auto brake adjusters

never heard of it either. but illegal or not. i'm still adjusting. cuz i sure don't want to be put OOS.

and auto adjusters DO go out all the time. unless they are lubed every week.

most trucks only get lubed when it's time to change the oil.

 

According to the FMCSA, you need to be qualified to adjust any truck/trailer brake: http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?reg=396.25 Some companies train their drivers and give them a little laminated card.

As part of getting your CDL with air-brake endorsement, you are only qualified to inspect your brakes.

 

like i said. certified or not. i'm adjusting.

if my brake gauge go higher then normal. i know something is out of adjustment. and i don't drive with loose brakes.


you get inspect3ed. they don't ask if your certified. they only look for that precious travel.

 

Oh, he's wrong. You can do damage to some types of slack adjusters (Meritor?) by doing the standard crank them down till contact, then back off, but that's only if you forget to first disengage the pawl.

But most of the time I spot an automatic slack adjuster out of adjustment, I can make it adjust by pumping the brake enough to trigger the 60psi buzzer.

 

Certified and qualified are two different things.

The FMCSA link posted above paints a very grey picture. But points towards them wanting some sort of paper trail that shows the person knows what they are doing.

Many certified people are not qualified. Many qualified people are not certified.

Essentially, as long as you know what you are doing, theyll most likely never ask unless there is an accident that is determined to be brake related. Then theyll come sniffing.

Now of its not your truck, then check the company policies. Make their mechanics adjust them. If they claim they cant and your brakes are out of adjustment, I guess theyll be spending extra money. But thats their issue.

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As a newby, how does one tell the brakes are out of adjustment? It would appear that if double yellow is correct, if the brake portion of the daily pre-trip inspection is performed it would reset/adjust the brakes.

 

The problem is that you typically don't do low-air warning checks everytime you drop & hook throughout the day (if you even do it daily -- I probably do it weekly). And even if you were to do it every d&h, you still can have some malfunction/corrosion which prevents the adjusters from working automatically (particularly if your company has old equipment).

As for brake inspection, it should be part of your walk-around before driving off with a new trailer. My personal trailer pre-trip check is as follows:

1) Before hooking, walk around trailer looking for obvious damage, flat tires, seal on doors, etc. During this walk around, observe the angle between the brake's slack adjuster and the pushrod -- the angle should be about the same at all 4 brakes and since the spring brakes are currently applied, that angle should generally be at or just under 90 degrees (maximum leverage). The 90* rule isn't set in stone, but if it's more than 10* away from 90 it is going to raise red flags for me.

*If the trailer is full of trash, leave it for next poor schmuck & look for another empty (kidding -- sort-of).

2) Confirm that the registration & DOT inspection paperwork are there & current, then hook up, turn on lights & 4-ways, & with tractor brakes on, supply trailer with air (push in red knob) building up 120+psi pressure as truck is (high) idling.

3) Turn off truck, & walk around trailer checking lights, more closely inspecting tire tread/sidewalls, lugnuts/wheels, and listening for air leaks. Confirm mudflaps are securely attached and extend down to at least the bottom of the trailer's wheel.

4) Duck-walk under trailer near tandems & hit each drum with hammer/crowbar to make sure it rings (a dull thud indicates a crack).

5) Confirm that each brake shoe (2 per drum) has at least 1/4" of remaining lining at the center of the shoe.

6) At this point use crowbar to pry each slack adjuster away from the brake chamber until the brake linings contact the drum, making sure there is less than 3/4" of pushrod travel (2" if you're having someone apply then release brakes from cab).

*If you're going to be lazy and not get under trailer to thwack drums/pry slack adjusters, at least look for the clean portion of the pushrod (where the rubber dust boot swipes away dirt/grime) and make sure it isn't 2" or more...

7) Make sure trailer frame/under structure is in good shape and that the sliding tandems are locked (all 4 pins) in a location legal for your intended route.

8) Wedge crowbar/tire knocker between seat and brake pedal to apply brakes. Walk to back of trailer and confirm all brake lights are functioning.


By about the 100th time you do this, you should be able to finish in 5-7min...

recommended reading: http://www.mpi.mb.ca/PDFs/AirBrakeManual/ABM_Section8.pdf