Wabco 4757130020 Automatic Load Sensing Valve

Description

The Wabco 4757130020 is an Automatic Load Sensing Valve crucial for maintaining optimal braking performance in air brake systems. This valve is typically used in heavy-duty trucks, trailers, and buses to automatically adjust the braking force based on the vehicle's load. It ensures consistent and safe stopping power regardless of whether the vehicle is fully loaded, partially loaded, or empty. The valve features a mechanical, dynamic type of operation with an actuation angle of -50° to 20°. Its dimensions are 129 x 131 x 322 mm and features mounting points for 4x M8 bolts, and port threads of M22 x 1.5, 2x M16 x 1.5, and M22 x 1.5. With OE specification, this valve enhances safety and extends the life of the braking system through consistent and reliable operation.

Key Features & Benefits

This valve basically monitors how much weight your vehicle is carrying and adjusts the air pressure to the rear brakes accordingly. It’s constantly measuring the chassis deflection – how much your suspension is compressing from the weight. It then proportionally increases or decreases air pressure to the rear brake chambers. Think of it like a smart regulator; it doesn’t just send a fixed amount of air, it adjusts how much air goes to the rear brakes based on the load. It’s a crucial part of your air brake system, specifically designed to prevent wheel lockup, especially when you’re lightly loaded. Older systems, or ones without this valve, apply the same braking force to the rear wheels regardless of weight. That’s a problem because if you’re not carrying much, those rear wheels can easily lock up during braking, leading to skids. This valve makes sure the rear brakes don't overpower the front brakes, maintaining stability.

Symptoms, Risks & Replacements

It's a really big safety item. If this valve fails, you’ll notice if you’re lightly loaded that your rear brakes might lock up before the fronts, and that’s obviously dangerous. Conversely, if it gets stuck in a certain position, you might not get enough braking force to the rear when you are loaded. Proper braking balance is essential for control, and this valve helps achieve that automatically. You can find these relatively easily – Fixparts Online has a good selection, and getting the right one ensures your air brakes work as designed. It's something you definitely don't want to ignore if you suspect it's failing.

Warranty Information

Wabco Automatic Load Sensing Valve (MPN 4757130020) comes with a 1-year warranty.