Part of the routine checks an operator must do before putting a used dump truck on the road is to check the brakes. Although this is mandatory for just about any other vehicle, let me reiterate its importance on big rigs. The sheer size, weight and power of a used dump truck are the biggest reasons to regularly check the truck’s brake system before operating it on roads. Any failure resulting from the truck’s brake system could make it a rolling disaster.
Brake Basics 101
First, let’s learn some of the basic things about truck brakes and how it generates power to stop several tons of moving vehicle from 60 mph to 0 mph in no time. The brake system used in any used dump truck is pretty unique. Unlike conventional cars that use brake fluid, trucks use compressed air brake systems. This means that instead of the typical brake fluid, it uses the power of compressed air to transfer the force from the brake pedal to the truck’s brake drums. The system is very similar to the powerful brake system used by trains.
The reason why a used dump truck uses compressed air instead of conventional brake fluid is because of the unlimited supply of air vs. an inherently limited on-board supply of oil. Hydraulic brake systems have a tendency to leak and can potentially run dry. Although brake system designs that use brake fluid have improved over the years, it’s still incomparable to the reliability and stopping power of the compressed air brake system.
On an air brake system, a compressor powered by the truck’s engine continuously fills a storage tank with air as long as the engine is running. The truck will never run out of air supply even when the brake line leaks air. This feature makes it a safer and far more reliable brake system application for a used dump truck.
Brake System Flaws
Although reliable, it is also important to know that the air brake system has its own flaws. For one, air brake systems suffer from air brake lag. After pressing the brake pedal, the truck driver has to wait for a fraction of a second for the brake to set in. The momentary brake lag occurs due to the amount of time it takes for air pressure to build up along the brake lines and put pressure onto the brake pads. This problem is common on any used dump truck that utilizes air brake systems; but it isn’t a serious issue since this flaw is less than a second long. A good commercial vehicle driver should know the brakes’ limitations as well as how to negotiate with it.
Brake System Routine Inspections
To ensure safety, it is always important to perform a routine inspection on the truck’s major components, especially the brake system. Refer to the used dump truck manual that hopefully came with it on how to check the truck’s acceptable leakage rate. If the air pressure drops faster than it normally should, have your brake system checked for air leakage. Constant pressure and heat from heavy braking will eventually wear out the brake pads. Always replace your brake pads at regular intervals as specified by the truck’s manufacturer.
Brake System Test – Before Regular Driving
Before driving a used dump truck, it is important to do a quick brake test to check the reliability of the brakes. Start with the truck’s parking brake. Engage the parking brake and try moving the vehicle. The parking brake should not allow any movement. Next, test the truck’s service brake. Move the truck slowly, and apply the brakes. Observe for any abnormalities such as pulling to one side or delayed braking. If any of these occur, have your braking system checked.
Brake System Test – Before Steep Grade Driving
Lastly, before tackling any steep grade roads, take time to stop by in the available brake check areas to verify the truck’s brakes are capable of providing the stopping power the road conditions demand. You don’t want to find out driving on a steep grade that the braking system is not able to handle this particular driving situation!
New brake technology is continually being developed and presented to the used dump truck industry. Until you can afford the higher price tag for the latest technology, the safe maintenance of the braking system on a used dump truck is imperative. You do need to stop, look and read all of the available literature and be as current as you can be on your vehicle’s braking system. Safety is always first!
Central Truck Sales is the industry leader in providing quality Used Dump Truck.