707-03-00340 Komatsu D375A-6 Blade Lift Cylinder Aftermarket Replacement

Product Overview

SEIGO’s aftermarket blade lift cylinder, part number 707-03-00340, is a direct drop-in replacement for the Komatsu D375A-6 crawler bulldozer — a roughly 70-tonne class machine used for heavy dozing, mine overburden stripping and large-scale earthworks. The blade lift cylinders raise and lower the dozer blade, and the D375A-6 is fitted with two of them, one on each side of the blade frame. They work as a pair through every dozing pass, carrying the blade weight plus the reaction load generated when the blade is loaded into the cut.

Komatsu catalogues this cylinder in the blade lift group alongside the closely related numbers 707-03-00341, 707-03-00350 and 707-03-00351, which cover the paired and revision variants of the same blade lift position. On earlier D375A generations (D375A-1 through -5) the blade cylinders carried 195-63 series numbers; the 707-03 series applies to the D375A-6. Confirming the machine generation from the serial number is therefore the first step in ordering the correct cylinder, since the D375A designation alone spans several incompatible cylinder series.

A blade lift cylinder on a large dozer fails from a specific combination of loads: sustained weight-holding when the blade is carried, shock loading when the blade strikes rock or the machine tramming over rough ground, and heavy abrasive contamination from the dozing environment driving grit against the rod. SEIGO manufactures the 707-03-00340 to address all three — a 42CrMo4 induction-hardened, hard-chrome-plated piston rod finished for abrasion and impact resistance, an ST52 seamless honed steel barrel, and a genuine NOK (Japan) or Parker (USA) seal kit with a heavy-duty wiper for the high-contamination blade environment. Every unit is pressure tested at 1.5× rated working pressure before shipment from our Guangdong factory and is backed by a 12-month or 2,000 operating-hour warranty. Standard lead time is approximately 30 days ex-works, with expedited production available for machine downtime.

Product Specifications

* OEM part numbers, brand names and model designations are used for identification and cross-reference purposes only. SEIGO Machinery is an independent aftermarket manufacturer and is not affiliated with Komatsu Ltd.

Komatsu D375A-6 Blade & Ripper Cylinder Cross-Reference

The D375A-6 uses the 707-03 and 707-G3 / 707-01 cylinder series across the blade and ripper work equipment. Part 707-03-00340 is the blade lift cylinder. Related numbers within the same group are listed below.

Related numbers are listed for cross-reference within the D375A-6 blade lift group. The exact number for your machine depends on serial number and blade configuration — confirm before ordering. SEIGO supplies all blade and ripper cylinder positions for the D375A platform.

Komatsu D375A Generations — Different Cylinder Series

The D375A designation covers several generations built over more than two decades, and the blade cylinder part numbers changed between them. Ordering by machine model alone is unreliable — the generation, identified from the serial number, determines the correct cylinder series.

The 195-63 and 707-03 series are not interchangeable. If your D375A is an earlier generation, the 707-03-00340 will not fit — send us your full machine serial number and we will identify the correct blade cylinder for your generation. SEIGO manufactures blade and ripper cylinders across the full D375A range.

Why This Cylinder, Specifically

• Correct generation, verified. The D375A-6 uses the 707-03 series; earlier D375A machines use the 195-63 series, and the two do not interchange. We confirm the generation against your serial number before quoting, because ordering by model name alone is the most common source of wrong-part orders on this dozer.
• Built for the blade duty cycle. A blade lift cylinder holds sustained load when the blade is carried and takes shock when the blade strikes rock. We dimension the rod for that combination and finish the chrome for impact resistance — the failure mode here is rod scoring and wiper failure from contamination, not work-pressure seal blow-by.
• Contamination-rated wiper. A dozer works in the dirtiest environment of any earthmoving machine, with grit driven against the rod on every stroke. We fit a heavy-duty wiper package specifically for this, because contamination ingress past a worn wiper is what destroys the primary seal and scores the rod.
• Replace as a pair. The D375A-6 runs two blade lift cylinders that accumulate identical hours. If one is leaking or scored, the other is usually close behind — replacing the pair in one shutdown keeps blade lift balanced and avoids a second unplanned stoppage. We supply matched pairs on a single order.
• Rods, barrels and seal kits supplied separately. For workshops rebuilding in-house, we supply the piston rod, honed barrel, cylinder head, piston and seal kit as individual items — typically 40–60% of the cost of a complete cylinder. Send us your machine serial number and the component you need for a quotation.
• Full traceability and testing. ISO 9001:2015 manufacturing, 100% pressure tested at 1.5× rated working pressure, shipped in an ISPM-15 fumigated export crate with material certificate and test record.

FAQ

Q1: What position is 707-03-00340 on the D375A-6?

A: It is the blade lift cylinder — the cylinder that raises and lowers the dozer blade. The D375A-6 is fitted with two of them, one on each side of the blade frame. Related numbers 707-03-00341, 707-03-00350 and 707-03-00351 cover the paired and revision variants of the same blade lift position.

Q2: Will 707-03-00340 fit an older D375A (D375A-3 or D375A-5)?

A: No. Earlier D375A generations use the 195-63 cylinder series, which is not interchangeable with the 707-03 series used on the D375A-6. Because the D375A model name spans several incompatible generations, always confirm the machine generation from the serial number before ordering rather than relying on the model designation. Send us your serial number and we will identify the correct blade cylinder for your machine.

Q3: Should I replace both blade lift cylinders at the same time?

A: In most cases, yes. The two blade lift cylinders share identical operating hours and wear at a similar rate. If one has failed or is showing rod scoring or seal weeping, the other is usually close behind. Replacing the pair in a single planned shutdown keeps blade lift balanced across the frame and avoids a second unplanned stoppage. SEIGO supplies matched pairs on one purchase order.

Q4: What are the warning signs of a failing blade lift cylinder?

A: Watch for the blade drifting down when held raised with the control in neutral, slow or uneven blade lift under load, hydraulic oil weeping at the rod gland, and visible scoring, pitting or chrome loss on the exposed rod. On a dozer, rod damage from contamination is the leading initiator of failure, so inspect the rod surface as well as the seals.

Q5: Can I buy the rod, barrel or seal kit separately instead of a complete cylinder?

A: Yes. SEIGO manufactures the piston rod, honed barrel, cylinder head, piston and seal kit as individual items and supplies them to hydraulic repair shops and rebuild facilities. For workshops with in-house honing and assembly capability, sub-component supply typically runs 40–60% of the cost of a complete replacement cylinder. On blade lift cylinders, rod and wiper-seal replacement is the most common single-item order. Send us your machine serial number and the component you need for a quotation.

Q6: What is the lead time and how does it ship?

A: Standard production lead time is approximately 30 days ex-works Guangdong, China, with expedited production available for machine downtime. Each cylinder ships in an ISPM-15 fumigated wooden export crate, FOB Shenzhen, CIF or DDP. Sea freight is standard for planned replacements; air freight is available for urgent situations.

SEIGO Machinery is an independent aftermarket manufacturer. All OEM part numbers, brand names and machine model designations are used for identification and cross-reference purposes only. These aftermarket components are not manufactured by, endorsed by, or affiliated with Komatsu Ltd.