3CX, 4CX
The Main Relief Valve (MRV) is the most important safety device in the loader's hydraulic system. It protects the pump and the entire system from damage due to a sudden pressure spike. If your machine is experiencing a loss of power across all loader functions, the hydraulics are very slow, or the oil is overheating, these are classic symptoms of a faulty MRV. A valve stuck open causes a constant loss of pressure, while one stuck closed risks bursting hoses or destroying the pump.
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Precise Pressure Setting
Reliable system protection
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High Durability
Resistant to pressure and vibrations
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Perfect Fit
"Plug & play" installation
The accuracy and quality of materials guarantee that the valve will open at the set pressure, ensuring long and trouble-free use.
The valve is fully adapted to work with original JCB valve blocks, ensuring a consistent repair.
The GX-AFTER brand is a proven and safe alternative that offers quality comparable to original parts at a much better price.
Before loosening any hydraulic component, you must relieve the pressure in the system by moving all controls several times with the engine off.
Before removing the old valve, thoroughly clean the area around it. Even the smallest contaminant entering the valve block can damage other valves or the pump.
Always install the valve with a new set of O-rings to ensure a 100% seal. Reusing old seals will likely cause a leak.
The valve is factory-calibrated to the correct pressure. You should not change its settings yourself without specialized pressure gauges.
Answer: Yes, this is the primary suspect. If all loader functions (lift, tilt, etc.) are weak, the most common cause is an MRV stuck in the open position. Other possibilities include a failed hydraulic pump or a clogged filter.
Question: What's the difference between this MRV and the ARVs on the sections?Answer: The MRV (Main Relief Valve) is the main safety valve that protects the entire system and pump. ARVs (Auxiliary Relief Valves) protect individual sections of the valve block (e.g., just the bucket tilt function).
Question: Can I "turn up" the pressure on this valve myself to increase power?Answer: This is extremely not recommended and dangerous. Increasing the pressure above factory standards leads to bursting hoses, damaged cylinders, and excessive load on the hydraulic pump, resulting in very expensive failures.
If you are unsure whether the selected product is suitable for your machine, contact us and we will help you choose the right part and provide practical advice in minutes.
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