What malfunction of the brake system prohibits the operation of a truck or bus: complete guide

• 🚚 Air leak from the system. Standard indicator: pressure drop of more than 0.5 bar in 30 minutes with the engine off. Checked with a pressure gauge.
• 🔧 Four-circuit safety valve malfunction. If it is stuck, if one circuit breaks, all the brakes will fail.
• ❄️ Freezing of condensate in winter. At sub-zero temperatures, water in the pneumatic system blocks the valves.
• 🔥 Overheating of brake drums. Leads to “boiling” of the pads and loss of braking efficiency.

A particularly dangerous malfunction brake force regulator (aka “sorcerer”). In pneumatic systems, it distributes pressure between the axles. If the adjuster is broken, the rear axle may not brake at all, resulting in vehicle rollover during sudden braking.

How to check air brakes without a stand?

1. Start the engine and wait until the system pressure reaches 6.5–7.5 bar (the norm for most trucks).
2. Turn off the engine and watch the pressure gauge. Pressure drop by more than 0.5 bar in 30 minutes - a sign of a leak.
3. Press the brake pedal with the engine off. The pressure should drop smoothly, without jerking.

5. Fines and liability: what you face for driving with faulty brakes

Operation of a cargo vehicle or bus with defects in the braking system is punishable by Article 12.5 of the Code of Administrative Offenses of the Russian Federation. The amount of the fine depends on the severity of the fault:

• 💰 500 rubles - for minor faults (for example, an unadjusted parking brake).
• 💰 2,000 rubles - for critical defects (liquid leakage, inoperative circuit).
• 🚔 Traffic ban - if the inspector considers that the vehicle poses a danger. In this case, you will have to fix the problem on site or evacuate the car.
• 📜 Deprivation of rights for 2–6 months - if faulty brakes cause an accident (according to Article 12.37 of the Code of Administrative Offenses).

In addition to fines, the driver bears administrative and criminal liabilityif an accident with serious consequences occurs due to faulty brakes. For example, according to Article 264 of the Criminal Code of the Russian Federation (“Violation of traffic rules resulting in the death of a person”) is punishable by imprisonment for up to 7 years.

What to do if an inspector stops your vehicle because of the brakes?

1. Ask to see inspection report indicating the specific malfunction.
2. If you don't agree, demand it bench check (the inspector is obliged to provide this opportunity).
3. If the defect is confirmed - don't driveuntil you fix the problem. Calling a tow truck will cost less than a fine + evacuation initiated by the traffic police.

⚠️ Attention! If your truck or bus was involved in an accident, and the expert’s conclusion indicated that the reason was braking distance does not comply with standards, the insurance company has the right refuse payment under compulsory motor liability insurance. Moreover, the blame automatically falls on the driver of a vehicle with defects.

6. How to avoid problems: prevention and regular inspection

To avoid getting into a situation where an inspector prohibits the operation of a vehicle due to brakes, follow these recommendations:

• 📅 Check your brake system before every long flight. Especially if the truck or bus has been idle for more than a week.
• 🔧 Change brake fluid every 2 years (or every 40,000 km for hydraulic systems). In pneumatic systems, drain the condensate from the receivers once a month.
• 🛠️ Adjust the gaps between the pads and drums every 10,000 km (for air brakes, check the automatic adjusters).
• 🚘 Get diagnostics at the stand at least once every 6 months (even if the inspection is once a year).

For buses and trucks with air brakes required:

• Check system pressure before departure (must be at least 6.5 bar).
• Lubricate brake chamber rods every 3 months (use special lubricant, e.g. LIQUI MOLY Bremsen-Anti-Quietsch-Paste).
• Check hose tightness soap solution (especially in cold weather).

If you are in control by bus, pay attention to anti-lock braking system (ABS). According to TR TS 018/2011, its malfunction is not a reason for prohibiting operation, but significantly increases braking distance on a slippery road. In some models (for example, MAN Lion's City) ABS is integrated with the exchange rate stability system (ESP), and its failure can lead to skidding.

7. Frequently asked questions and misconceptions about the braking system

Truck and bus drivers often encounter myths about braking systems. Let's look at the most common ones:

Misconception 1: “If the brakes work at least somehow, you can get to the service station.”

❌ Dangerous judgment! According to traffic rules, any malfunction affecting braking performance, is the reason for the prohibition of operation. Even if the pedal “catches”, but the braking distance is increased, the inspector has the right to stop your vehicle.

Misconception 2: “It is normal for a pneumatic system to leak air.”

❌ No! Allowable pressure drop - no more 0.5 bar in 30 minutes. If the air leaves faster, this is a sign depressurization, and operation is prohibited.

Misconception 3: “ABS does not affect safety, it can be turned off.”

❌ ABS in trucks and buses required (according to TR TS 018/2011). Its failure increases the braking distance on a wet or icy road by 1.5–2 times.