31-SA3520496-UD | Genuine International® ABS Hydraulic Brake Control Valve

An ABS Hydraulic Brake Control Valve 31-SA3520496-UD is a key part of a vehicle’s anti-lock braking system (ABS). It controls how brake fluid pressure is applied to each wheel during braking so the wheels don’t lock up.

General Specifications

Purpose & Function

• 1. Prevent wheel lock-up
• When you brake hard, wheels can stop spinning while the car is still moving. The valve reduces pressure to keep them turning slightly, which maintains traction.

• 2. Maintain steering control
• Locked wheels = sliding. Sliding means you can’t steer. The valve helps keep grip so you can still turn the vehicle while braking.

• 3. Improve braking on slippery surfaces
• On wet, icy, or loose roads, it constantly adjusts pressure so each wheel grips as much as possible.

• 4. Optimize stopping performance
• Instead of one constant brake force, it rapidly increases and decreases pressure to achieve the best possible stopping distance in most conditions.

• 5. Balance braking at each wheel
• Each wheel may have different grip. The valve fine-tunes pressure individually so one wheel doesn’t lock before the others.

Signs of Bad ABS Hydraulic Brake Control Valve

Warning lights

• ABS light stays on

• Sometimes the traction control light comes on too
  This usually means the system detected a fault in the ABS unit (which includes the valve).

Unusual brake behavior

• Brakes locking up during hard braking (ABS not working)

• Or the opposite: brakes feel too soft or inconsistent

• Longer stopping distances

Pulsation issues

• Normally, ABS causes a slight rapid pulsing in the brake pedal during hard stops

• If the valve is bad, you might feel:

  • No pulsation at all (ABS not activating)

  • Or weird/constant pulsation even during normal braking

Uneven braking

• Vehicle pulls to one side when braking

• This can happen if the valve isn’t distributing pressure evenly to each wheel

Strange noises

• Clicking, buzzing, or grinding sounds from the ABS module area

• Some noise is normal during ABS operation, but constant or unusual sounds are not

Brake fluid issues

• Possible internal leaks in the valve

• Brake pedal may feel spongy or slowly sink

ABS not engaging when it should

• On slippery roads, wheels may lock up instead of being controlled

• Indicates the valve isn’t adjusting pressure properly

About International / Navistar

International, a brand of Navistar International Corporation, is a leading American manufacturer of commercial trucks, buses, and diesel engines. With a history dating back to the early 1900s, International is known for producing durable and reliable vehicles used in freight, construction, and municipal operations.

Navistar has built a strong reputation in the trucking industry by focusing on innovation, performance, and long-term dependability. Their vehicles and components are trusted by fleets and drivers across North America and beyond.