Wabco brake unloader valve

Types of Wabco brake unloader valves

A Wabco brake unloader valve performs the critical function of reducing the air pressure within the brake chamber following the unloading or expansion of refrigerant gas from the air suspension system. Two prevalent types of the Wabco brake unloader valve are commonly used in the heavy-duty industry.

• Wabco Straight Unloader Valve

  The Wabco straight brake unloader valve features a straight body and is primarily used in Wabco 20k, 24k, 26k, 30k, and 33k axles. Although it is widely utilized in the heavy-duty industry, it is not manufactured anymore. Because of its simple design, it effectively unload the air from the brake chamber.

• Wabco Slide Unloader Valve

  The Wabco slide brake unload valve has a slide mechanism and is used in various applications. Some have a yellow knob, while others have a blue one. The yellow one is commonly used in Wabco 20k and 24k slide valves, whereas the blue one is present in Wabco 30k and 33k slide valves.

  The Wabco slide unloader valve performs the same function as unloading air from the brake chamber. However, it is manufactured with a more robust and advanced design. As a result, it is more durable and long-lasting. The mechanism of the brake unloader slide valve is smoother than the straight one. Moreover, it can handle more weight and air pressure.

The Wabco unloader slide valve is further categorized into two different types based on the bracket.

• Wabco Short Bracket Slide Unloader Valve

  The Wabco short bracket slide unloader valve has a short bracket which makes it suitable in certain applications. This unloader valve links the slide to the valve by using two bolts.

• Wabco Long Bracket Slide Unloader Valve

  The Wabco long bracket slide unloader has a long bracket which makes it a more versatile option. It can be used in different applications by changing the bolts and spacing.

Specification and maintenance of Wabco brake unloader valve

Specifications

Key specifications related to Wabco brake unloaders are as follows.

• Functionality

  The main function of Wabco brake unloaders is to reduce the pressure of the brake outside the trailer or truck, which in turn helps to improve suspension travel and comfortably seat the cargo goods inside the trailer.

• Design and Structure

  The unloader valve essentially has a main body, an inlet port, an outlet port, a control collar, and a piston. The unloader valve is usually connected with the help of a bolt to the air suspension and the air compressor of the truck or trailer. The inlet and outlet ports are usually connected via air hoses to the air compressor and air suspension of the truck or trailer. The position of the collar usually varies according to the configuration of the vehicle. In most instances, it is near the piston. The collar position determines the amount of air that is let out of the suspension system.

• Operating Pressure Range

  The operating pressure range of Wabco brake unloaders is between 3 to 12 bars. However, it can be as high as 15 bars in some cases.

• Response Time

  The response time of the unloader valve refers to the time taken by the valve to react after a change in air pressure inside the suspension system. The response time is usually between 0.5 seconds to 2 seconds, but it may vary depending on the model of the valve.

Maintenance

Maintaining a Wabco brake unloader valve is crucial to its proper functioning. Regular inspection can quickly determine whether or not the valve requires repair or replacement.

• Visual Inspection: Users can begin by inspecting the valve and looking for any signs of damage, such as cracks or air leaks, which may appear to be hissing sounds or whooshing sounds. In case of air leaks, the valve may end up being less efficient, which may lead to increased suspension pressure and decreased comfort for the passengers inside the vehicle.
• Function Test: The user should perform a function test on the unloader valve periodically. In this test, the vehicle is driven, and the suspension pressure is checked to see if the valve is functioning as it should. The user manual should be checked for the recommended frequency of this test.
• Air Hose: Users should inspect the air hose and ensure that there are no cracks or leaks. If the air hose is damaged, it should be replaced immediately, as damaged air hoses can cause air leakage and reduced efficiency of the unloader valve.
• Cleaning: If the Wabco unloader valve is exposed to dirt and debris over time, its performance may be affected. Therefore, it is necessary to clean the valve periodically to avoid this situation. It is important to note that the valve should only be cleaned with mild soap and water and cleaned using compressed air.

Scenarios of Wabco Brake Unloader Valves

• Long-Distance Transportation

  For goods transportation companies that usually drive for over a thousand kilometers, the brake must be manageable. Hence, they need the unloader valve to reduce the trailer's weight.

• Heavy-Duty Haulage

  Heavy-duty, or rather, off-road vehicles have to climb steep roads in mountainous areas. Such vehicles demand heavy braking. Therefore, they need a unloader to effortlessly control the brake pressure.

• High-Maintenance

  Frequent unloading of the brake liner is quite unnecessary. Hence, it leads to lower liner wear and reduced brake quality.

• Faulty From the Start

  A faulty unloader valve will keep the brakes from unloading. This will make the vehicle harder to move, as if the brakes were still on.

• Tramcars and Buses

  In large public transport such as buses and the tram, the unloader valve is in charge of breaking. Tram and bus vehicles are usually heavy and require more modulation of the brakes.

How to choose WABCO brake unloader valves

When selecting the WABCO brake unloader valve for the vehicle, it is vital to consider the vehicle's make and model to ensure the unloader valve fits correctly and functions as intended. In addition, the check for any signs of wear or damage to the valve, such as cracks or breaks, should also be made. A thorough inspection of the valve helps to determine if it needs to be replaced. Testing the valve's performance is also important. It should unload the air from the brake chamber efficiently and effectively. If the valve is slow or does not unload air, it may need to be replaced.

Always use the proper tools and equipment when handling the brake unloader valve to avoid any damage or injury. It is essential to remember that the brake unloader valve is a crucial component of the vehicle's braking system and should be given the utmost care and attention. If unsure about anything regarding the brake unloader valve, it is always best to seek professional advice and assistance.

When selecting the WABCO unloader valve for bulk purchase, it is advisable to choose different models to fit various truck types. Look for suppliers who offer custom packaging options and branded packaging for resale purposes. It is advisable to buy in bulk to get better rates for resale. Select suppliers with proper quality assurance and certification so that customers will be satisfied with the product's quality. Ensure the suppliers have fast, reliable shipping options so that stock will arrive on time. If using a specific WABCO product code for ordering, ensure to request a sample first before placing a large order. A sample request will ensure that the exact product is required.

Wabco brake unloader valve FAQ

Q1: What does the Wabco brake unloader valve do?

A1: In a driver-controlled unloading system, the brake unloader valve permits the passage of air from the cab into the trailer. When this occurs, the brakes of the trailer will become unlatched.

Q2: Where is the brake unloader valve located?

A2: The brake unloader valve is commonly found in the tractor's brake system. It is usually located close to the air brake chamber.

Q3: How do you identify a brake unloader valve?

A3: Brake unloader valves can be identified easily because they have a small hose that connects to a chamber or port in the valve.

Q4: Are brake unloader valves universal?

A4: No, brake unloader valves are not universal. Different vehicles may use different unloader valves that have distinct sizes and fittings. It's important to find a unloader valve that fits the vehicle accurately.