Maintenance Q&A – March/April 2021

Q. I had a full brake job done last year on my 2016 Pete. When I took it in for a regular oil change last week, my mechanic told me that I need to get a new set of brakes because the government changed the regulations on brake shoes and mine are out of compliance. Is this correct? Do I have to spend additional money, or is my shop just trying to grab my wallet?

A. This seems to be as much a regulatory question as a maintenance one, so I checked with the Technology and Maintenance Council. Robert Braswell, TMC executive director, told me that the tech probably misinterpreted what he had heard. Here’s the story.

There have been environmental problems with brake linings because the very nature of brake wear puts the microscopic particulate matter into the environment. The Environmental Protection Agency reached an agreement with several western states to reduce the amount of copper to less than 5% by weight by 2021 and 0.5% by 2025. Copper had been used to replace asbestos and conduct heat created by friction. Other toxic metals were also covered, including mercury, lead, cadmium, chromium salts and asbestiform fibers. Once worn from brake pads, these particles settle and are washed by rain and snow into the nation’s waterways. They affect fish, amphibians and plants, and our food supply. In 2010, about 1.3 million pounds of copper went into California’s environment, with an additional 200,000 pounds into the state of Washington. Improvement to date reduced the amount of copper by 61%.

These changes are directed to manufacturers.

The EPA does not have the power to regulate over-the-road vehicles once they are manufactured.

Even the National Highway Safety Administration does not have the power to make you replace your brakes. They can only affect original equipment manufacturer and aftermarket parts.

While your tech was correct in learning that new brake friction material formulations went into effect this year, he was wrong in assuming that they require you to replace your brakes now. When you have your next regular brake job, you will receive the new formulation.

Q. I’ve got a 2015 Mack with a dump body that I use mostly on construction runs in warm weather. In the winter, I haul salt and sand for municipal snow-clearing operations. Lately, I’ve been losing coolant, but there are no signs of leaks. I checked the hoses, the radiator and fittings. Everything seems to be good. Any idea what the problem could be?

A. For cooling system questions, I referred first to the TMC Recommended Practices Manual RP313, Checklist for Cooling System Maintenance. It has a comprehensive list of items to be checked. Based on what you told me, I would suspect one of several problem areas: hose condition, hose clamps or the radiator pressure cap.

Hoses can feel structurally solid with the engine off, due to pressure built up in the system. Hoses could be damaged on the inside without showing outward signs, but when operating there could be micro-cracks that allow coolant to seep out. Water, being less viscous than glycol, will permeate through the hoses first and quickly evaporate. This could be due to contamination of the coolant or an electrochemical reaction if there is stray voltage through the engine block. This is most prominent when dissimilar metals are used for system components, such as brass or aluminum radiators, and iron cylinders. It’s worse if there is a stray ground current.

The metals act like a battery with the coolant being the electrolyte. This can deteriorate attachment points and promote leaks.

One way to test if it is permeation or electrolytic deterioration is by testing the coolant for concentration. The ideal concentration is a 50/50 mix of glycol and water that will show a freeze point of minus 34 degrees F for ethylene glycol and minus 27 degrees for propylene glycol. If the freezing points are significantly below these values water has permeated the hose to a greater degree than the glycol, lowering the freezing point further below zero. If the freeze point is at the recommended levels, you can probably rule out coolant loss through the hose.

When checking hoses don’t forget those leading to cab heater cores or supplemental coolers, if so equipped. If hoses are suspect, it’s a good idea to replace all of them, because one damaged hose may be an indication of deterioration of all the others.

Check fittings and clamps. They can be the source of slow leakage and coolant evaporation. Radiator fittings may have worn so they are too weak to resist clamp pressures. Hose clamps can exert uneven stresses in fittings. Clamps should be band-type providing full, 360-degree contact. Some shops cut costs by using heavy wire clamps. These exert pressure on a single line of contact rather than a broad surface. Avoid screw-type hose clamps without underlying protective bases. They allow rubber to extrude through their slots, weakening and degrading the hose, especially if using silicone hoses. They are more easily extruded through these clamps.

Heat shrink polymer bands work well but cannot be reused.

The best are Oetiker-type clamps. They provide wide, even contact and temperature compensation for even pressure at cold starts and during operations.

The radiator pressure cap is a frequent cause of coolant loss. The cap, usually calibrated to open at 15 psi, allows pressure to build in the cooling system. This pressure raises the boiling point of water to about 250 degrees. Over time pressure springs can weaken and seals can leak or the seat can be damaged, all of which reduce the pressure and therefore the safety factor for coolant. Some imported pressure caps do not meet the design specifications. They can leak prematurely, causing coolant to leak and evaporate.

All these can result in coolant loss without leaving pools of coolant in the parking lot or signs of leakage around the fittings. LL