CATBrake Parts

8X6703 Valve-Relay — Cat 777

This relay valve is a key component in the air brake system, controlling the application and release of brakes by regulating air pressure. Manufactured to precise specifications, it ensures consistent and responsive braking performance, unlike a worn valve that may exhibit erratic behavior. Operators might notice delayed brake application, unintended brake release, or a loss of air pressure when this valve begins to malfunction.

Valve-Relay – Part No 8X6703 – CAT Spare Part
Part Specifications
BrandCAT
CategoryBrake Parts
ConditionAftermarket — OEM Specification
DispatchSame-day from Mumbai (before 3 PM IST)
GST InvoiceAvailable — all orders
Export DocsCommercial invoice, packing list, COO

Compatible Models

Always verify with serial number before ordering.

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Installation & Application Notes

Always replace brakes in axle sets. Bed-in new brake pads with 8–10 moderate stops from 40 km/h. Check disc runout with a dial gauge — maximum 0.1 mm. Inspect caliper slides and pistons when replacing pads.

Always consult the OEM service manual for model-specific torque values and procedures. WhatsApp our technical team if you need fitment guidance.

Part TypeAir Brake Relay Valve
MaterialAluminum, Rubber, Steel
ApplicationAir Brake System
Service LifeReplace as needed based on inspection
CompatibilityOEM specification
ConditionNew — OEM specification aftermarket

Failure Symptoms

The first symptom is often a noticeable delay in brake response or a 'soft' feel to the brake pedal. If left unaddressed, the valve may start to leak air, leading to reduced braking effectiveness or unintended brake release. Failure to address a malfunctioning relay valve can compromise the safe operation of the equipment by impairing its ability to stop reliably.

Installation Tip

Ensure all air lines are properly routed and securely connected to prevent kinks or leaks. It is critical to purge the air system of moisture and debris before connecting the new valve to prevent immediate contamination.

Service Note

Inspect air tanks, air dryers, and all air lines for leaks or damage, and check the condition of brake chambers and slack adjusters when replacing the relay valve.