Dongfeng GX rear left disc brake and chamber assembly 3502420-H18A0

The product features a space-optimized integrated structure that combines a heavy-duty disc brake caliper with a dual-chamber air actuator (service + parking brake chambers) into a single, cohesive unit. This design reduces component redundancy, minimizes installation time, and eliminates potential alignment issues between separate brake and air chamber components. The air actuator’s pushrod is directly coupled to the caliper’s lever mechanism via a precision-machined linkage, creating a short, rigid force transmission path that reduces response lag (≤ 0.3 seconds from air pressure input to brake pad engagement). Additionally, the compact layout avoids interference with the GX’s rear suspension arms, exhaust system, and wheel bearings, while simplifying routine inspection and maintenance

Brake Disc: Manufactured from high-carbon cast iron (HT250) with a ventilated, dual-ribbed structure. This material offers excellent thermal conductivity (≥ 52 W/m·K) and heat resistance, enabling efficient dissipation of heat generated during heavy braking (up to 650°C) to prevent thermal fade. The disc’s surface is precision-ground to a Ra ≤ 0.8μm finish, ensuring uniform contact with brake pads and reducing abnormal wear. It also features a corrosion-resistant zinc-plated hub mounting area to protect against rust from road salt and moisture.

Brake Pads: Composed of semi-metallic friction material (blended with iron fibers, copper particles, and high-temperature resin) with a stable friction coefficient of 0.38-0.45 (maintained across -30°C to 420°C). The pads include a built-in wear indicator—when the friction material is worn to 3mm, the indicator contacts the disc to produce a squealing sound, alerting users to replace the pads before metal-to-metal damage occurs.

Air Chamber: The chamber housing is made of lightweight, high-strength aluminum alloy (ADC12) to reduce unsprung weight, while the internal diaphragm uses nitrile rubber (NBR) with high tensile strength (≥ 18 MPa). This diaphragm withstands 150,000+ pressure cycles without cracking, ensuring leak-free operation. The chamber also includes a manual slack adjuster to compensate for brake pad wear, maintaining consistent pedal travel over the assembly’s service life

The integrated dual-chamber air actuator enables two critical braking functions tailored to Dongfeng GX’s operational needs:

Service Braking: The front (service) chamber activates when air pressure is applied via the vehicle’s brake pedal, pushing the pushrod to clamp the brake pads against the disc. It delivers a maximum braking force of 18-22 kN (depending on GX model), providing reliable stopping power for normal driving, highway cruising, and light cargo transport.

Parking/Emergency Braking: The rear (parking) chamber uses a pre-compressed steel spring to apply constant braking force when the vehicle is parked or in an emergency (e.g., air pressure loss). The spring force (≥ 25 kN) is strong enough to immobilize the GX on slopes up to 30° and can only be released by supplying air pressure to the chamber—complying with global safety regulations for commercial vehicle parking brakes. This dual-function design ensures independent redundancy, reducing the risk of brake failure

This assembly meets or exceeds international commercial vehicle braking standards, including China’s GB 7258 (Motor Vehicle Safety Technical Specifications), ISO 4194 (Automotive Disc Brakes), and ECE R13-H (UN Heavy-Duty Vehicle Brake Regulations). Each unit undergoes comprehensive pre-shipment testing:

Performance Testing: Dynamometer tests verify stopping distance (≤ 14.5m at 50 km/h) and thermal stability (friction coefficient decay ≤ 12% after 12 consecutive hard stops).

Air Tightness Testing: The air chamber is pressurized to 1.0 MPa and held for 45 minutes—pressure drop is limited to ≤ 0.015 MPa to ensure no leaks.

Durability Testing: 600,000+ simulated brake cycles (equivalent to 350,000+ km of real-world driving) confirm no component fatigue, pad/disc warping, or slack adjuster failure.

Environmental Testing: Salt spray exposure (1,200 hours), high-temperature cycling (80°C for 300 hours), and low-temperature storage (-40°C for 300 hours) validate corrosion resistance and performance stability in extreme conditions.

Backed by a 24-36 month manufacturer’s warranty, the assembly ensures long-term reliability for Dongfeng GX’s heavy-duty applications (e.g., long-haul freight, construction site transport)