日立EX1200‑5主液压泵 YA00003078 – 中国再制造

Why the EX1200‑5 Pump Is Different from Every Other Pump You Have Bought

You have replaced pumps on 20‑ton, 30‑ton, even 70‑ton machines. The EX1200‑5 is a different animal. Its main hydraulic pump (YA00003078) pushes over 1,200 L/min at pressures exceeding 34 MPa. It runs 20 hours a day, 6 days a week, in dust so thick you can taste it. When this pump fails, you do not call a service truck. You call a crane, a low‑boy, and a prayer.

Most hydraulic shops will not touch a pump this size. They lack the test stands, the tooling, and the experience. The few that do often cut corners – reusing bearings, skipping the critical step of grinding the cylinder block, painting over cracks. On a 120‑ton machine, those shortcuts cost you a week of production.

We remanufacture EX1200‑5 pumps properly, or we do not do it at all. Here is what proper actually means.

The Three Things That Kill EX1200‑5 Pumps – And How We Fix Each

1. Contaminated oil scoring the cylinder block and valve plate

On a smaller pump, a scored cylinder block might last another 1,000 hours. On an EX1200‑5, the massive flow rates turn micro‑scoring into catastrophic leakage within weeks. We do not clean and hope. We grind the cylinder block and valve plate to restore flatness to within 0.002mm. If grinding cannot save them, we replace them with new OEM‑grade components.

2. Bearing fatigue from millions of stress cycles

The bearings in an EX1200‑5 pump support loads that would crush a car. After 10,000 hours, every bearing has microscopic fatigue cracks. Some shops reuse them to save cost. We never do. All bearings are replaced – every single one. This is not negotiable.

3. Shaft seal failure from blocked case drain lines

On a 120‑ton excavator, the case drain line is long, routed through tight spaces, and easily kinked or plugged. A blocked drain creates back pressure that blows the shaft seal instantly on startup. We test every pump on a dyno with the case drain line open and monitored. We cannot fix a blocked line on your machine – but we can warn you before you install. We include a bold‑print installation sheet: “CHECK CASE DRAIN FIRST.”

What a Remanufactured YA00003078 Pump Actually Costs You

Let us skip the marketing and talk real numbers.

The used pump gamble: You pay $12,000 for a pump that looks clean. It fails after 800 hours. Now you pay again. And again. Suddenly you have spent more than a new OEM pump.

The HTD reman option: You pay once. You get a pump with new bearings, ground wear surfaces, and a test report. You install it. You run it for 3,000–5,000 hours. Then you decide whether to do it again.

Why You Cannot Just “Send It to Any Shop”

We have seen EX1200‑5 pumps that came from other “remanufacturers” with:

• Old bearings still installed – you could feel the roughness by hand

• Cylinder block scored but not ground – they just polished the surface

• Wrong torque on high‑pressure bolts – leading to oil leaks within days

• No test report – because they do not own a test stand capable of 1,200 L/min

A proper EX1200‑5 pump reman requires:

• A 200+ HP electric motor to drive the pump on the test stand

• Flow meters rated for over 1,000 L/min

• Pressure transducers accurate to 0.1 MPa

• A workshop that has done this before – not learning on your pump

We have the equipment. We have the experience. We have done EX1200 pumps for mines across Southeast Asia, Africa, and South America.

What You Will Receive

• YA00003078 pump, fully remanufactured – OEM规格，中国再制造

• Hydraulic test report – including rated pressure, flow, case drain, and control response

• All bearings new – no exceptions

• Cylinder block and valve plate re‑ground – flatness verified

• 全新密封件和 O 型圈 – high‑temperature fluororubber

• 发货前照片 – you see the actual pump before packing

• 重型木箱 – fumigation‑free, steel‑banded, built for sea freight

The Honest Warranty Statement

保修期根据产品详情为3至6个月。. 对于原装二手或再制造零件，我们不提供保修服务。. Here is why: We put our quality into the work before the pump leaves our shop. We do not rely on a warranty to fix problems after you install it. We rely on proper remanufacturing, rigorous testing, and your approval of pre‑shipment photos. For customers who need a traditional warranty, we can quote new aftermarket pumps – ask our sales team.

Before You Order – One Photo, One Serial Number

The EX1200‑5 had multiple production variants. The main pump mounting flange, drive spline, and regulator settings changed over the years. To confirm fitment, send us:

• 机器序列号 (EX1200‑5‑xxxxx)

• A clear photo of the old pump‘s nameplate (or the pump itself if the tag is missing)

We will reply within 24 hours with compatibility confirmation and a firm quote.

Installation note for EX1200‑5 pumps:
– The case drain line is your enemy if blocked. Before connecting the new pump, blow compressed air through the line to verify it is clear. A blocked drain will destroy the shaft seal instantly.
– Flush the hydraulic system and replace all filters. If the old pump failed with debris, the contamination is everywhere – valves, motors, cylinders. A new pump will not survive in a dirty system.
– Use new O‑rings and sealing washers on every port. Reused seals are the most common cause of external leaks.
– After installation, idle for 5 minutes, then slowly cycle each function to purge air. Do not overload the machine for the first hour.

Your EX1200‑5 is a production machine. Its main pump should not be the weak link. A properly remanufactured YA00003078 gets you back to digging – not next month, but now.