Issue link: http://read.dmtmag.com/i/29112
5 cover and reinstalling with a new gasket. This should be attempted only by someone with mechani- cal experience. On Mack trucks, grease the two grease points every 4,000 miles in off-road service, 15,000 on-road. Check the inter- val on other brands. 6 8 Also on tandem suspensions, inspect the spring isolators or 8 “elephant pads” to make sure they are not cracked or crushed. Have them replaced if deteriorated. Truckers News thanks Carl Smires, service advisor, and Brad Galla, technician, of Pennsylvania Truck Centers in York, Pa., for their help with this article. 7 6 7 BIG RIG BASICS TIP “A critical main- ten ance item is the center bushing made of vulcanized rubber. You can tell when it’s starting to fail as the dog-bone-shaped center rocker will start to move out so the weight is no longer springs before wear causes further damage. Inspect all multiple spring arrangements for broken or cracked leaves and replace broken/ cracked parts. On tandem suspensions such as the Mack Camel- back, inspect the trunnion bear- ing, which allows the tandems to rock. This requires removing the 32 TRUCKERS NEWS MAY 2011 on center but is cantilevered. Replace the entire unit if the bushing fails. It makes a better repair because the wear can make the hole egg-shaped. The entire assembly just bolts in place — much easier than pressing in a new bushing. Inspect and, if worn or damaged, replace the pins that are located under the springs and keep everything in place during rebound.” — BOB MADDOX, NICK AND DEE’S TRUCKING, HEREFORD, TEXAS