Troubleshooting Brake Problems for Truckers

edralyn
August 8, 2013

If you operate a large truck, keeping the brakes in good working order is of the utmost importance. The National Highway Traffic Safety Administration says one out of every eight accidents involves a large truck, which adds up to 500,000 accidents every year. If your brakes won’t depress or they sink all the way to the floor, you might have serious issues with your system that can put you and other vehicles on the highway in danger. If you want to get a good idea of what exactly is going wrong with your brakes before you pay a mechanic to inspect them, there are some clear ways to narrow down the problem. Some parts can be relatively expensive and simple to replace, but if you let it go on too long without repair, you can cause more serious and more expensive damage.

1. Problems with Brake Lines

Some trucks operate a hydraulic brake system, where the brake lines use fluid to apply pressure to the wheel cylinders to create the tension needed for good working brakes. But many trucks, especially larger and more recently manufactured vehicles, have air brakes which use air from a compressor instead of fluid. Either way, it’s relatively easy to tell if the lines are leaking. If your brakes go all the way to the ground but you don’t notice a screeching sound, you should check to see if you’re leaking fluid. If you have air brakes, a hissing sound will indicate a problem with the lines. Hydraulic brake lines can sometimes be repaired by adding fluid or purging air bubbles. But when the issue won’t go away, it’s more likely that there is a puncture in the lines and they need to be replaced.

2. Problems with Brake Calipers

The brake caliper houses the brake pads and pistons, and they’re usually the culprit if you find your brakes are sticking and either won’t depress or remain slightly depressed all the time. The sticking sometimes happens if you haven’t driven your vehicle in a while, because corrosion on the caliper stops it from functioning normally. Sticking brakes are a big problem. They lead to dangerous driving conditions and can wear down your brake pads in record time. If you’re not sure whether your calipers have corrosion, it’s easy to remove your tires and inspect the guide pins. Normally, you can tell just by looking at them whether they are old and dirty, lacking lubrication, or stuck in the rotor. If you recently replaced your brake pads, sometimes caliper guide pins aren’t put back in all the way and can end up causing damage.

3. Considerations for Air Brakes

If you have an air brake system, like many trucks do, there may be more indicators of what’s wrong and more areas to troubleshoot. Heavy trucks can have problems with their slack adjusters, especially if they’re used to tow large items. If it’s an auto slack adjuster and you find yourself needing to constantly check and adjust it, it may be wearing down and need to be replaced. There can also be a problem with the pressure gauge, which should operate between 100 and 125 psi. The easiest way to diagnose air breaks is to check the braking time and smoothness. If your vehicle is taking much longer to slow down than it has in the past, there could be a problem with adjustment, low pressure, or a faulty hose or valve. Manufacturers are required to equip modern vehicles with warning signals whenever the pressure goes too low.

It’s always safest to check with a trusted mechanic when your brakes start to behave strangely. Operating a large vehicle can be dangerous for you and others on the road, so you never want to take chances. Don’t repair your brakes yourself if you don’t have adequate experience. Brake systems can be complicated, but if you responsibly investigate all signs of damage, you’ll be safe on the highway for a long time to come.

Dan Nielson blogs about highway safety and accident prevention and knows when towing more than one vehicle it is important to maintain the slack adjusters.