Bendix Tech Tips: Auto Slack Adjuster Maintenance


Source: Bendix announcement

ELYRIA, Ohio –– Time and miles: both seem to roll by more quickly than we realize. Consider six months, 1,800 operating hours, or 50,000 miles – for many working trucks and truck drivers, those aren’t long intervals, but they are key markers for a piece of basic wheel-end preventive maintenance that is too often overlooked. This installment of the Bendix Tech Tips series reviews greasing automatic slack adjusters (ASAs), the importance of keeping up with their regular lubrication schedule, and other related wheel-end practices to enhance uptime and safety.

Dual-Purpose PM

“There are two vital purposes to greasing an automatic slack adjuster,” said Keith McComsey, director of marketing and customer solutions, Wheel-End. “First, it protects the adjuster’s internal gear sets, clutches, and other components from premature wear. Second, the action of forcing new lubricant into the ASA purges the old grease, along with any contaminants or water that have found their way in. Both support vehicle safety by maintaining the correct brake stroke and providing optimal stopping performance.”

It is not uncommon for Bendix technicians to encounter automatic slack adjusters that have not been greased regularly. Neglecting this simple bit of maintenance leads to the grease inside an ASA becoming clay-like as it accumulates contaminants and loses its ability to lubricate the slack. In addition to impeding performance, by impacting the brake stroke, this condition can put a vehicle out of compliance with stroke regulations. Fortunately, it’s easily avoidable.

Related post:
Bendix Tech Tips: Upkeep of Steering Gears

The American Trucking Associations’ Technology & Maintenance Council’s (TMC) recommended practice (RP) for greasing ASAs lines up with those interval numbers mentioned earlier: Every six months, 1,800 operating hours, or 50,000 miles, whichever comes first. And lubrication is a simple process that generally takes less than one minute per adjuster.

Easy as 1-2-3

Begin by locating the ASA’s grease fitting.

This will vary depending on the make of the adjuster: On a Bendix® Versajust®, you’ll find it on the slack adjuster body (casting); on others it’s a hole in the casting.

Next, attach the hose from a grease gun, and inject new grease until old grease is forced through the release opening. Follow manufacturer’s instructions on how much grease to purge from the adjuster and what lubricant to use. Seriously:

That’s it.

The entire Tech Tip can be viewed by clicking HERE.

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