Tech Tips: Storage systems and going into the deep

I’ve been hearing that same thing ever since I was a kid, but, back when I was around 13, a wise old mechanic told me to use Copper-Coat gasket sealer on head gaskets. I’ve been following his advice ever since, and I’ve never had a gasket leak or blow yet, even on engines that were frequently blowing head gaskets. I use plenty of the stuff on both sides of the gasket and shake the can often to keep the copper in suspension.

I must have tried just about every “storage system” known to civilized man for the various small parts and spare items I keep aboard my Nissan Patrol. However, most store-bought storage units never seemed to be just the right size or able to hold what I wanted to put into them. Then I started using various sizes and shapes of cookie and candy tins, ranging from small tins used for cough drops on up to those used for square or rectangular cakes. This has proved to be the best system for me. It seems that no matter what I want to store, from spare valve cores and light bulbs to distributor caps and tune-up parts, I can always find a tin that’s just the right size and will fit where I want it to go in my truck. You can always paint the tins olive drab or black if their cheerful colors and cute designs seem to clash with your military vehicle’s (or your) rugged persona.

A more accurate description would be “water-resistant vehicles,” just as many watches are advertised as being “water-resistant” as opposed to “waterproof.” The same would apply to all M-series vehicles, not just the HMMWV. Even if fitted with a fording kit, driving a vehicle under deep water is considered to be a last-resort event. It’s a very stressful ordeal for the vehicle and meant to be over with as soon as possible. In spite of sealed dashboard instruments, lights, and switches, as well as special gaskets and 0-rings on air-cleaners, carburetors, starters and generators/alternators, the majority of seals and gaskets on M-series vehicles’ engines, transmissions, transfer cases, and axles are of the conventional type. They’re designed to keep oil and other fluids from leaking out, not to prevent water from leaking in. In other words, these gaskets are meant to withstand pressure from within, not from without. In addition, the special seals and gaskets on M-series vehicles, including the battery caps, are not intended to withstand being submerged for long periods of time. Simply put, there are just too many places for a vehicle to leak. If an M-Series vehicle were parked under deep water for any length of time, one would likely find its engine, transmission, transfer case, and axles, as well as its batteries, and possibly its fuel tank and starter, full of waterwhen one attempted to start it.

The best precaution would be not to do it. Most smart people who drive off-road or out in the bush, and who don’t have breakdowns or get stuck, adopt the philosophy of “do I really need to go there” before attempting to climb a mountain or cross a river. Aside from asking yourself that question, as well as reading the tech tip above, you should get a manual that covers the procedures for deep-water fording your jeep. Understand that driving any vehicle under deep water is not a casual event. It requires considerable preparation, as well as service after the fact, such as checking the engine, transmission, transfer case, axles, batteries, fuel tank, and brake master cylinder for water when you’re back on dry land. Also, keep in mind that just because you recently installed a, fording kit, that’s no guarantee that the seals, gaskets, and 0-rings on your vintage vehicle are good enough to withstand deep water pressure. If, in spite of my advice, you want to go ahead with this adventure, you should have another vehicle standing by that is capable of rescuing your Jeep from Davy Jones’ locker. Also, be sure to remove the fan belt because water is not compressible, and the fan blades may be bent forward and cut into the radiator from trying to pull water instead of air.

I have one in my Nissan Patrol; and yes they work. But, like most vehicle components or accessories, you should understand their intended purpose and know how to use them properly. Just as fog lamps are meant for fog, and, as a bush pilot friend of mine once said, “Landing lights are for landing,” the Mico Brake Lock has a specific purpose and should not be misused. The kit you describe is basically a lever-operated valve that installs in your brake system with additional’ tubing (not included). Operation is simple: After stepping on the brake pedal to apply the vehicle’s service brakes, you then flip the lever, which traps brake fluid under pressure in the system. This keeps the service brakes on. Mico also offeres a kit with an electrically-operated solenoid valve and a toggle switch that took the place of the manual lever. However, the Mico Brake was never intended to be used for long periods of time, just as the wheel cylinders on most vehicles were not designed to hold pressure for hours on end. The Mico Brake Lock is a very handy device in off-road situations on steep slopes when you need to hold the vehicle with the engine running and the stock parking brake is not sufficient. It’s also handy in the city to hold a vehicle on a hill while waiting for a stop light to change. The Mico is often used on commercial vehicles that need to be held in place while their engines were running. However, the Mico was not intended to replace a vehicle’s stock mechanical parking brake, and leaving it locked for long periods will cause the wheel cylinders to leak.

Try working on your M3Ts engine on a windy day with the hood raised all the way back against the windshield and the purpose of that little rod may become painfully apparent!

Should we be charging foreign terrorists for this information?

I’d say that depends upon how you use your M37. Those gear sets are well worth the price if most of your driving is on-highway. One used to be able to find complete third-members (or “pumpkins”) in wrecking yards from Dodge 1-ton civilian trucks that would replace the units in M37s and allow a comfortable cruising speed of 55 mph. This, I believe, is about what the conversion kits offer. You do lose some on-highway power, though I had the aforementioned pumpkins in an M37 and liked them very much. Then, too, since you have higher-speed axles, you can get better speed from all the transmission gears. So, even if you have to shift down on steep hills, you can still go faster. Off-road performance is not affected much because you have a low range in the transfer case. Although I don’t know about the new kits, the old civilian pumpkins were smaller and slightly weaker than the M37s original units. This might be something to consider if you use your truck for heavy hauling or in severe off-road conditions.

Yes. However, you would lose some power, and the truck would be more prone to breaking axle shafts under severe off-road stress.

I suspect you are indeed on the right track. It sounds like the carburetor is flooding on the steep grades. You should also see some black exhaust smoke when this happens. My best guess would be that the float level is set a little too high so the bowl overfills when at a steep angle. If this is the case, then it would happen no matter what type of needle valve you have. Try lowering the float level a bit and this may solve the problem. As to the best type of needle valve, the Viton type usually seals better, but the OEM original type with the little spring was designed for rough service and may help prevent the problems you’re having.

Do you know for certain that it’s indeed the rear wheels that are binding and not the front? The front wheels binding might indicate an engaged, jammed, or improperly adjusted sprag unit in the transfer case. Unlike a full-air system with spring-loaded parking brakes, the M135 has only an air-over-hydraulic booster, so you don’t need air in the system (or the engine running) to release the brakes. Since you removed both rear drive shafts, you can eliminate a jammed or frozen transfer case and parking brake as the cause. So, if the truck has been sitting a long time, your problem is possibly rusted or jammed brake shoes. The simplest thing to do would be to jack each set of wheels off the ground and try to turn them by hand. Rusted or jammed brake shoes would be obvious by their scraping sounds against the brake drums; in which case, backing off the adjusters should help. If jammed brakes don’t seem to be the problem, I would suggest pulling the axle shaft that goes to the “sticky” set (or sets) of wheels. It is very unlikely that the wheel bearings are frozen unless the truck sat in deep water for some time.