No matter how religious a shop is with preventative maintenance (PM), brake systems will eventually have to be replaced. Randy Petresh, vice president of technical services for Haldex Brakes, says the problem with brakes and tires is fleets are constantly wearing them out, so replacement...
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No matter how religious a shop is with preventative maintenance (PM), brake systems will eventually have to be replaced.
Randy Petresh, vice president of technical services for Haldex Brakes, says the problem with brakes and tires is fleets are constantly wearing them out, so replacement becomes a high maintenance expense.
When the maintenance issue does come down to replacement, Chuck Eberling, principle engineer in vehicle systems group for Bendix Commercial Vehicle Systems, warns technicians to follow the original specifications for the brake systems as possible.
"As far as lining and component replacement, you want to be certain-and all of Bendix's manuals state this-that mechanics are replacing like for like with respect to foundation brake material being utilized for a given application," he says.
Tom Runels, manager for drum brakes for Bendix Spicer Foundation Brake, persuades technicians to constantly refer back to the manuals for specific component indications.
"Our expectation would be that the OEM equivalent materials would be used, whether it is linings or bearings, air chambers-anything that would be replaced on the brake would be OE equivalent-otherwise they are not within the approved specification," he says.
Kurt Hornicek, director of medium heavy vehicle technical services for ASE, says "Our policy here at ASE is that whatever the OEM or component manufacturers recommend during any type of repair or diagnostic procedure, that's our standing," he says.
Mike Caggiano, product line director for specialty products at Bendix Spicer Foundation Brake, said that although a brake system can still function if individual components are replaced rather than the entire system, it isn't ideal.
"In a perfect world, when you go in and do a brake job, you would change all the parts. It's getting it as close to the original equipment as possible. Go in and replace everything, however na?ve that may be," he says.
"We recommend that they change brake shoes, springs, pins and clips, (and) if you are going to change the drums you look at your bearings, your seal and all of those types of things," Caggiano continues. "Slack adjusters and spring brakes, while they are wheel end-related, they don't normally need to be changed with every brake job-they are looked at a little bit differently, they are a little bit outside of the normal wear items."
Hornicek reminds technicians that they need to know what to look for. "Brakes are still the number one issue year in and year out," he says.
"Check to see if the automatic slack adjusters are properly maintained. If they are not maintained properly, then the brake will go out of adjustment," he says.
Hornicek advises that there are various ways to check brakes. "One, make sure the brake is in adjustment. If it isn't, let's say you do a brake job including the initial set up, you've got to just make sure that the brake is set up properly," he says. "It really depends upon the manufacturer you use."
Preventative maintenance for brakes is unlike other components where technicians can use diagnostic tools to find the trouble codes.
According to Hornicek, "Most brake inspection is visual. If you are doing an initial installation, for example, you put on a set of shoes, there used to be one where you did a torque wrench and torque check on it to see if it would move. It is pretty bullet-proof overall," he says.
"So when you are looking at maintenance, you do the same thing to the right side as you do to the left side, and you change everything out at once," Caggiano says. "Although we all know in practice, that doesn't happen."
"We would ask that if they change shoes or pads then they change the related hardware. Brake systems are designed to be fault tolerant and extremely reliable under such diverse conditions and lots of levels of maintenance. Maybe that's why the industry doesn't maintain things as well as they really should because they have found that they get reasonably reliable performance when they sometimes run a little short on their maintenance calls," says Caggiano.
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