• By Byte Market Editorial

Kubota Excavator Controls: ISO vs SAE and What to Check Before Digging

In the common ISO excavator pattern, the left joystick controls the arm and the right joystick controls the boom. In the common SAE backhoe pattern, those forward-and-back functions exchange hands. Swing and bucket curl/dump stay on the same hands in the comparison below.

That is the difference most operators mean when they ask about ISO versus SAE controls. Before using an unfamiliar Kubota, match the machine's decal, selector and manual. A pattern name is not proof of the machine's current setting.

ISO vs SAE: what each joystick does

“Forward” and “back” below describe joystick movement from the seated operator's position. The chart concerns the digging controls, not the travel levers, dozer blade or auxiliary attachment switches.

The comparison corresponds to the two patterns illustrated in Kubota's U17-3 operator manual, printed pages 31–32. In that edition, Pattern A matches the SAE arrangement above; Pattern B matches ISO. Treat that A/B mapping as an example for the cited document, not a universal rule for every Kubota selector.

Boom, arm and bucket: avoid a terminology mix-up

The boom is the section connected to the machine's upper structure. The arm, also called the stick or dipper, is the next section, between the boom and bucket. Curling the bucket changes its angle at the end of the arm.

That vocabulary is useful when reporting a control problem. “The left stick lifts” can mean either the joystick or the excavator arm. “Pulling the left joystick back raises the boom” describes an observable action and removes the ambiguity.

Do not interpret “arm out” as a promise that the bucket follows a perfectly horizontal line. It identifies the controlled joint. The bucket's path also depends on the position of the other joints.

Is SAE the same as backhoe controls?

In this comparison, “SAE backhoe pattern” is the alternative joystick arrangement. Kubota itself uses that wording in its KX057-4 brochure, which describes TPSS selection between ISO and SAE backhoe patterns.

The name does not mean every backhoe has identical controls, or that an excavator must be operated in ISO. It also does not identify a selector's physical location. The KX057-4 brochure describes an under-seat selector; a different model needs its own instructions.

If a rental handover uses names such as “excavator controls” or “backhoe controls,” ask for the corresponding diagram. If it uses brand nicknames, translate them into the actual boom-and-arm assignments. A diagram is a much clearer agreement between operators than “the normal pattern.”

How do you change the control pattern on a Kubota?

First establish that the machine has a manufacturer-provided pattern selector. Find the TPSS or pattern-change section in the applicable operator manual. Do not assume a switch shown in a video belongs to the same model, market or configuration.

The cited U17-3 manual instructs the operator to learn both patterns, select the familiar one and become accustomed to the selected response slowly. Its selector illustration and A/B chart should be read together.

Use the complete model-specific procedure to park, secure the attachment, change the selector and return the machine to operation. Then verify the response in the prescribed clear area before beginning productive work. If the decal, selected position and actual response disagree, stop and have the discrepancy resolved. Do not try to make the machine “match the picture” by experimenting with hydraulic hose connections.

The pattern selector is not the hydraulic safety lock

A pattern selector determines which digging function a control requests. The hydraulic isolation device is used to prevent unintended operation in the situations specified by the manufacturer. They answer different questions.

The HSE's excavator isolation safety bulletin describes a fatal incident involving unintended movement and stresses correct use of the isolation device. Changing to a familiar pattern does not remove the need to isolate the controls before an approach or other activity requiring isolation.

For site planning, the HSE's excavator guidance also addresses exclusion, visibility and operator competence. The machine's operating manual supplies the actual control procedure.

A better handover for a shared or hired machine

Leave the next operator a short factual record. It need not be a long form.

Take reference photos while the machine is safely parked and secured. A handover note helps the next operator prepare; it does not replace that operator's familiarisation or the site's procedures.

When the question becomes a repair problem

Choosing between two correctly functioning patterns is an operating question. A selector that cannot be secured, controls that do not match the decal, or movement inconsistent with the selected pattern needs a service investigation.

For a U17 or U17-3, the Kubota workshop manual 97899-61970 listed on Byte Market provides hydraulic and electrical reference material. Check the publication's model and version coverage and the relevant contents before ordering. Start with the operator manual for normal pattern selection; use workshop documentation when qualified service work is required.

Prepared by Byte Market Editorial using the manufacturer documents and safety guidance linked above. The illustrations explain the comparison; they are not replacement machine decals.