your fuel and ignition systems as chains of components, each chain having a beginning and an end.

Your fuel system chain begins with gas in the tank and ends at the carburetor, while your ignition system chain begins at the battery and ends at the spark plugs. You can usually figure out what is wrong by working along the chain of components step-by-step.

If you follow these procedures in order instead of randomly skipping around (and assuming you’ve taken the advice in regard to spare parts and tools) you will usually be able to get your vehicle going again fairly soon. It’s okay to trust your instincts up to a certain point—such as checking to see if the coil wire came loose or a fuel line broke—but beyond these hunches, it will almost always save you time and frustration if you track down the problem in a logical order using step-by-step test procedures. You should begin this testing while you’re still in