08Brake Inspections Tech Tip130007032019

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 Experts also note to be careful about the turning process, otherwise the drum may be damaged. “When the drum is installed on the hub it is very important to make sure the run-out is within industry standards,” Kay says. “The objective is to have no run-out. Run-out can lead to reduced brake performance, component damage, and Vehicle Noise Vibration Harshness (NVH), which is irritating to the operator. “The drum surface needs to be smooth,” he adds. “A rough surface can lead to reduced brake performance. If the machining lead is too large it will cause the brake shoe to move axially causing popping noise. It’s like a record player following the groove on a record. When the shoe gets to a hard contact point it jumps back to center and it makes a loud popping noise.” Improper turning techniques aren’t the only problem with drum turning. Just keeping up with drum specs can be a challenge. “The problem I find is that most techs do not know at what measurement the drum is no longer usable,” Pfost says. “But techs tell me this isn’t something they need to know because they replace drums at every friction change.” With so many training opportunities offered in a range of venues, it’s hard not to stay up on best practices. Meritor offers free training manuals online at meritorbullpen.com . Training videos are also available along with dozens of courses. “This is a comprehensive web-based training platform offering more than 100 courses designed to enhance the product knowledge and service needs of technicians, dealer and aftermarket sales professionals, drivers and warranty administrators,” Kay says. Despite the benefits of improving safety, productivity and avoiding costly violations, training can still be a challenge with some service departments. “Yes, I think techs understand what a severe out of service drum looks like,” Pfost says. “If they see a crack in the drum — or severe scoring or grooving — it will be changed out. I do question whether they understand the out of service criteria of 0.120-in. over the original drum diameter. I hear from techs that the lip on the drum does not feel too deep. I then share that if the measurement exceeds .060-in. from the top of the lip to surface of the drum, the drum is out of service. Basically, .060-in. is equal to 2/32- or 1/16-in. To make sure they understand this I ask, ‘If they feel a lip on the drum is it or is it not out of service?’ I’m trying to drive home that they cannot tell simply by feeling the lip.” While best practices in the shop are critical in maintaining healthy brakes, experts adds drivers also can do their part by avoiding certain habits that can lead to premature drum wear. “Overloading the vehicle, aggressive driving and a lot of hard braking,” Hasinec says. “The wrong friction material for the application can cause this also. Extensive hard braking and panic stops can crack (the drum) all the way to the outer shell and in some cases cause the drum to shatter. Premature wear can actually be normal wear in some cases, due to the duty cycle/application of the vehicle.” June 28, 2019 (08Brake Inspections Tech Tip) Relined in the USA! MAXIMUM HEAVY DUTY BRAKES Ask about our MAX HD Brake Stop Boxes High Quality Brake hardware is included in the box to insure your MAX HD Brake reline gives you maximum life and performance to your wheel end. We offer RSD Lining from Abex & Bendix QUALITY CONTROL - PERFECT FIT TO THE SHOE TABLE AND BRAKE DRUM