Brakes are essential to any vehicle and on heavy trucks that haul big loads, maintaining the system is the best way to keep them operating correctly. The systems in heavy trucks have some differences than brakes on light duty cars and trucks. While the systems may function somewhat differently, they both need regular maintenance to perform at their best.
Visual Inspection of the Brakes
One of the most important parts of maintaining the brake system on any truck is a regular visual inspection of the pads and shoes. You can see the brake pads on the front of the truck from behind the tires if you are under the truck.
The rear pads of the truck most likely have shoes on them, and they are harder to see, but there is often an inspection hole that will allow you to see the amount of friction material on the shoes.
If the shoes or pads look thin, you need to have them inspected further by removing the wheels and removing the brake drums from the axles. A weekly visual inspection is a good idea for a truck that sees a lot of over the road miles and can save you from dealing with an expensive breakdown.
Service the Brakes Completely
While some people feel that changing the brake pads and shoes is servicing the brakes on the truck, that is not the case. Disassembly of the brake system is essential and allows the technician to check the pads, shoes, drums, rotors, and all the small parts in the system.
The system generates a lot of brake dust, and when it mixes with the dirt, grease, and water in the brakes, it can get into everything. Cleaning all of that out and regreasing the brakes should be a priority everytime you disassemble the brake on your truck.
Along with cleaning, be sure to check the thickness and condition of the brake rotors and drums whenever they are off the truck. Each part has a minimal thickness, so check with the dealer or manufacturer to get the measurements for your truck.
Drums and rotors with ridges in them will cause the pads to wear faster and can cause the brakes to pulse or vibrate when you use them. Heavily worn drums and rotors require replacing as soon as possible.
Check the Slack Adjusters
The slack adjusters do just what they sound like they do - they remove the slack in the brake systems as the shoes wear down. The slack adjuster is a shaft with an s cam on it, and as the shoes were, it turns and pushes the shoes in further so that the brakes do not begin to feel soft or mushy to the driver.
Slack adjusters are on the pre-trip inspection in the US so there is little reason that they should even not work, but they need cleaning and lubricating from time to time.
When the brakes are off the truck, lubricate the slack adjusters with heavy grease to keep them working properly. If they bind or freeze, a worn brake shoe could jam inside the drum, causing a brake failure that could be very dangerous.
Check the Air Lines
Finally, check the airlines on the brake system regularly. If you have a leaking airline, the pressure in the system can drop. The air system needs at least sixty pounds per square inch of air to function but should be near one-hundred and twenty pounds to work optimally.
If the air in the system drops below sixty PSI, park the truck until a mechanic can find the problem as it is not safe to drive with air pressure that low.
At Clutch & Brake Xchange Inc., we help you keep your brakes working with the right parts to fit your rig. Come by or call today so we can help you find what you need.