Surface rust removal, tie to tow, sniffing your dipstick and more in this installment of Tech Tips

I use plain old brown cooking vinegar from the supermarket. Drop the rusted parts in it for a few days, and all the rust is removed (not converted, like phosphoric acid), back to a shiny bright surface. Dirt on the item to be stripped is ok, as long as it isn’t oily dirt — it will be stripped once you wash the dirt off. Dip in bicarb of soda to neutralize the vinegar, wash thoroughly, dry and primer it. Molasses diluted 1:4 also works fine. No need to use other fancier acids. I used brown vinegar as it was a few cents cheaper per bottle than white vinegar, which works just as well. After use, filter it and pour it back into the container for next time. — Steve Malikoff Sydney, Australia

In most cases you should not tie the steering wheel when flat-towing a vehicle. If you do, the towed vehicle won’t willingly follow the towing vehicle around sharp turns or into gas stations and parking lots but will only skid and drag its front wheels. If you watch a vehicle being flat-towed, you’ll see its steering wheel turns and it wants to follow the towing vehicle. Tying down the steering wheel used to be common practice among tow truck drivers, but this was usually done to hold the front wheels in a straight-ahead position when hooking up or loading a vehicle or lifting its front end off the ground. Once in a while you might encounter a situation where the towed vehicle just won’t behave and you will have to tie down the steering wheel. This is often the case when towing an engineless vehicle that doesn’t have enough weight on its front end to track properly. Jeeps seem to like being towed and usually mind their manners. In short, never tie down a steering wheel unless you have to.

Get into the habit of sniffing your dipstick every time you check your engine’s oil level. This is a good way to check the oil’s condition. Sniffing can tip you off to various mechanical problems. You may have heard that automatic transmission fluid should never smell burned. This is also true for engine oil. A burned smell means your engine is running too hot and/or the oil has been in service too long... whether or not it still looks clean. This also applies to the fluid in your power steering system, as well as the hydraulic oil in your dump truck or wrecker. Not only should your engine oil never smell burned, but an odor of gasoline usually indicates that your carburetor float or needle valve is sticking and letting raw gas into the cylinders, or that your mechanical fuel pump diaphragm is ruptured or leaking, letting gas drain into the crankcase.

Vehicle cooling system hoses must withstand heat, pressure and vibration. They’re rubber, so they rot, harden and crack with age. That’s why you need both your eyes and hands to detect bad or failing hoses. Bad hoses are puffy, hard, mushy, or wet. Also check the radiator. Look for leaks on the top tank, and on the front and back of the core and bottom tank. Leaks may not show up when your engine is cold, so look for rust and odd-colored dribbles where coolant has leaked and dried. Later, when you’ve got the engine running at operating temperature, check those places again for wet spots. Finally, take the radiator cap off — carefully. If the cooling system is hot, open the filler cap slowly until all pressure is gone. Be sure to use a rag or glove to protect your bare hand from a hot cap or hot coolant. The coolant should be a little over the top of the core. It should be almost clear and colored by the antifreeze. If the coolant is muddy or has bits of gunk in it, Our cooling system needs draining and flushing. If you see a rainbow of oil slime on top of the coolant, you probably have a leak inside the engine. Exhaust gas or oil is getting into the cooling system. Pull the crankcase dipstick and check for water in the oil.

A: Five-quarter fuel tanks are known for rusting and leaking, but you have many options. If you want to keep your truck stock, you could contact various advertisers in this magazine who offer M715 parts to see if they have an NOS or a good used tank. Depending upon the condition of your present tank, you could investigate various means of repair, including coatings touted as being able to seal leaking or rusted tanks. You could also search through truck wrecking yards to possibly find a tank that could be modified to fit. Or, if money is no object, you could have a tank custom built.

A: First off, if you don’t have the service manual for your HMMWV, you should get it. Many early model HMMWVs had problems with the front CTIS air line hoses because they were too short and had improper stye fittings, so making a sharp turn strained them. Take some dish-washing soap mixed with water, squirt it around the front hubs and CTIS hoses. Bubbles will reveal leaks. I suspect your hoses will need replacement after you install the new style fittings. 

Send your favorite Tech Tip or question to Steve Turchet at military@aimmedia.com

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