723-30-50101 Main Relief Valve is an aftermarket replacement main relief valve for Komatsu machines, including PC120-6, PC130-6 and other listed models. A relief valve limits the maximum pressure in a hydraulic circuit. It is supplied by LIONKITS as aftermarket new with a 3-month warranty.
723-30-50101 Main Relief Valve Specifications
- Product Type: Main Relief Valve
- Part Number: 723-30-50101
- Compatible Brand: Komatsu
- Condition: Aftermarket new
- Warranty: 3 months
- Brand: LIONKITS
- Country of Origin: China
Komatsu Models Compatible with the 723-30-50101 Main Relief Valve
- PC120-6
- PC130-6
Your model is not listed? Contact LIONKITS via live chat or email with your machine model and nameplate photo, and we will confirm compatibility.
What Does a Hydraulic Relief Valve Do?
A relief valve limits the maximum pressure in a hydraulic circuit. When pressure reaches the set value, the valve opens and releases excess oil to the tank, which protects the pump, hoses, motors and cylinders from overload. The main relief valve sets the pressure for the whole system, while circuit reliefs such as swing, travel or auxiliary reliefs protect individual functions.
Signs the Valve Needs Replacing
- Weak power and slow movement: the machine struggles with loads it used to handle, because the relief valve opens too early or leaks.
- Low or unstable system pressure: a gauge at the test port shows low or fluctuating pressure; if the main relief is weak, every function is weak.
- Noise or vibration: unusual noise or shaking in the hydraulic system can point to a worn or damaged relief valve.
- Overheating oil: oil that keeps bypassing across a leaking relief heats up quickly.
These symptoms overlap with worn pumps, dirty oil and clogged filters, so check the basics and measure pressure before replacing the valve.
How to Order and Install the 723-30-50101 Main Relief Valve
- Confirm your machine model, engine model and the part number on your existing valve before ordering.
- Send a photo of the nameplate or the old valve if you are not sure; LIONKITS will confirm fitment for you.
- Check the set pressure with a pressure gauge at the test port after installation, and adjust it to the specification in the service manual.
- Clean the valve bore and replace the hydraulic oil filters; contaminated oil is a common cause of sticking relief valves.
- Replace the O-rings and keep the valve free of dirt while it is out of the machine.
Shipping, Payment and Support
- Delivery time: 3-7 days.
Prepare time: 2-3 days - Shipping methods: DHL, FedEx, UPS, TNT, USPS EMS
- Payment methods: PayPal, Stripe, Credit card, Visa
- Order tracking: A tracking number with a tracking link is sent by email once the order ships.
Frequently Asked Questions
What is the 723-30-50101 Main Relief Valve?
The 723-30-50101 Main Relief Valve is an aftermarket replacement main relief valve for Komatsu machines, supplied as aftermarket new under part number 723-30-50101.
Which Komatsu models does the 723-30-50101 Main Relief Valve fit?
It is listed for PC120-6, PC130-6 and other models in the compatibility list above. If you are unsure, send your machine nameplate to LIONKITS for confirmation.
How do I know a relief valve has failed?
Typical signs are weak hydraulic power, slow movements, low or unstable pressure at the test port, unusual noise or vibration and oil running hot.
What are the warranty and delivery terms for the 723-30-50101 Main Relief Valve?
Warranty: 3 months. Typically, delivery takes 3-7 days.
Prepare time: 2-3 days. Shipping by DHL, FedEx, UPS, TNT, USPS EMS.



















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