SK330-8 and SK350-8: The 30-Tonne Hydraulic System Read As One Machine

An SK330-8 or SK350-8 is not a stretched SK200-8. The 33 to 35 tonne class runs a different pump family, a different swing family and a different valve block, and the moment an order is placed from the model name alone those differences produce the wrong part. Guangzhou Shenyue Machinery Technology Co., Ltd. has supplied the big Kobelco class since 2007, and this guide reads the 30-tonne hydraulic system as one machine rather than as a list of parts.

Where the 30-tonne class stops sharing

The 20-tonne class is built around the K3V112DT pump family and the M5X130 swing family; the 30-tonne class moves up to the K5V140 pump family and the M5X180 swing family. That is not a trim difference. Displacement, regulator setting, control curve and the physical size of the mounting all change with the class, so a pump or swing assembly bought for a 20-tonne machine will not fit a 33-tonne machine however similar the numbers look on a quotation. The same rule runs down the chain: the bigger class carries heavier travel motors, heavier hose and heavier cylinder rods, and each of those changes the number.

The pump is the centre of the system

Everything downstream is sized around the pump. The K5V140 family feeds a heavier machine with a longer reach, so the relief settings, the flow to the travel circuit and the swing priority all sit on a different curve from the 20-tonne K3V112DT. When a 30-tonne machine feels weak, the honest first check is not the pump itself but the regulator and the control curve: a pump of the right family fitted with the wrong setting performs exactly like a tired pump, and that is how the operator reports it. Read the component nameplate on the pump before deciding the family is wrong.

Swing is where the big class is easiest to get wrong

The SK330-8 class and above use the M5X180 swing motor, quoted in our records as LC15V00022F1. That is a different size class from the M5X130 motors fitted to SK200-8 and SK210-8 machines, whose numbers are YN15V00077F1, YN15V00055F1 and YN15V00035F1. Because both are described simply as a swing motor on an enquiry, this is one of the most common wrong-part risks in the big class — the numbers look plausible and only the mounting disagrees. Swing reduction and swing bearing numbers follow the machine rather than the family, and they change again where a long undercarriage is fitted.

The valve block ties it together

The 30-tonne control valve carries more sections and larger spools than the 20-tonne block, and our site's video library shows the big-class block under the number LC30V00028F5. If a function on a 33-tonne machine is sluggish or unresponsive, the valve block, the relief settings inside it and the pilot supply that strokes it have to be checked as one system, because each of them can produce the same symptom and each costs a very different amount to put right. Our hydraulic components range holds the pump, swing and valve families for both classes, and the SK330 and SK350LC pages set out the machines themselves.

The three numbers that decide the order

Three numbers settle almost every 30-tonne enquiry: the machine serial, which the parts catalogue is indexed by; the component nameplate, which catches supersessions and class changes; and the hydraulic setting, where a regulator or relief value has to match the machine's duty rather than the family. Any number that cannot be confirmed from our records is quoted as commonly quoted, with the nameplate treated as the authority. Our part number search is the quickest way to check a number before it reaches a quotation.

How we supply

Guangzhou Shenyue Machinery Technology Co., Ltd. has specialised in Kobelco since 2007, with 4 warehouses over 1000 m² in Guangzhou, 3,000+ part types on the shelf and 100,000+ part numbers available to order through original supply channels. Shenyue is an independent supplier and is not an authorized dealer of Kobelco Construction Machinery Co., Ltd.; for Kobelco, Hino, Isuzu, Yanmar, Cummins, Kawasaki, Nabtesco, KYB and KPM we supply genuine parts ordered through original supply channels alongside quality replacement alternatives, at prices close to agent level, and the five brands we hold formal authorization for — Mitsubishi, Garrett, TONGMYUNG, Marusan and NIKURA — are named on every quotation. Published Kobelco machine data is a useful cross-reference when a class change has to be pinned to a build year.

Frequently Asked Questions

Is the K5V140 pump the same as the K3V112DT fitted to an SK200-8?

No. They are different pump families in different size classes. The K3V112DT serves the 20-tonne class and the K5V140 family serves the SK330-8 and SK350-8 class, with different displacement, regulator settings and mounting. Ordering across the classes from the model name alone is the most common source of a wrong pump.

Which swing motor does an SK330-8 use?

The SK330-8 class and above use the M5X180 swing motor family, quoted in our records as LC15V00022F1. That is a larger class than the M5X130 motors fitted to SK200-8 and SK210-8 machines, so the two are not interchangeable even though both are called a swing motor and both mount in the same place.

Why does my SK350-8 still feel weak after a pump replacement?

Usually the regulator setting rather than the pump. A pump from the correct family fitted with the wrong control curve or relief setting behaves exactly like a tired pump. Confirm the setting against the machine's duty and read the component nameplate before ordering anything else.

What should I send for a 30-tonne Kobelco parts quote?

The machine plate with the full designation and serial, a photograph of the component nameplate on the pump, swing motor or valve being replaced, and the current hour meter reading. Guangzhou Shenyue Machinery Technology Co., Ltd. confirms the family and class and declares every line's grade before quoting.