Overdrive Magazine | Trucking Business News & Owner Operator Info
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EquipmEnt 42 | Overdrive | June 2014 By Jack Roberts Hoses and belts How to avoid premature failure and maximize the life of these flexible parts Compared to the chemistry set required to test a truck's coolant mix, checking the hoses and fittings in the cooling system is a relative snap. Your primary diagnostic tools are with you all the time: your hands. "Coolant hoses degrade from the inside out," says Frank Burrow, manager of warranty and customer support at Red Dot, a supplier of A/C systems and components for heavy-duty vehicles and off-highway equipment. "At a glance, there's rarely an obvious sign of wear and tear. Palpating a coolant hose is one of the simplest ways to gauge its condition." Hose deterioration is caused by an electrochemical reaction between the coolant and metals in the system, such as steel clamps, a copper heater core or a cast-iron head. Tiny cracks develop in the tubing, typically near the hose ends, allowing coolant to reach and cause wear to the reinforce- ment yam. As the hose degrades, it sheds debris into the coolant. "You have foreign material circulating through the heater core," Burrow says. Any places the hoses or fittings are fastened, clamped, connected, bent or otherwise secured are potential wear points. The same goes for places where hoses are not clamped or sup- ported but should be. Follow these tips to get long life from coolant hoses: INSTALL HOSES PROPERLY. Consider the hose's natural curl as it's un- spooled from the reel. Coolant hose should be installed so the bend is in the most relaxed position, not pulling away from the fitting. "That load, however slight, is an opportunity for pressure to build and a weak spot to form," Burrow says. USE CLAMPS THAT PROVIDE UNI- FORM PRESSURE. There can be as many as 50 hose-clamp applications on a heavy-duty vehicle, as well as a variety of different clamping systems. For the cooling system hoses, consider the hose type, size and material in choosing clamps that provide uniform tension and sealing, especially in low temperatures. CONSIDER USING TORQUE-SPECIFIC CLAMPS. Some clamping systems have specific torque ratings and require special tools for installation and removal. While screw-type clamps are simple and easy to find, more com- plex torque-specific clamps aren't as susceptible to overtightening and do T ruck engines are hellish environments, so overlooking belts and hoses is an invita- tion to disaster. Since good maintenance is no guarantee against premature fail- ure, knowledgeable technicians know to change out belts or hoses if even a hint of trouble is spotted. Away from the shop, your best preventive maintenance is to target belts and hoses during pre-trip inspections to spot potential problems. Due to an electrochemical reaction at weak points of coolant hoses, they tend to deteriorate from the inside out, shedding material into the liquid. How to maintain hoses HowTo_Belts_and_Hoses.indd 42 6/3/14 10:21 AM