Wabco 4757200040 Automatic Load Sensing Valve

Description

The Wabco 4757200040 is an Automatic Load Sensing Valve critical for maintaining stable and efficient air brake system performance in commercial vehicles. This valve is typically used in heavy-duty trucks, buses, and trailers to automatically adjust braking force based on vehicle load. It ensures optimal braking performance whether the vehicle is fully loaded or running empty. The valve features a mechanical, dynamic type of operation with a regulating ratio of 1:5.3 and a break point of 0.6 bar, operating within a temperature range of -40°C to +80°C. Its dimensions are 152 x 179 x 225 mm. The design includes features like an integrated silencer for reduced noise, and utilizes M22 x 1.5 JED-388, M22 x 1.5 JED-152, and M16 x 1.5 JED-388 port threads. This valve is an OE specification part, providing reliable and consistent performance for demanding applications.

Key Features & Benefits

This valve basically balances the air brake force between the tractor and trailer. It measures how much weight is being carried – how loaded up the trailer is – and adjusts the air pressure sent to the trailer brakes accordingly. It’s got an arm that moves with the suspension, sensing the change in load. It then proportionally increases or decreases the air signal. Think of it like a smart regulator, constantly adjusting to make sure you’ve got the right braking power for what you’re hauling. It’s a mechanical – pneumatic device, so it uses both physical movement and air pressure to do its job. It’s a key component in the air brake system, specifically designed for tractor – trailers. It connects to the trailer’s suspension and sends a signal back to the tractor’s brake system. This tells the tractor how much air pressure to apply to the trailer brakes. Without it, you’d either be under – braking a heavy load—dangerous—or over – braking an empty or lightly loaded trailer, which causes excessive wear and tear, and can even lock up the trailer wheels. It works with the spring brakes, too, making sure everything’s cooperating.

Symptoms, Risks & Replacements

It’s really important for safety and preventing damage. If it fails, you'll notice if the trailer brakes aren't applying evenly or are weak, or if they're locking up too easily. That can cause a pull to one side during braking, making it very difficult to control the vehicle. It protects your brakes, tires, and suspension from premature wear, too. It's a pretty crucial safety item. You can find these at places like Fixparts Online, and I’d recommend getting a quality one; it's not a place to cut corners. A failing valve can lead to some serious issues down the road.

Warranty Information

Wabco Automatic Load Sensing Valve (MPN 4757200040) comes with a 1-year warranty.