Much like passenger cars and trucks, large truck brake repairs are a frequent maintenance issue. The braking system is the most important of any car, truck or big rig. Slowing down and stopping a several ton vehicle is of paramount importance, especially when it is cruising at 60+ miles per hour. Large commercial vehicles have a truck brake manual that details the use of the air brakes, the specialized braking method that brings big rigs safely to a stop. The same problems that affect passenger vehicles such as worn pads, leaking cylinders, etc, affect large trucks, but air brake problems are an added concern.
Common Problems
Wheel cylinders, master cylinders, brake pads and other brake system components go out and need to be replaced on large trucks just the same as passenger vehicles. Because large trucks are accustomed to driving such long distances constantly, it requires more frequent maintenance. If you drive a long haul truck for a living, you are undoubtedly familiar with the regular routine maintenance required to keep them on the road. Brake systems are the most important. Also of concern are the air brakes on a large truck. There are several things that can happen to air brakes. There are things to watch out for and preventative maintenance that can help you avoid big problems down the road.
Air Brakes
Truck air brake parts are commonly replaced because of all the work the air brakes are put through on a daily basis. Imagine coming down a mountainside hauling 25 tons and having to stop--day in, day out. Air brakes work by using pressurized air to stop a vehicle. Basically, there are few basic rules with air brakes. The minimum operating pressure for a large truck is 100 psi. It should take no longer than 2 minutes to go from 85 psi to 100 psi. This is called the air pressure buildup rate. Lastly, the cut-out pressure should be between 120 and 135 psi.
Common Problems with Air Brakes
Water should never build up in the air lines. This could cause problems, especially when you are trying to stop a truck in colder weather. Many modern truck systems have automatic drain valves in each air tank to protect against this.
Worn rubber seals will cause air to leak from the line. If too much leaks out, the truck will have to sit, so the air couplers should be checked frequently. Too much braking can lead to problems as well. When brakes lock up, skid marks are left on the road. This is a common problem among inexperienced drivers and is something that should be avoided. In order for trucks not to lose their braking power, many modern systems have dual brakes, one being an anti-lock braking system.
Air brakes are a great way to stop large trucks, but there are many components that have to be checked frequently in order to avoid an accident. If you drive a big truck, familiarize yourself with the possible problems in order to avoid them if at all possible.