08Meritor Brake TechTip130008062019

TECH Tips How About a Little More Brake and a Little Less Shake? Today’s RSD (Reduced Stopping Distance) compliant vehicle steer axles, with their increased size and torque, are more susceptible than prior vehicles to braking vibration issues due to assembled brake TIR (Total Indicator Reading). Three major factors contribute to assembled brake TIR; drum run-out, hub-to- drum mating surfaces/pilots and wheel bearing adjustment. You must check TIR on a brake drum in an assembled brake. Do not disassemble the wheel/tire assembly, brake drum from hub or any other components prior to initial TIR inspection. Disassembly will change the original position of the assembled components and may vary TIR readings/performance. If assembled TIR exceeds 0.015-inch (0.381 mm): • • Remove the drum and inspect the components. Damaged and corroded hub-to-drum mating surfaces/pilots are becoming a common cause of vibration complaints. • • Verify wheel bearing adjustment. Wheel bearing end play must be within the required 0.001”-0.005” or be properly preloaded with Dr. Preload or assemble brake TIR will be increased. Excessive end play can cause the drum braking surface to not be concentric to the bearings/spindle. If damaged is found, replace the necessary components, re-assemble and verify TIR is within specification IMPORTANT: For proper brake balance and performance: • • Verify that all brake drum diameters on an axle are within 0.025’ • • Verify all brake drums are under 0.080’ of wear, allowing for wear during current service interval • • Verify brake drums are all of equal original weight • • Verify that the original Brake drum weight is proper to dissipate the heat generated by this brake in the current application MIDWESTWHEEL.COM IOWA MISSOURI DES MOINES 1436 E. Ovid Ave. office 515.265.1491 fax 515.265.4120 parts fax 800.314.4329 parts 800.888.0248 CEDAR RAPIDS 200 50th Ave. S.W. main 319.365.4453 fax 319.365.6327 parts fax 877.706.6085 parts 800.332.5435 DAVENPORT 8502 Northwest Blvd. main 563.322.2671 fax 563.322.5940 parts 800.553.1886 SIOUX CITY 1819 E. 4th St. main 712.252.7969 fax 712.252.6149 parts 800.943.3534 CLEAR LAKE 840 Hwy. 18 W. main 641.357.7101 fax 641.357.8190 parts fax 800.548.9674 parts 800.397.5630 KANSAS CITY 5801 E. Front St. main 816.471.1552 fax 816.471.0813 parts 800.821.7402 TRUCK PARTS SUPER STORE TM August 6, 2019 (08Meritor Brake TechTip) CATALOG NUMBER 08 www.midwestwheel.com Order NLINE ™ www.midwestwheel.com Order NLINE ™