عجلة مشط التبن لـ حفارة متوسطة الحجم Sumitomo SH120A1 SH120A2

SH120A1 SH120A2 Control Valve Assy for Excavator spare parts Hydraulic Main Valve

Product Overview

A compact excavator earns its keep on tight jobs — footings beside foundations, utility trenches along roads, site cleanup in spaces a 20‑ton machine cannot reach — and on the Sumitomo SH120A1 and SH120A2, the hydraulic main valve is what makes that work precise. It sits between the pumps and the cylinders, directing flow to boom, arm, bucket, swing and tracks. On a machine this size, control matters more than raw power: the operator needs to feather the bucket between pipes, hold a grade with the boom, and swing the house without disturbing the trench wall. That finesse lives inside the valve block.

When the valve wears on a worked SH120, the machine starts to feel clumsy. The boom drifts down while holding position, the bucket settles during an idle, the swing overshoots and hunts back, and the tracks surge when an attachment is cycled. Inside the block, worn spools and scored bores are letting oil bleed across the circuits. This aftermarket main valve replaces the whole assembly with fresh spools, springs and seals, set to the correct Sumitomo pressures for the A1 and A2 builds, so the old block comes off and the new one bolts straight back on.

Core Advantages

1. Fine control returns for tight‑spot work
Precision work needs clean metering. Lapped spools restore the feathering control that lets an operator hold a grade or position the bucket between pipes without the jumpy, grabby response of a worn valve.

2. The boom stays where it is put
Drift under a held load is oil escaping past worn spool lands. New spool‑and‑bore pairs hold position between lifts, cutting the constant re‑spotting that slows a small machine down.

3. Swing that respects the trench wall
Scored bores make the house sloppy — overshoot, then a hunt back. Fresh internals bring back smooth, controllable rotation, so the swing stops disturbing the edge of the work.

4. Tracks and attachments stop fighting
The valve sets flow priority between travel and working circuits. New internals restore the correct order, ending the surge when the bucket is cycled and the tracks grab.

5. A tested block instead of a fiddly rebuild
Re‑spooling a worn compact valve on the bench is delicate work with dozens of small parts. Swapping in this complete, bench‑tested assembly is one clean exchange with the same hose positions.

Manufacturing & Quality Control

Spool and bore pairs are finished to close clearance and run‑in on the bench to confirm free movement without stick‑slip. Each completed valve is flow‑tested across its circuits, with relief and compensator settings logged before acceptance; anything off spec is stripped and reworked. The finished block is oil‑fogged, port‑plugged and shipped on shock‑absorbing dunnage.

Frequently Asked Questions

Q1: Does this valve fit both the SH120A1 and SH120A2?
A: The platform is shared across the two builds, but port fittings can differ by year. Send the machine serial number and we confirm the correct block before dispatch.

Q2: What tells me the valve is the problem?
A: Drift under load, bucket settle at idle, sloppy swing with overshoot, and tracks that surge when attachments are cycled. A leak test on the valve will confirm before you buy.

Q3: Can I repair my existing valve instead?
A: Often yes — if the block casting is sound, a re‑spool and seal kit can restore it. Send photos and we will advise honestly on repair versus replacement cost.

Q4: What else should be changed at the same time?
A: The hydraulic oil and filters. Flush the circuit and change the return filter and suction strainer so the new spools run in clean oil from day one.

Q5: Is this interchangeable with the SH120‑5 or later models?
A: No — later SH120 generations use a different valve with updated porting and pressures. They are not interchangeable without major plumbing changes.

Q6: What is excluded from warranty?
A: Materials and build defects are covered. Damage from contaminated oil, water ingress, a seized spool forced into movement or incorrect pressure adjustment is not. Photograph any arrival damage before uncrating.