Runaway Trucks

more often then not, especially on fleet equipment that is “maintained” by bean counters, auto slacks are junk because they never get greased

7/16, 9/16, and a 3/4” wrench and a pair of vise grips should be standard equipment In every truck

 

Not ignoring slack adjuster inspection and maintenance and specifically making sure that the ASA greased regularly and doing good pre/post trips solve that problem.

NTSB as stated for over a decade that manually adjusting automatic slack adjusters is dangerous and unacceptable.

From the above PDF:

Note that less than 1% of CSA violations are due to 'Brake(s) out of adjustment' and yet more than 50% are under 396.3(a)(1).

I get that a lot of mechanics may be too lazy to go grab the grease gun and spend the 60 seconds of time to grease the ASA, but file work orders or do the work as the 4 point violation will get you and as stated above having non-functional, manually adjusted slack adjusters is dangerous and a CSA violation.

IMHO in this poll that would be "driver caused" as it is far easier to find an in-operable automatic slack adjuster than really measure travel. As there are several NTSB cases and they have tried for decades to get people to stop doing this I am betting they would blame the driver too.

 

If you have to put a wrench on an auto slack it is junk, doesn’t mean you can’t nurse it for a week or two until you have the time to replace it by checking the adjustment daily with a wrench

we still have stuff in the yard with manual slacks, perfectly legal on anything made before October of 1996....

 

It says in that PDF that adjusting an automatic slack adjuster can screw up the inside. Is that true, or if you have a screwed up automatic one, you can just treat it like a manual one, and adjust as necessary?

 

it will strip the automatic adjuster by wrenching on them, lack of grease kills them more then anything, that being said, in the real world if I were to notice a slack going bad on the road I would manually adjust them JUST to get me home so I could replace it, not continually run it as a “manual” slack

 

No, if you have a newer truck functioning ASAs are required. 4 point non-OOS if your brakes pass all the other criteria.

In the above crash the ASAs worked when the NTSB adjust them out and applied the brakes several times.

 

You can treat as manual. You have no control when the company will replace.. and it's better then having csa for oos.

I've had all 14 on the current rig replaced 3 times in almost 5 years.

I've had a couple companies that were lazy.

As long as they click when you back em off. They can still be used. When the click is gone. It's time to go as they're no longer locking in.

 

I have no choice but to believe this story. You couldn’t make one up that good. Sure enjoyed reading about the “good ole days.”

 

To add to that the violation code is 393.53B "CMV manufactured after 10/19/94 has an automatic airbrake adjustment system that fails to compensate for wear"

It appears to be the 11th most common violation but will probably lead the DOT officer to look for 393.47E "Clamp or Roto type brake out-of-adjustment" which may result in them measuring the actual braking force and result in a 396.3A1BOS "Brakes Out Of Service: The Number Of Defective Brakes Is Equal To Or Greater Than 20 Percent Of The Service Brakes On The Vehicle Or Combination"

The 396.3A1BOS is the one that is the OOS

I am betting that the technicians at your company are just putting in a few pumps if they live it at all.

You need to keep adding grease until the grease coming out is clean. I am betting that they are just shoving dirt and road grime into the cavity and stopping when they see any new grease coming out.

I would be tempted to carry a grease gun and doing it myself....but I don't really have a way to manually adjust at DOT specs reliability while staying in the limits.

Hopefully disc brakes take over quickly and these problems go away over the next few years.

 

My dad had that happen in reverse with a 238 up against a dock LOL. Slam slam slam and it finally coughed to a stop