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Brake Tips to Avoid Downtime

Andy Finn is the parts manager at Tom Nehl’s Waycross location. Before this location was part of the Tom Nehl Team, Andy and his father owned it as Finn Brothers Brake Service (his father and uncle started that business in 1947). So, you could say that Andy knows brakes. We sat down with him to get his best practical tips to avoid being out of service from a brake inspection.

When you get stopped with an air brake inspection, or any inspection, down on the side of the road is not an option. It's a waste of your time, and waste of your money. So, let's go over few tips that you can use to help from being on the side of the road, or sidelined by a brake inspection.

Automatic Slack Adjusters

Automatic slack adjusters have been required on all trucks since 1993, so do not take your automatics off over a few dollars!  Automatic slack adjusters come in many designs, but the levered kind is very common. All slack adjusters also have a grease fitting. A small amount of grease when you do that PM is all you need. Do not pump it full of grease, just apply a small amount. If your slack is a type with a rubber boot, keep an eye on it. When the boot is torn, it’s time to replace. Some slacks also come with a release pawl.  If you're going to adjust to let the brakes out on this one, you have to pull that pawl out. Tom Nehl has those tools that you can buy to pull those out and use the wrench to back it off.  It’s very important that you never mix and match one wheel with another, and always use the template that comes with that slack adjuster to set it up. Those angles are crucial. You need to set it up properly every time. Don't guess.

Brake Shoes

Whenever you look at your brakes, you say “I've got plenty of lining left.” Take a closer look for the go/no-go area. All brake shoes are now required to have this. There's a line, a V cut, or a notch, depending on the type of shoe to indicate the no-go area. When you get to that point, DOT considers that shoe worn out. So, you want to look for that and see how close you are.

Brake Drums

99% of drums on trucks today are 16 and a half inch drums. When they wear down to 16 and five eighths, DOT considers them to be worn out. That is only a sixteenth of an inch per side. It’s tempting to look at that drum and think, oh it's not bad, but a sixteenth of an inch is worn out, so keep a close eye on those drums!

Air Leaks

Air leaks can sometimes be audible, but sometimes you can't hear them at all due to engine noise or other factors. When that happens, a good way to test for that is with soapy water. For instance, if you think you might have a leak in a compressor braided line, where air can seep out and it’s hard to detect, get a soapy solution in a spray bottle and spray down the line. If you have an air leak, it will form air bubbles so you can see where your leak is. You can also do this anywhere on your truck.

Mystery Air Leaks

Air leaks on a truck sometimes only happen during certain situations.  For instance, when you push your yellow button in to release the brakes on the truck, and then you start having a leak. That does not mean that button is bad or the valve that that air is coming out of is bad. That means that you have a bad parking brake chamber. You should check your parking brake chambers one by one. Then you can narrow down which one is faulty and replace that chamber.

Also, on an air compressor I get calls that say, “Hey my truck only builds up 30 pounds of air, what's wrong? Have I got a bad compressor?” No. nine times out of ten it is not a bad compressor, it is a non-audible air leak. If your air compressor will build to 30 pounds, it will build to 150 pounds, so hunt for that leak!

Andy and the entire Tom Nehl parts team are always happy to help you with your trickiest brake questions, or to advise on any type of truck part. To reach our Waycross location, call 912-283-7473. To reach the parts department at our flagship Jacksonville location, call 904-388-5443.