The Braking device – Brake main valve and combination pedal is the central control unit for the pneumatic braking system on the HOWO MAX 4X2 tractor, integrating the brake pedal, master brake valve, and all associated mounting hardware. This Braking device – Brake main valve and combination pedal kit ensures precise, responsive braking with reliable modulation and fail‑safe operation. When you choose authentic Howo Parts, this Braking device – Brake main valve and combination pedal guarantees OE fitment and superior braking performance. Below are detailed descriptions of every component included with this Braking device – Brake main valve and combination pedal assembly.
The combination pedal assembly is the driver’s primary brake input device, incorporating the brake pedal, linkage, and return spring. This Braking device – Brake main valve and combination pedal component is fabricated from high‑strength steel with corrosion‑resistant coating. The pedal geometry is ergonomically designed for reduced driver fatigue, and the integrated return spring ensures immediate pedal release.
The assembly includes a mounting bracket that positions the pedal correctly relative to the driver’s foot. The pedal arm is fitted with a wear‑resistant rubber pad for secure foot grip. This Braking device – Brake main valve and combination pedal component transmits the driver’s foot force to the master brake valve via a mechanical pushrod or cable. It is critical for accurate brake modulation.
Eight large washers are used to distribute clamping load under bolt heads or nuts in the Braking device – Brake main valve and combination pedal assembly. These washers are made from hardened steel with a zinc‑nickel coating.
The large outer diameter provides a wide bearing surface on aluminium or cast iron components, preventing embedding and maintaining clamp force. Correct placement of these washers in the Braking device – Brake main valve and combination pedal ensures even stress distribution and reduces the risk of cracking.
Fourteen M8 hex flange nuts (12 + 2) are used to secure various components of the Braking device – Brake main valve and combination pedal, including brackets, valve mounts, and air line fittings. These nuts feature an integral flange that acts as a built‑in washer, distributing load and preventing loosening. They are grade 8 with a zinc‑phosphate coating. Torque these Braking device – Brake main valve and combination pedal nuts to 25 Nm. The flange design eliminates the need for separate washers in most applications.
The master brake valve is the pneumatic control valve that modulates air pressure to the brake chambers based on pedal input. This Braking device – Brake main valve and combination pedal valve features a differential pressure (Δp) of 0.3 bar, providing fine control over brake application.
It is a two‑circuit valve that supplies separate air signals to the front and rear axles, ensuring balanced braking. The valve is made from corrosion‑resistant aluminium with internal seals rated for 12 bar maximum pressure. It includes a built‑in relay function for fast response and a manual override for emergency use. A properly functioning master brake valve is essential for the Braking device – Brake main valve and combination pedal system.
Four flat washers (Q401B08F31) are used in the Braking device – Brake main valve and combination pedal to provide a smooth bearing surface under bolt heads. These washers are made from hardened steel with a zinc coating. They are typically used together with spring washers to prevent fastener loosening. Correct placement ensures that the clamping load is evenly spread and does not damage the mounting surfaces.
Four spring washers are supplied to provide vibration‑resistant locking for the Braking device – Brake main valve and combination pedal fasteners. These split‑coil washers are made from spring steel with a phosphate coating. They are installed between the bolt head and the flat washer to maintain tension and prevent loosening under the severe vibration of a heavy truck. The spring washer is a critical component for ensuring the long‑term integrity of the Braking device – Brake main valve and combination pedal.
Four nut holders NG12 are retainers that hold the hexagon nuts in position during the assembly of the Braking device – Brake main valve and combination pedal pneumatic connections. They are spring steel clips that grip the nut, preventing it from rotating while tightening the joint. These nut holders are essential for assembling the NG12 air line fittings used in the Braking device – Brake main valve and combination pedal, ensuring a leak‑free connection without the need for additional tools.
Four circlips NG12 are retaining rings used to secure components such as the nut holders or other fittings in the Braking device – Brake main valve and combination pedal air system. These external circlips are made from spring steel and are installed into a groove on the joint body to prevent axial movement. They ensure that the nut holders remain in place, maintaining the integrity of the pneumatic connections.
Four elastic elements NG12 are rubber or spring‑loaded components that provide vibration damping and preload for the Braking device – Brake main valve and combination pedal fasteners. These elastic elements reduce the transmission of road vibration to the master brake valve and pedal assembly, extending service life and maintaining consistent brake feel. They also help to seal the pneumatic connections by maintaining slight pressure on the fittings.
Two ejector housings are provided (material encodings YZ952536000017 and YG9525360012) as part of the Braking device – Brake main valve and combination pedal assembly. These housings are aluminium castings that mount the ejector mechanism used to assist with pedal return or to provide a tactile feedback to the driver. The ejector housing contains a spring‑loaded plunger that pushes the pedal back when released, ensuring a positive pedal feel and rapid brake release. Correct installation of the ejector housing is vital for the proper operation of the Braking device – Brake main valve and combination pedal.
Two straight‑through next joint bodies with NG6 port and M16x1.5 thread are used to connect air lines to the Braking device – Brake main valve and combination pedal.
These fittings are made from nickel‑plated brass and provide a straight‑through passage for air. They are equipped with O‑ring seals and are compatible with standard air brake tubing. The M16x1.5 thread is used for the valve ports, while the NG6 side connects to the air lines. Properly torqued fittings are essential to prevent air leaks in the Braking device – Brake main valve and combination pedal.
Two thin hexagon nuts with M16x1.5 thread are used to secure the straight‑through joint bodies to the master brake valve. These Braking device – Brake main valve and combination pedal nuts are made from zinc‑plated steel and are torqued to 30 Nm. Their thin profile allows clearance in tight spaces. They are used in conjunction with the external teeth serrated lock washer to prevent loosening.
Two external teeth serrated lock washers are used under the hexagon thin nuts on the Braking device – Brake main valve and combination pedal. These washers have sharp serrations that bite into the nut and the mating surface, providing positive locking against vibration. They are made from hardened spring steel and ensure that the pneumatic fittings remain securely fastened even under severe chassis vibration. Correct orientation is important: the serrations must face the nut.
Braking device – Brake main valve and combination pedal – genuine HOWO complete brake control kit for MAX 4X2
This Braking device – Brake main valve and combination pedal kit includes the pedal assembly, master brake valve, all mounting hardware, and pneumatic fittings. No extra parts are needed for a full installation of the Braking device – Brake main valve and combination pedal.
The master brake valve in this Braking device – Brake main valve and combination pedal provides a differential pressure of 0.3 bar, ensuring smooth and progressive brake application. This Braking device – Brake main valve and combination pedal valve is engineered for reliability and fast response.
The Braking device – Brake main valve and combination pedal uses spring washers, serrated lock washers, and nut holders to secure all connections. This Braking device – Brake main valve and combination pedal hardware ensures that fasteners remain tight under severe chassis vibration.
The straight‑through joint bodies, hex thin nuts, and elastic elements in this Braking device – Brake main valve and combination pedal kit are matched to the NG6 and NG12 air line standards, guaranteeing leak‑free connections and consistent air flow.
The Braking device – Brake main valve and combination pedal converts the driver’s foot pressure into pneumatic control signals. When the pedal is pressed, the mechanical linkage actuates the master brake valve. The valve proportions the air pressure from the reservoirs and delivers it to the front and rear brake chambers via the air lines. The differential pressure (Δp=0.3) ensures that the valve output pressure is slightly lower than the input, providing fine control.
The ejector housing provides a positive pedal return and tactile feedback. The nut holders, circlips, and elastic elements secure the air fittings and prevent vibration‑induced loosening. The large washers, flat washers, and spring washers distribute clamp loads and maintain fastener tension. The result is a responsive, reliable braking system that meets the demanding safety requirements of heavy‑duty trucking. Regular inspection and maintenance of the Braking device – Brake main valve and combination pedal are essential for safe operation.
Before installing the Braking device – Brake main valve and combination pedal, depressurise the air system and disconnect the battery. Remove the old pedal and valve. Install the combination pedal assembly onto the firewall bracket using the large washers, M8 flange nuts, and spring washers (torque 25 Nm). Install the master brake valve onto its bracket using the same fasteners, ensuring that the valve is oriented with the ports facing the correct direction. Connect the air lines to the valve ports using the straight‑through joint bodies, hex thin nuts, and serrated lock washers (torque 30 Nm).
Secure the nut holders and circlips onto the fittings to lock them in place. Install the elastic elements under the mounting bolts to reduce vibration. Install the ejector housings onto their respective mounts using the provided fasteners. Reconnect the pneumatic lines and the electrical connector (if fitted). Pressurise the system and check for leaks. Test the pedal travel and brake application. The Braking device – Brake main valve and combination pedal is now ready for service.
If the brake pedal feels spongy or has excessive travel, air may be trapped in the system or the master brake valve may be faulty. Bleed the air lines and check the valve for correct function. If the brakes drag or do not release fully, the return spring in the ejector housing may be weak or the pedal linkage may be binding.
Inspect the ejector housing and lubricate the pedal pivot. Air leaks from the fittings indicate loose nuts or damaged seals. Retorque the hex thin nuts and replace O‑rings if necessary. If the Braking device – Brake main valve and combination pedal produces a hissing sound, inspect the master brake valve for internal leakage; replace the valve if defective. Always use genuine HOWO parts for repairs.
Inspect the Braking device – Brake main valve and combination pedal at every scheduled service (every 50,000 km). Check the pedal movement for smooth operation and adequate free play. Inspect the master brake valve for oil contamination or external damage. Tighten any loose fasteners. Check the air fittings for signs of leakage using soapy water.
Replace the ejector housing springs if they show signs of fatigue. Lubricate the pedal pivot with lithium grease. Keep the area around the Braking device – Brake main valve and combination pedal clean and free from debris. A well‑maintained braking device ensures safe and reliable stopping performance.
This Braking device – Brake main valve and combination pedal kit is specifically designed for the HOWO MAX 4X2 tractor, compatible with all production years from 2018 onward. It is also suitable for SITRAK C7H and HOWO T7H models with the same cab layout. The master brake valve with Δp=0.3 is the standard spec for these vehicles.
The NG6 and NG12 fittings are compatible with the air line sizes used in these trucks. This Braking device – Brake main valve and combination pedal kit is not compatible with older WD615 or A7 models, which use different pedal geometries and valve types. Always verify your vehicle’s brake system type before ordering.
Aftermarket Braking device – Brake main valve and combination pedal components may have incorrect pedal ratios, leading to excessive effort or poor modulation. Non‑genuine master brake valves may have incorrect differential pressure settings, causing uneven brake application. Generic fasteners can loosen under vibration, leading to loss of control.
The air fittings in copy kits may leak, resulting in gradual air loss and eventual brake failure. Genuine HOWO Braking device – Brake main valve and combination pedal components are manufactured to SINOTRUK’s exact specifications, using validated materials and precise calibration. The small additional cost of a genuine Braking device – Brake main valve and combination pedal is negligible compared to the safety risk of a compromised brake system.
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