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Brake adjustment
How often or miles do we adjust brakes? Do most turn slack adjuster tight then back off 1/2 turn or use yellow gauge for stroke and adjust that way? Using gauge it ends up 1/2 back off?
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4 Replies
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I suspect your coach has automatic slack adjusters.
But……and this is a big but, they are mechanical and you need to verify the adjustment periodically. I think on the Bendix site they describe brake chamber pushrod travel. I cannot remember the distances, but they vary based on brake chamber size. To measure, every time the coach is in the air or over a pit verify the service brakes are correctly adjusted by measuring the push rod travel from the brake off position to brake applied position. It is a two man operation because someone needs to be under the bus doing the measuring at six places, and someone needs to be applying the service brake as each position is measured.
There is a lazy man’s way to know if you are close with the adjustments, and that is to apply the service brakes and where the pushrod comes out of the brake chamber can, if you see a red ring the adjustment is wrong because the push rod is at the very end of its travel.
To do this test (either way) the parking brake needs to be released.
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Yes Jon it does have automatic slack adjusters, so I guess if you wanted to check you can tighten down and see how far they go? Then back off to where it was
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When working on brake chambers on a coach with automatic adjusters there is no alternative to backing off the adjuster and when appropriate tightening it back up to get the correct push rod travel.
But if you read about slack adjusters there is usually a dire warning not to touch them or adjust them.
Having said that, if you feel compelled to adjust them at least understand the process for backing them off, and then to adjust them there are two options that I can see. First, adjust them yourself. Use the tightening procedure you are comfortable with and just be sure you aren’t screwing it up. The second option is not as elegant but it works. Disconnect the service brake hose. Using shop air and a rubber tipped blow gun, alternately give a shot of air to the service brake inlet to the brake chamber and then release. If the adjusters are working you will see the brake adjustment being made with each shot of air until the correct adjustment is made (assuming the adjusters are working).
I admit I threw caution to the wind when doing brake chamber work and made the final adjustment manually. But I never screwed with them after that because after my repair work was done I verified everything was adjusted correctly and working by measuring push rod travel at various service intervals. There is always a lot of comments and complaints about automatic slack adjusters but on my 97, for my 8 years and over 100,000 miles I put on it they were flawless.
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