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Wednesday, September 23, 2015

Your mechanics may be doing more harm than good when it comes to brake maintenance

michiganautolaw.com
Article thanks to Jordan Fullerton of Pacific Fleet Inspections LLC. Links provided:
Sept. 3, 2015  This is the follow up that I promised in my last post on brake inspections.
Out of adjustment brakes are the top brake violation found by Pacific Fleet Inspections LLC (along with most DOT inspectors). There are two main points that I'd like to cover:
1) AUTOMATIC SLACK ADJUSTERS SHOULD NOT BE MANUALLY ADJUSTED:
After countless hours of researching brake manufactures data sheets on the topic of air brakes, it's clear from the research that automatic slack adjusters  (ASAs) should NOT be manually adjusted by a mechanic (or driver) except:
  • By a qualified technician and only upon initial installation
OR
  • When absolutely necessary to move the vehicle to a nearby repair facility.
If the slack adjuster becomes out of adjustment it is most often a result of one or more components that have deteriorated and should be replaced, eg,. S-cam, S-cam bushings, slack adjuster, control arm, rollers, brake drum.
Excessive manual adjustments by mechanics and drivers can rapidly deterioratethe integrity of the ASA thus causing more frequent out of adjustment brakes. So what's a mechanic to do as far as regular slack adjuster maintenance goes? The manufactures recommend that regular greasing, thoroughly inspecting and replacing defective components are it; the automatic slack adjusters will do the rest.
2) IN-CAB SLACK ADJUSTMENTS
Automatic slack adjusters are designed to stay in adjustment every time the brake pedal is firmly pressed. To see a clear demonstration of this watch 90 seconds of this YouTube video put out by Haldex (start at the 13:25 minute mark).
You'll notice 2 things in the video. First, upon each brake application, the slack adjuster takes up the slack (intentionally put there by the mechanic for this demonstration). And secondly, a truck driver can perform this procedure each time they perform their pre-trip inspection to ensure their brakes are in adjustment.
FURTHER READING:
Manual Adjustment of Automatic Slack Adjusters May Contribute to Unexpected Brake Failure on Automotive Fire Apparatus

Pennsylvania Runaway Truck Accident Reveals Dangers of Manual Adjustments to Automatic Slack Adjusters, NTSB Finds

FOR MORE INFORMATION OR TO SCHEDULE A FREE CONSULTATION & BRAKE INSPECTION:
Call: 503-341-3384 - Jordan


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