By Steve Turchet
Part One of this article (MVM April 2015, no. 173) covered the development and history of the M151 Military Utility Tactical Truck. Part Two (MVM June 2015, no. 175) offered suggestions about buying a MUTT. And finally, Part Three offers advice on caring for MUTTs. So, you decided to buy a MUTT. Hopefully, you made an informed purchase – possibly aided by Part Two of this article. You have traded cash or check for the vehicle’s title. What now?
Circumstances vary a lot, of course, including the condition of the vehicle, and whether or not it’s presently drivable. Unless you’re completely confident that both yourself and the MUTT are fully “Mission Capable” and have only a short distance to travel – say less than fifty miles – it’s safer not to drive the vehicle home. Nor is it generally a good idea to have the former owner drive it to you. Instead, it’s usually best to take the vehicle home on a flatbed or trailer.
Buying an historical military vehicle (HMV) is usually not the same as purchasing an ordinary used vehicle from a dealer or private party. I’ve bought hundreds of vehicles over the years. For myself as well as other people and companies I’ve worked for, it’s been my experience that damage or misfortune often occurs when attempting to drive such vehicles for any distance without first completely servicing them.
Also – especially if cash and title have been exchanged – the vehicle’s former owner may not put much TLC into driving the vehicle to you. While it will probably arrive in one piece, I’ve met many people who can put a thousand miles of wear on a vehicle by driving it less than a hundred. If you were an informed buyer, you already knew that terms such as “turn-key” or “drive anywhere” are only a seller’s opinion or advertising fluff. Your new MUTT will only be “drive anywhere” when that’s your own experienced opinion.
A THOROUGH EXAM
In any case, we’ll assume your MUTT is now in your driveway or garage. This should be when the really important inspection and servicing begins.
First, if you haven’t already, buy a service manual (TM) for whatever series MUTT you’ve acquired…M151, M151A1, M151A2, or variant. It always surprises me that some people pay thousands of dollars for an HMV, yet won’t pay twenty bucks more for the appropriate service and repair manual. Still, you will probably find that keeping your MUTT in good, dependable running condition (Mission Capable) is not always a matter of doing everything by the book, but rather an ongoing process of checking things out, performing basic service at regular intervals, and fixing things before they break.
Good maintenance also involves getting to know your MUTT and caring for it with a long-term mindset. The latter point seems to be a new concept for many younger folks in the U.S.A. who have been raised to accept planned obsolescence, where things are thrown away simply because a new model has come out, and/or it’s cheaper to buy something new than fix something old. Therefore, when it comes to an historic military vehicle, a person may have to learn a whole new philosophy in regard to caring for it. The idea is not only to keep your MUTT running, but to make it better and more dependable as time goes by.
As suggested, this process should start as soon as you get your MUTT home. Resist that adolescent urge to drive it right away and show it off to friends like a teen with his or her first ride.
Instead, always assume the worst, no matter what your pre-purchase inspection revealed. Assume that the gear oil is low, and /or worn out in the transmission, transfer case and differentials. Likewise, the engine oil.
Assume the wheel bearings need repacking, the MUTT is decades overdue for a lube job, and the brake fluid is twenty years old. Assume that all components, connections, drive belts, hoses, and nuts and bolts are loose.
Inspect all the brake lines, the steel ones for rust or damaged spots, the rubber lines for cuts, cracks or deterioration from age. Check all the universal joints for looseness, and put a wrench on their mounting bolts to make sure they’re tight.
Check the tightness of the engine, transmission and transfer case mounts. If a mount is badly deteriorated or broken, it should be replaced before driving the vehicle.
In other words, change the status of your MUTT from an unknown stranger to an intimate friend.
Here’s the official M151A1 Army checklist:
#1. Grille: Damaged. Badly rusted.
#2. Bumper: Missing. Damaged. Badly rusted.
#3. Lifting Shackles: Missing. Damaged. Safety pins or chains missing or broken.
#4. Headlights: Broken. Not working. Painted-over. Loose mounts or connections.
#5. Blackout Marker Lights: Missing. Damaged. Not working. Loose mounts or connections.
#1. Fire Extinguisher (behind driver seat): Charged. Not tagged. Bracket loose or broken.
#2. Outside Rearview Mirror: Missing. Cloudy, cracked, or broken. Painted-over. Head or bracket rusted or damaged. Not adjustable.
#3. Body Panels: Badly dented or damaged. Rusty. Seams cracked. Strap eyes crushed. Bent or missing top bow hold-downs. Damaged, missing, or painted-over reflector.
#4. Axe: Missing. Rusty. Damaged handle. Loose or missing hold-down straps.
#5. Tires And Wheels: Lug nuts loose or missing. Studs bent, threads stripped or damaged. Cracked or bent air-drop eyes. Rims dented or bent. Tire bead not snug on rim. Valve caps missing. Incorrect tire pressure. Tires cut, damaged or badly worn.
#5. Fuel Tank: Filler cap rusted or missing. Gasket rotted or missing. Cap not in correct position for normal driving or fording. Tank leaking. Strainer missing, damaged or clogged. Objects under driver seat endangering tank or fuel lines.
#6. Blackout Driving Light: Missing. Damaged. Not working.Loose mount. Loose connection. Frayed wire.
#1. Same as left side in regard to body panels, tires and wheels, and reflector.
#2. Shovel: Missing. Damaged. Missing or damaged hold-down straps.
#1. Canvas (Top): Torn, damaged or rotted. Straps frayed or missing. Buckles damaged or missing. Windows cloudy enough to hamper vision.
#2. Trailer Lighting Receptacle: Damaged. Cover missing or broken. Missing or damaged cover spring. Gasket missing.
#3. Reflectors: Painted over. Missing or damaged.
#4. Fuel Container: Missing. Leaking. Damaged. Rusty. Cap missing or threads stripped. Gasket missing or torn. Missing or badly frayed hold-down strap.
#5. Pintle: Missing. Not lubricated. Damaged. Bent. Inoperable.
#6. Spare Wheel And Tire: Loose on mount. Tire flat, cut or damaged. Missing valve cap. Wheel bent or damaged.
#7. Body Panel: Badly dented or damaged. Rusty. Seams cracked. Strap eyes crushed.
#8. Lights: Broken. Not working. Lenses painted-over.
#9. Lifting Shackles: Missing. Damaged. Safety pins or chains missing or broken.
#10. Bumperettes: Missing. Damaged. Mounting bolts loose.
#1. Tool Box: Tools missing, broken, rusty. Cover bent, rusty or missing.
#2. Batteries: Cracked. Leaking. Cells low. Posts or clamps loose or corroded. Vents clogged. Hold-downs loose or damaged.
#3. Battery Box: Cover damaged. Clips loose or broken. Rusty.
#4. Windshield Wipers: Motors inoperable. Blades rotted or missing. Manual handles bent. Hoses leaking. Not enough slack to lower windshield.
#5. Windshield: Glass broken or badly cracked. Frame damaged or bent. Locking pins stuck. Securing strap broken or missing.
#6. Rearview Mirror: Missing. Cloudy, cracked or broken. Painted-over. Head or bracket rusted or damaged. Not adjustable.
#7. Seats: Covers torn. Frames bent. Retaining pins or chains missing. Retaining eyes loose or damaged.
#8. Instruments – Gauges: Broken, not working. Painted-over.
#9. Switches and Controls: Broken. Missing. Not working.
#10. Data Plates: Missing. Loose. Painted-over.
#11. Floor: Rusty. Damaged. Drains clogged.
UNDER THE HOOD:
#1. Safety Catch: Won’t hold hood up securely. Missing. Misaligned. Broken.
#2. Water Temperature Sending Unit: Not functioning. Connection loose. Wire frayed.
#3. Horn: Loose mount. Corroded. Not Working. Connections lose. Wires frayed.
#4. Fuel Lines: Crushed. Leaking. Frayed.
#5. Oil Filter: Loose. Leaking.
#6. Oil pressure Safety Switch: Loose. Corroded. Connection loose. Wire frayed. Not working.
#7. Oil Dip Stick: Missing. Bent. O-ring damaged or missing.
#8. Master Cylinder: Vent clogged. Cap missing or too tight. Brake fluid more than 1” below top level.
#9. Distributor: Cracked case. Loose. Screws missing. Loose or damaged cable connections.
#10. Vacuum Pump: Loose. Not working. Gasket leaking.
#11. Fan Belt: Loose. Slipping. Too tight. Frayed.
#12. Headlights: Not working. Broken. Wires frayed. Connections loose.
#13. Generator Regulator: Loose mount. Wires loose or frayed. Loose or corroded connections.
#14. Generator: Not working. Loose. Misaligned. Loose or corroded connection.
#15. Linkages: Choke, throttle and accelerator securely connected and operational.
#16. Oil Filler Cap: Missing. Damaged. Gasket missing or damaged. Chain missing or broken.
#17. Air Cleaner: Damaged. Oil level low. Needs service. Connections or hoses damaged or leaking.
#18. Engine Vent Valve: Cracked. Threads stripped. Connections loose. Leaking. Lines crushed or damaged.
#19. Intake Manifold: Bolts loose. Cracked. Gaskets loose. Leaking.
#20. Exhaust Manifold: Bolts loose. Cracked. Leaking. Exhaust pipe connection loose or leaking.
#21. Radiator: Cap missing. Cap gasket missing or leaking. Radiator leaking. Hoses damaged or leaking. Mounts loose or broken.
#1. Underbody: Plates, panels, cross-members rusted or damaged. Cracked welds.
#2. Drive Shafts and Universal Joints: Binding. Damaged. Bent. Loose.
#3. Differentials: Flange guard, washers or screws missing. Breather plug missing. Mounting bolts loose. Leaking.
#4. Shock Absorbers and Springs: Bent. Damaged. Badly rusted.
#5. Brake Lines: Badly rusted. Damaged. Crushed. Loose. Leaking.
#6. Parking Brake: Loose on support. Out of alignment. Return spring loose or damaged, Band worn out. Not working.
#7. Exhaust System: Badly rusted. Loose mounts and connections. Damaged. Leaking.
#8. Transmission/Transfer: Loose. Leaking. Breather clogged.
#9. Steering: Pitman or idler arms loose. Rods bent or damaged. Ends worn or loose. Too much slack in box.
#10. Radiator Drain Cock: Damaged. Clogged.
#11. Engine Oil Pan: Damaged. Bolts loose. Leaking.
#12. Speedometer Drive Cable: Loose. Broken. Damaged.
#13. Clutch Housing: Drain plug in blind boss (except when fording). Drain plug missing. (Early M151 drain plugs kept in tool box.)
You should be able to check all these things in a day, which should give you a good idea of your MUTT’s overall condition. This inspection should truly reveal how well – or not – the former owner cared for it.
Off the book, keep in mind that one size – so to speak – doesn’t always fit all. Unless you use your MUTT as daily-driver, off-road, or for actual work, its service and maintenance should also be a matter of common sense. For example, there are some maintenance tasks that should be performed no matter how much or how little your MUTT is driven… such as changing the brake fluid, renewing the engine coolant, and checking the battery water levels. The brake system should be drained, flushed, and the fluid renewed every two years. The simplest way to do this is to remove most of the old fluid from the master cylinder – a “turkey baster” may come in handy – add new fluid, then bleed the system, either using the two-person method, or solo with a power bleeder or vacuum pump, adding new fluid to the master cylinder until the system has been completely flushed and refilled.
WHAT ABOUT BRAKE FLUID?
The question often arises as to whether one should use conventional brake fluid or silicone fluid. The main advantage of silicone brake fluid is that it doesn’t attract moisture. On the other hand, silicone fluid tends to leak out of a system because it doesn’t swell the rubber parts in the master and wheel cylinders as much as conventional fluid. Silicone brake fluid is more expensive than conventional types, and often harder to find in the field. Silicone fluid may give a spongy feel to the brake pedal. While silicone brake fluid seems ideal for MUTTs that aren’t driven much, one should check the level often.
Antifreeze breaks down over time, is always being diluted by the addition of new water, and rust forms in the cooling systems of MUTTs that are only trailered to shows, just as it forms in vehicles that are driven daily. Engine coolant should be drained every two years by opening or removing the radiator drain cock and all the drain cocks or plugs on the engine. Then, with the engine running, new water should be added to the radiator until all the water coming out through the radiator and engine block drains looks clear. Close the drains and fill the cooling system with the proper mix of new antifreeze and water.
Many MUTTs that have not had their engines completely rebuilt in a shop (where the engine block is “boiled”), may suffer from overheating problems due to lots of rust scale and debris in the engine water jacket. It is unlikely you will be able to flush this stuff out through the small drain plugs. While there is really no substitute for “boiling” an engine bock, you may remove the soft plugs and dig out as much scale and debris as possible. Soft plugs are another item that should be checked occasionally for leakage or serious rust.
Likewise, old radiators often become clogged with scale and debris that simple flushing can’t remove. The only way to thoroughly clean an old radiator is to remove the tank and bottom and “rod-out” the tubes. But, unless you’re very skilled in the art of soldering, it’s best to have this professionally done.
If your MUTT has an expansion tank, check that it isn’t half full of sludge and rust scale. Radiator caps should be replaced about every five years, or when their gaskets begin to rot or become brittle. Keep both the cap’s gasket and the radiator’s filler neck clean, or the gasket may not seal and hold pressure.
While there are many cooling system flush products on the shelves of auto mart stores, most are not very effective and thus a waste of money.
Battery water evaporates whether or not a vehicle is used, so the cells should be checked frequently, and at least once a week in hot, dry environments. Add distilled water whenever possible, but any water is better than letting the cells get low. Once the plates of a wet cell battery are exposed to the air, they lose whatever percentage of power the exposed area produced. For example, if the plates in a battery cell are ten inches tall, and one inch of those plates is allowed to dry out, that cell will lose ten percent of its power. This is a permanent loss, and adding more water will not restore it.
The useful life of vehicle batteries varies a lot. How long a battery lasts is dependent upon many factors, including the quality of the battery to begin with, extreme heat or cold, and how the vehicle is used. Shock and vibration can shorten battery life, as well as hard-starting problems in which a battery is often run low. This can be compounded if the battery is not fully recharged. An example is a vehicle that sits most of the time so it doesn’t start easily, and then isn’t driven very far.
The average life of most wet cell vehicle batteries is three to five years. Most bargain batteries don’t last long beyond their warranties, while more expensive batteries may outlast their warranties by several years.
You usually gets what you pay for when it comes to vehicle batteries. Spending twenty dollars more for the best battery might save you money in the long run, since a top-quality battery may outlast two cheapies. A top-quality battery may also save you the price of a towing bill or off-road rescue by being strong enough to start your MUTT in extreme conditions… or if you simply forgot to turn off the lights.
Keep in mind that while an old battery may still start a vehicle and appear strong, it might not have enough reserve power for long periods of starter cranking. If you have any doubts about a battery’s condition – and/or the warranty period has been exceeded – you should consider replacement if the vehicle is going on a long road trip or out in the bush. MUTTs, as do most M-series vehicles, have two batteries, and both should be replaced at the same time. Replacing only one usually results in having to replace both again sooner than if both were replaced to begin with.
On the other hand, thousands of perfectly good batteries are replaced every year because they are thought to be the cause of hard-starting problems, when the actual cause is something as simple as loose or dirty terminal connections. Look at the battery clamps for fuzz or corrosion, and make sure they’re tight by trying to move them by hand. Also check battery cables for tightness where they connect to the starter, starter switch, solenoid, engine block, and vehicle body. The negative, or ground cable, is just as important as the positive cable.
PROBLEMS OF AGING
Many vehicle components age and become unreliable regardless of mileage or engine hours. Examples are electrical and ignition wiring, radiator and heater hoses, and fan and accessory drive belts. Things like these should be examined frequently. Check drive belts for cracks, fraying, or glazing on their inner surfaces. The latter usually indicates a belt has been slipping.
The most common cause of drive belt slippage is the belt being loose. Other more serious causes can be a generator, alternator, or water pump with bearings becoming stiff and about to seize up. This can be checked by removing the drive belt and turning the accessory by hand.
A generator, alternator, or water pump with stiff bearings should be rebuilt or replaced immediately. There is no way to judge when it may fail. Likewise, rebuild or replace any such accessory with bearings that squeak or feel rough.
A badly glazed drive belt will almost always slip, and should be replaced. Drive pulleys may also become glazed because of a slipping belt. If so, sandpaper can be used to roughen them for a better grip. Another thing to look for is lots of black dust on or around the front of the engine. This usually indicates a drive belt wearing out because of a loose or misaligned accessory. Some MUTTs came from the factory with improper generator mounting bolts that often came loose.
Fondle the radiator and heater hoses to see if they’re getting hard and brittle or developing cracks. On the other hand, a radiator or heater hose that feels very soft and squishy may be ready to fail because it’s decomposing. Old heater hoses usually break at their connections. When replacing such hoses, leave a little extra length. Then, if the hose breaks someday while out on the road, you’ll have enough extra to reattach it.
Hose clamps loosen over time due to expansion and contraction caused by heating and cooling, as well as vibration, and should be checked occasionally. On the other hand, over-tightening hose clamps can cause a hose to break. Sometimes, a radiator hose leaks, not because it’s too loose, but rather because a water inlet or outlet is rusty and rough, or pitted and corroded. Cleaning and smoothing a rust-scaled fitting with a wire brush, or replacing a badly corroded fitting, is better than over-tightening its hose. Gasket sealer is another alternative to over-tightening a hose on a badly corroded fitting.
Hose clamps should be installed about half an inch from the end of a hose, not at the very end. Position the clamp so its tightening mechanism is easy to reach, even if that may not be the “correct” position shown in your manual. Most manual illustrations were made under factory conditions when a vehicle was new and untested in actual use. Also, many connections and fittings were positioned for fast assembly rather than for easy service in the field.
Eyeball the engine for potential problems, such as ignition wires, heater hoses, fuel or oil lines fraying against something. Pay special attention to wires or hoses near exhaust manifolds. The wire or hose might look fine everywhere else, but may be stiff, brittle, or charred within an inch or so of an exhaust manifold or exhaust pipe. The same applies to areas under the vehicle. When replacing such items, always try to route them as far as possible from heat sources. Keeping fuel lines away from heat sources can also prevent vapor-lock. The fuel lines of some MUTTs frayed near the battery box cover because they weren’t mounted properly.
Get into the habit of checking the distributor point and spark plug gaps on a fairly regular basis. Also the condition of the spark plugs.
BASIC MUTT TOOL KIT
Just as important as doing these simple checks, catching problems before they happen, and fixing things before they break, is having a few basic tools aboard your MUTT.
1. Set of combination wrenches, 5/16” to 13/16”.
2. 3/8” drive socket set, 3/8” to 13/16”, including a spark plug socket. (Make sure the latter fits your waterproof plugs.)
3. 3/8” ratchet wrench.
4. 3/8” breaker-bar.
5. 3/8” socket extension 3-4” long.
6. 3/8” socket extension 6-8” long.
7. Pair of slip-joint pliers.
8. Pair of Channel-Lock type pliers.
9. Pair of wire-cutters or lineman’s pliers.
10. Pair of Vise-Grips.
11. 8” Crescent wrench.
12. 10-12” Crescent wrench.
13. Pipe wrench that opens farther than your largest Crescent wrench.
14. Three or four good screwdrivers, including a Phillips-head. (A good “four-in-one” screwdriver is also handy.)
15. Medium-sized ball-peen hammer.
16. Feeler gauge for setting spark plugs and ignition points.
17. Ignition points file (and/or some crocus cloth).
18. Pair of very small Channel-Lock pliers for working on things like the distributor.
19. Small chisel.
20. Probe-type electrical tester.
For MUTTs in daily use and/or that travel off-road, a few on-board repair, emergency, and troubleshooting may come in handy.
A roll of electrical tape. A roll of duct tape. A roll of mechanic’s wire. A roll of 14 or 12 gauge electrical wire. About six feet of 5/15” or 3/8” rubber fuel hose, plus a few mini clamps. (You can make emergency hose clamps from your wire, or nylon cable ties… another handy multi-use item.)
You should make up a pair of test leads about six feet long from 14-gauge electrical wire with alligator clips on each end, and preferably of different colors. Besides testing purposes, these leads can be used as emergency jumpers to bypass damaged wiring or hot-wire your engine if necessary. Naturally, you should always carry a good set of battery jumper cables and a fire extinguisher.
An air compressor can come in handy. Those electric types found at auto-mart stores will work on 24-volt systems if you take a lead off the “first” battery. If you’re lucky enough to find one of the ancient types that work off a vehicle’s engine, treasure it. And, always carry a tire pressure gauge, a valve core tool, and a few extra valve cores and caps. You should have at least one good-quality flashlight.
You should carry at least three road flares; and those breakdown triangles required on heavy trucks are a good safety item if you have to work on your MUTT along a freeway at night. Without question, make sure you have the proper jack and lug wrench… and know for a fact they work.
COMMON SENSE TIPS
For MUTTs that sit a lot, you should check the wiring where it’s most exposed to light. This also applies to MUTTs that are frequently driven, but in these cases you should also examine the wiring in places where it’s subject to wear from motion or vibration, and exposed to dirt, mud and road hazards.
The same goes for all rubber and flexible components, such as cooling system hoses, fan and accessory drive belts, brake lines, master and wheel cylinder seals, transmission, transfer case, and axle oil seals, and, of course, tires. These items need to be checked and/or replaced simply because of time. Because of the suspension system, MUTT tires wear faster on the outside. This can’t be compensated for by simply rotating the tires: they must be dismounted from the wheels and re-mounted with the inside out to give maximum tread life.
Batteries being overcharged – possibly due to a faulty voltage regulator – or batteries often run low by hard starting problems, may lose water faster than the battery of a show MUTT sitting in a garage. Corrosion forms on battery terminals whether or not a vehicle is in use. Battery terminals don’t have to look fuzzy or green to be corroded: corrosion also forms out of sight between the clamps and the battery posts, and the only way to detect it is remove the clamps and look. Smearing a little wheel bearing grease on the battery terminal clamps will help prevent external corrosion.
Gear oil also ages, breaks down, loses its lubricating qualities over time, and should be drained and replaced about every five years.
Engine oil doesn’t only break down and become dirty from use, it also gradually breaks down over time. And, in vehicles that aren’t driven much – or are not driven long distances so the engine never fully heats up – moisture forms in the crankcase. Moisture also forms in transmissions and differentials because of temperature changes. Water not only dilutes engine oil, it also reacts with the oil to form acids that soften and eat bearing metal. You should change the engine oil at fairly regular intervals whether or not your MUTT is driven a lot. At least once a year. Don’t forget the oil bath air cleaner, which should serviced whenever the engine oil is changed. Air cleaners may need service on a daily basis if the MUTT is used in very dusty environments.
This concept also applies to greasing a vehicle. Components such as tie-rod ends and ball joints, steering knuckles, spring shackles, and universal joints obviously need to be frequently greased on vehicles that are driven; and even more often if a vehicle is used off-road. Just like changing the engine oil, the oil filter, and servicing the air cleaner, grease is one of the cheapest forms of insurance against a vehicle breaking down. Most things break because of wear; and clean, good-quality lubricants replaced often and maintained at their proper levels considerably slow the wearing process.
Keeping your MUTT safe and dependable also includes mundane items like windshield wiper blades. The time to discover they’re hard or rotten and won’t clear the glass is at home, not during thunderstorm out on the road.
By now, it should be obvious that MUTTs that sit for long periods need regular inspection and maintenance just as much as daily-drivers. All of a vehicle’s moving parts, whether in the engine, transmission and axles, wheel bearings, steering and brake systems, are constantly being polished during use and kept clean and free by their various lubricants.
When a vehicle is sitting, oil drains away from piston rings, rocker arms, timing chains and transmission gears. In addition, ferrous metal rusts, while copper wiring and brass electrical contacts in voltage regulators, terminals and switches oxidize and corrode. Gasoline loses its volatile hydrocarbons and goes flat, forming varnish and sludge in fuel tanks, lines, pumps and carburetors.
Another hazard to vehicles that sit is the insulation on their wiring can be gnawed by rats and mice. Rubber parts dry out, shrink and crack, in everything from windshield stripping to the internal parts of vacuum windshield wiper motors. Products such as Armor-All will protect the former. Removing the hoses and spraying something like WD-40 into vacuum wiper motors while working their manual handles will keep them operating smoothly.
Tires contain oil that is continually being brought to the surface while rolling and flexing. When sitting, tires dry out and rot, and may become unsafe even if they still look good. Tires may also develop flat spots on the bottom, which may not roll out when the vehicle is driven. All these things should be checked, serviced, or repaired or replaced at regular intervals no matter how little your MUTT is used.
In current vernacular, “dog” is a complimentary tag for a faithful friend. Your MUTT should be no less faithful.