MH031742 BRAKE FLEX AIR HOSE AIR GOVERNOR VALVE L = 300MM FM657 FK618

MH031742 BRAKE FLEX AIR HOSE AIR GOVERNOR VALVE L = 300MM FM657 FK618 

1. Quick Notice

Please verify the OEM part number MH031742, overall length (300mm), fitting type, and thread size before ordering. This flexible air hose is designed for the air governor or brake system air signal lines on compatible Mitsubishi Fuso trucks. Ensure your vehicle is equipped with a pneumatic air brake system. Improper fitment may cause air leaks or governor malfunction. Installation must be performed by a qualified commercial vehicle technician. We are not responsible for incorrect fitment or damage due to misapplication.

2. Description

This is a direct replacement flexible brake air hose / air governor signal line for Mitsubishi Fuso trucks. The part number MH031742 is typically used to connect the air governor to the compressor or reservoir for unloader signal control. It may also serve as a brake chamber or valve control line in pneumatic air brake systems. Constructed with reinforced synthetic rubber and braided textile or steel wire layers, this hose resists pressure pulses, heat, ozone, and road chemicals. The total length is 300mm from fitting to fitting. Designed specifically for Fuso FM657 and FK618 chassis with air brake systems. Replacing worn or leaking plastic or rubber air lines restores proper governor cut-in / cut-out timing and brake response.

3. Parameters Table

4. Custom Content

Why Replace Your Brake Flex Air Hose?

Plastic or rubber air lines become brittle, cracked, or chafed over time. A failed governor signal hose will cause the air compressor to run continuously (no unload) or fail to build pressure. For brake chambers or valves, a leaking flex hose results in slow brake release, pressure drop, or complete brake failure on one axle.

Installation Tip:

• Always drain all air tanks before disconnecting any air line.

• Use two wrenches when tightening the fitting (one to hold the hose fitting, one to tighten the nut) to prevent twisting the hose.

• Do not overtighten. Hand-tight plus 1/4 turn is usually sufficient for tapered threads. For straight thread fittings, use new sealing washers or O-rings.

• Route the new hose away from exhaust pipes, sharp edges, and moving suspension parts.

• After installation, pressurize the system and apply soapy water to all connections. No bubbles allowed.

• Perform a full air brake system function test before returning the vehicle to service.

 

5. FAQ 

Q1: Is MH031742 a genuine Mitsubishi Fuso part?
A1: This listing is for a high-quality aftermarket replacement that meets or exceeds OE specifications. It is not a genuine Mitsubishi part unless explicitly stated otherwise, but it is designed as a direct replacement for the original hose.

Q2: Which truck models use this 300mm brake flex hose?
A2: This hose is specifically listed for Mitsubishi Fuso FM657 and FK618. It may also fit other Fuso medium and heavy trucks with the same governor location and port spacing. Always compare your original hose length, fittings, and thread sizes.

Q3: Is this hose for the air governor or for a brake chamber?
A3: The MH031742 part number is commonly used for the air governor signal line (compressor unloader control). However, the same specification hose can also serve as a brake chamber or valve flex line. Check your original application before ordering.

Q4: What fittings are on this hose?
A4: This hose comes with pre-crimped metal fittings on both ends. Common configurations include straight fittings, 90-degree elbow fittings, or one of each. Please refer to the product photos and measure your original hose fitting angles before purchasing.

Q5: Can I use this hose for any other fluid?
A5: No. This hose is designed for compressed air only in truck air brake or governor systems. Do not use for diesel fuel, coolant, oil, or hydraulic fluid.

Q6: What is the inside diameter of this hose?
A6: The inner diameter is typically 6mm or 8mm depending on the production batch. Most Fuso governor signal lines use 6mm ID. Check your original hose ID or thread size to confirm compatibility.

Q7: Why does my air compressor run constantly after replacing the governor but not this hose?
A7: If the old signal hose is cracked or blocked, the governor cannot sense system pressure. Even with a new governor, a failed MH031742 hose will cause continuous running or no pressure buildup. Replace the hose first.

Q8: How do I test if this hose is leaking after installation?
A8: Build system pressure to cut-out (approx 120-130 psi). Apply soapy water or leak detection spray to both fittings and along the hose body. Any growing bubbles indicate a leak. Also listen for hissing sounds with the engine off.

Q9: Does this hose come with new sealing washers or O-rings?
A9: No. The hose includes pre-crimped fittings but does not include separate sealing washers, copper gaskets, or O-rings unless specified in the listing title. Reuse original seals if in good condition or purchase new ones separately.

Q10: What is your return policy if the length or fittings do not match?
A10: Unused, uninstalled hoses can be returned within 30 days in original packaging. Please contact us first with photos of your original hose (length, fitting angles, thread size) for fitment confirmation before returning.