12
2026
-
10
If your brakes show these issues in winter, it's probably time for maintenance
As winter approaches, truck drivers must ensure their brake systems are protected against water and freezing. Excess moisture in the brake system can be very dangerous. At best, it can cause the brakes to lock, preventing the vehicle from moving or even igniting the tyres, damaging the vehicle. At worst, freezing in the brake lines can cause brake failure, increasing safety risks. Here’s some information to raise awareness and help avoid these situations.
▎How to prevent brake line freezing causing brake failure and increasing safety risks
First, let’s look at the problems caused by excess moisture in the brake lines. The four-circuit system, brake master cylinder, trailer throttle valve, relay valve, and the three-axle trailer valve, or ABS control valves – everyone knows the entire brake system depends on these components working together. If any one fails, it can lead to system faults.
For example, if the brake valve does not return smoothly after releasing the brakes, it can cause dragging brakes, ranging from mild to severe, with some wheels locking and others not locking, particularly when the brake is dragging but not fully locking.
Due to the heavy momentum of loaded trucks, drivers might not notice this. This is when the temperature of the brake drum can rise sharply, possibly igniting the tyres and causing property damage. The reason is water inside the brake valve or the use of antifreeze in the air line, which causes multiple hazards.
A few key points: water can damage the grease inside the brake valve, causing the control piston’s seal to dry out. During braking, this causes friction between the piston and the valve body, preventing smooth movement and affecting the piston return after braking. In an emergency, the piston might get stuck, preventing the valve from opening and causing brake failure with potentially serious consequences.
If excess water accumulates above the piston, the piston can’t return to its original position due to water pressure. This prevents complete separation from the underlying valve, and a small amount of air may continue to reach the wheel cylinder, causing braking. Figure 1
Figure 1
The reason for the brakes is as mentioned above. Some vehicles suffer damage due to the above issues, and individual truck drivers may blame the maintenance staff or a certain pump valve. In reality, the real culprit is the moisture in the braking system and the drivers not checking and maintaining the braking system themselves. What caused the brake valve to be in its current state as shown below?
▎What caused the brake valve to be damaged?
Figure 2
Figure 3
As car owners probably know, moisture in the brake lines or antifreeze in the air circuit not only damages the brake valve piston chamber but also damages the return springs in the brake valve air source chamber, causing them to rust and seize or break, which leads to the brake valve leaking air. It can also damage the brake actuators (brake chambers); let's start with the main vehicle's actuators in Figure 4.
Figure 4
Damaging the middle partition O-ring and a decayed push rod can cause air leakage; after releasing the handbrake, air pressure can pass from the broken brake chamber to the foot brake chamber. Rust on the broken brake piston and the inside of the brake cylinder can create dry friction, causing sticking and reducing or even losing the broken brake function. Also, the same situation applies to the trailer air chamber as shown in Figure 5.
Figure 5
The push rod between the corroded brake chamber and the foot brake chamber can wear out the O-ring, causing air leakage in the same way. Truck friends can summarise that with the above issues, not only do brake system repairs become much more expensive, but the key point is that safety is compromised, as the hazards caused by moisture in the brake system are numerous. Imagine what would happen if the brake pipeline is filled with water and freezes in winter. Some truck friends might initially think the handbrake won't release, and the vehicle cannot move. Congratulations, you've got half of it right; the handbrake won't release and the vehicle cannot move, but that's not the scariest part. The vehicle might not move but still can't stop. If the air source or control line of the foot brake valve freezes, you won't be able to stop even if you want to, and that's the most frightening. In other words, when the brake pipe has no air while driving, everyone understands the consequences without me having to explain. I have been working with brake systems for over 20 years and have seen too many similar cases. Truck friends must take preventive measures and control moisture at the source. Many think that just replacing a dryer will do, but not all dryers are effective; the quality of the internal molecular sieve particles varies. Many poor-quality ones have no drying capability and are merely decorative. Some truck friends find that after replacing the original dryer's gas cylinder, which had no water, the new dryer releases a lot of water, and the reason is clear. Speaking of which, the dryer’s quality alone does not determine moisture control; the air pump, condenser control form, pipeline setup, temperature, and back-blow cylinder all affect the result. Through technical installation upgrades, moisture can be effectively controlled. If truck friends have the above issues or brake problems, I am here to answer for free. ▎Editorial Note That's it for now. I hope this article helps truck friends understand the importance of safety awareness and taking measures seriously. Remember, safety cannot be compromised. In the next article, we will talk about winter vehicle brake system anti-freeze measures and steps. Finally, Wang from Anshun Brakes wishes all truck friends: may your vehicles travel thousands of miles safely with Anshun by your side.
Previous Page
Previous Page
Focus on the research and development of automotive brake systems and pneumatic brake valves to promote the development of the auto parts industry!
Contact Information
Telephone:86-575-87438928
Mobile:8613252110178
QQ：1185450863@qq.com
Address: No. 461, Advanced Village, Fengqiao Town, Zhuji, Zhejiang Province
Online message
Submit your information and we will contact you as soon as possible.