Issue link: https://read.dmtmag.com/i/34500
VALVE SYSTEMS Always replace the whole valve assembly when a new tire is mounted. Ensure the valve stem is installed using the proper torque value: 80 to 125 in/lbs (7 to 11 ft/lbs) for aluminum wheels and 35 to 55 in/lbs (3 to 5 ft/lbs) for tubeless steel wheels. When an aluminum wheel is used in the outset position, a TR543E or TR553E valve degree bend can be used. This valve has a 75-degree bend that facilitates taking air pressures. If the valve stem is installed on the inboard side of the wheel, ensure proper clearance exists between the brake drum and the valve stem. It is highly recommended that the older style valve stems be replaced with the newer style TR553E to minimize corrosion build-up, thereby minimizing stem leaks. Per TMC RP 234, Proper Valve Hardware Selection Guidelines it is recommended that an anti-corrosive or dielectric compound be used on the valve stem threads and O-rings prior to installation. This will prevent corrosion from growing around the O-ring, which squeezes it and causes leaks. Check with your aluminum wheel manufacturer or valve stem supplier for their recommendation of an anti- corrosive compound. Corrosion Related Leak TR553E Valve (left) and TR543E (right) When installed in the inset position, the longer TR545E valve is required. Note Corrosion On Bottom Valve TR545E Valve If the operator uses the wheel as a step when securing the load, a straight TR542 valve may be preferable. An angle head pressure gauge will be required to check air pressure, but it may still be difficult due to interference with the hub. Checking for loose and leaky valve stems should be made a part of your regular maintenance schedule. Methods for checking for loose valve stems are: – check with a torque wrench, – check by hand to see if the valve nut is loose, – spray a soapy solution on the valve to see if there is a leak. To protect the valve from dirt and moisture, a heat resistant metal valve cap with a rubber seal must be installed. The number one cause of air loss in tires can be attributed to missing valve caps. To facilitate air TR542 Valve pressure mainte- nance, a dual seal metal flow through cap may be used instead of a valve cap. These should be installed hand tight only to pre- vent damaging the seal (1.5 - 3 in/lbs). Valve Cap With Rubber Seal Dual Seal Metal Flow-Through Cap Tire and Wheel Nomenclature 5