Earthmoving Industry Insight, Reviews

Review: Sumitomo SH135X-3B excavator

This newly purchased Sumitomo SH135X-3B excavator is perfect for farm and forestry contracting.

Operator Andy Donald specced the excavator with a Wedgelock tilting hydraulic hitch, Chubb thumb and had the machine clad in a suit of armour comprising heavy-duty panels, guards and a ROPS frame.


Engine and maintenance

The Sumitomo SH135X-3B is powered by a three-litre 71kW Isuzu engine coupled to twin variable displacement hydraulic pumps. The four-cylinder diesel engine features common rail fuel-injection and a cooled EGR (exhaust gas recirculation) system, along with a turbo intercooler to reduce emissions and provide better fuel consumption by making a more efficient combustion cycle.

The hydraulic system requires less maintenance as the filter has a 2000-hour change interval and 5000 hours on hydraulic oil replacement. High-strength brass bushes are used in conjunction with hardened pins fitted with dust seals to prolong pin wear on the bucket and boom and only require greasing at 250 and 1000 hours respectively. Due to the tightly packaged components, access is fairly tight around the hydraulic pump and cooling system, though the filters have adequate room for routine servicing. 

Cab and controls

The Sumitomo SH135 is fitted with a very comfortable cab, the seat has plenty of adjustment and all the controls are easy to reach. Electrics are kept to a bare minimum, with no large display to be found. Instead, two small gauges indicate the fuel level and engine temperature and some warning lights are fitted under the right armrest. A couple of switches on the left console activate the work and power modes. A vent and cup holder occupy the space where you would normally find a large display screen – I know many will prefer the cup holder over some high-tech computer control.

Behind the seat is enough space for your lunch and jacket. With the seat back, there is plenty of legroom around the tracking pedals.

Visibility is reasonable, considering the front window is heavily guarded, and there is no window in the bottom of the door. This creates a small blindspot to the left of the cab.


Andy Donald chose to invest a considerable amount of money into guarding his new digger to reduce the risk of damage, as the Sumitomo will be working in some harsh conditions. Custom work included removing the factory panels and remaking them out of 5mm-thick sheet steel; the front right corner was also fully rebuilt to incorporate a large toolbox, which the standard machine lacked.

Modifications don’t stop there though, as the belly guard and travel motor covers were exchanged for heavier-duty steel. A rather strong-looking ROPS and FOPS frame encases the cab and provides a super safe office for the operator. Extra lights were fitted and the digger now weighs just over 16 tonnes. The operators have done a stunning job transforming the Sumi into a bullet proof machine fit for more than just the bush.

Performance and handling

Donald was working the Sumi in a forestry block repairing logging tracks when I visited. The rain was holding off but previous bad weather had made the conditions slippery once off the gravel tracks.

Inside the cab, I was greeted by a basic but pleasant interior and I found the Sumitomo very comfortable and easy to operate. Its basic control switches mean that there is no scrolling through complicated displays to set the machine up how you want it.

I started by clearing a slip and shaping the road. This is where the Wedgelock tilt hitch comes in very useful. With up to 70° tilt each way, there is enough movement to batter very steep banks.

The tilt is controlled by two buttons on the right joystick. A third button diverts the tilt oil to the thumb. For fine control, this circuit can also be operated by the foot pedal but by using the buttons, the machine can be easily tracked while tilting the bucket.

The SH135 has good operating characteristics and very smooth hydraulics, both while moving fast and during fine movements. The wide bucket fitted at the time had a deep profile and a large capacity. With a heaped bucket of wet clay and the combined weight of the tilt hitch and Chubb thumb, the excavator remained stable during operation, although at full reach over the side, the weight did become noticeable.

Good speed and power gives the digger quick cycle times and with the cab door closed, noise levels aren’t intrusive.

Tracking performance is strong and smooth and the excavator combines all functions well. I walked the machine off the track and down a hill, where there was a bank to climb. Assisting with the arm, I attempted the climb. The arm pulls well while tracking and the SH135 began to ascend, but due to the slippery ground conditions, as soon as I released the bucket for another bite the digger slid and I was back where I started. A couple of attempts later and I succeeded, but only because of the good oil distribution to all functions.

What I like about this machine is that it performs well and is specced to take on virtually anything. Donald hasn’t just stuck with the norm, he’s set up his digger exactly how he wants it and now has a very versatile machine that will stand the test of time.

Photography: Tim Dittmer

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