If you make your living as a long-distance driver, distributing products to remote destinations using your own articulated lorry, then you need to be constantly aware of your truck's condition. You need to be proactive about its maintenance, but you also need to be aware of its normal behaviour "on the road," so that you can immediately consult with your mechanic when something starts to go wrong. Remember, the more information you give to the expert based on your real-world driving experience, the easier it will be for them to fix the issue. Consequently, if you're experiencing some problems with your brakes, how can you narrow this down?
Where to Start
Obviously, your vehicle will not perform correctly unless the complicated brake system found in this type of vehicle is adjusted correctly. Assuming that it is and that it's been working okay up until now, then your current challenge may have something to do with balance or timing.
Braking effort needs to be split equally between each wheel for optimum effect. This means that the effort must be the same on the right and left and through each axle configuration. Any problem with balance in this area will typically manifest as a tendency to pull to one side during heavy deceleration.
It is possible that the drum on one wheel has glazed over, or the lining material may be faulty. It's also possible that the brake actuator could be malfunctioning or that there is a kink in one of the air hoses. These are just a few of the potential culprits, assuming that the balance was okay prior to this point.
To help the mechanic narrow this down, tell them exactly when and where this problem appears. Is it during a high or low-speed manoeuvre, or only when you apply a lot of pressure? If you hook up a different trailer to the vehicle, do you still notice the issue?
As you may know, the brakes on a typically-articulated lorry are timed very precisely and will activate from the rear towards the front, in sequence. If this is not the case, it can cause all manner of instability issues, or apply excess loading to one particular axle. For example, if the brakes on the towing tractor apply before the trailer, then you could lose control as the heavy trailer tries to push the towing vehicle in a different direction. Conversely, if the trailer brakes come on and don't release very quickly, then they could pull everything back and cause the entire rig to slide uncontrollably.
Issues in this area are typically due to valves and pressure differentials. There may also be a kink in a pipe, preventing the chamber from evacuating efficiently and causing the brakes to remain active for a split second too long.
Passing over the Detail
Hopefully, you will be able to explain the situation to your truck mechanic with as much detail as possible. This should help them get you back on the road without too much delay. For more information, contact your local truck servicing repair company.