The Hyundai R220LC-9S Hydraulic Cylinder Seal Kit uses separate hydraulic cylinders for the boom, arm and bucket. Although these cylinders perform similar hydraulic functions, their bore sizes, rod diameters, seal profiles and seal kit part numbers are normally different.

Ordering a seal kit based only on the excavator model can therefore result in the wrong parts. To identify the correct kit, you should confirm the cylinder position, machine serial number and, whenever possible, the cylinder assembly part number.

Find the correct R220LC-9S Hydraulic Cylinder Seal Kit for boom, arm and bucket cylinders. Faseals can help you identify the right kit and avoid fitment mistakes.

1、Hyundai R220LC-9S Hydraulic Cylinders

Boom Cylinder：raises and lowers the boom

Arm Cylinder：（ Stick Cylinder 、Dipper Cylinder）Controls arm/stick movement

Bucket Cylinder:Opens and closes the bucket

2、Hyundai R220LC-9S Boom vs Arm vs Bucket hydraulic Cylinder Seal Kit

Item	Boom	Arm	Bucket
Cylinder position	Boom	Stick / Arm	Bucket
Typical quantity	2	1	1
Rod diameter	Model-specific	Different	Different
Bore diameter	Model-specific	Different	Different
Seal kit	Unique	Unique	Unique
Interchangeable?	Normally No	Normally No	Normally No

Even though all three cylinders are installed on the same R220LC-9S excavator, the seal kits should not be assumed to be interchangeable.

3、What Is Included in R220LC-9S Hydraulic Cylinder Seal Kit?

• Piston Seal：Prevent hydraulic oil from leaking into the piston from both sides.
• Rod Seal：To prevent hydraulic oil from leaking outwards from the piston rod end.
• Buffer Seal：It withstands instantaneous pressure peaks and protects the rod seal.
• Dust Seal：Prevent mud, dust, and water from entering the oil cylinder.
• O-Rings
• Backup Rings
• Wear Rings：Keep the piston/rod seal centered to reduce metal contact.
• Static Seals

4、How to Identify the Correct R220LC-9S hydraulic Cylinder Seal Kit

Method 1：Confirm cylinder position

Boom / Arm / Bucket

Method 2：Provide part number

For example：

Machine Model: Hyundai R220LC-9S  ARM SEAL KIT
Part Number: 31Y1-15230

Method 3：Provide machine nameplate

Method 4: If the nameplate and part number are missing, you can measure the dimensions of the seal kit

·  Inner diameter

·  Outer diameter

·  Height

Measurements are useful as a secondary verification method, but cylinder part numbers should be used whenever available.

5、When is it necessary to replace the hydraulic cylinder seal kit?

1.Rod-end oil leakage

Common causes:

• Rod seal damaged
• Buffer seal failure
• Contaminated sealing surface

2. Boom or arm slowly drops

Common causes:Piston seal internal leakage

Cylinder drift can also be caused by control valve leakage.

3.Weak cylinder force

The reduced digging force may indicate an internal leak.

4. Dust or oil around wiper seal

If the Wiper is damaged, contaminants will enter the oil cylinder.

6、When Replacing Seals Alone Is Not Enough

If the following situations occur, simply replacing the Seal Kit may cause oil leakage again.

• Piston rod scratched
• Rod chrome peeling
• Bent rod
• Cylinder bore scoring
• Damaged gland
• Excessive bushing play
• Metal contamination
• Damaged seal groove

A new seal kit cannot compensate for a damaged rod, worn cylinder bore or excessive mechanical play.

7、Seal Materials Used in Excavator Cylinders

• PU / Polyurethane
• NBR
• PTFE
• FKM

8、Common Installation Mistakes

• ·  Seal installed backwards
• ·  Scratching seal during assembly
• ·  No lubrication
• ·  Dirty cylinder parts
• ·  Reusing damaged wear rings
• ·  Mixing seals from different kits
• ·  Installing wrong-size backup rings
• ·  Not checking rod surface

Never use a sharp screwdriver directly on the sealing lip.

9、What Information Should You Send Before Ordering?

• Seal kit part number
• Machine model
• Cylinder Position：boom,arm,bucket
• Quantity

FAQ：

Are the boom and arm cylinder seal kits the same on a Hyundai R220LC-9S?

No. They normally use different seal dimensions and kit part numbers.

How many boom cylinder seal kits does an R220LC-9S need?

The machine normally has two boom cylinders, so repairing both usually requires two seal kits.

Can I order using only the machine model?

It is better to provide the serial number and cylinder part number.

What seals are included in a cylinder repair kit?

Typically piston seals, rod seals, wipers, O-rings, backup rings and wear rings, depending on the kit.

Why is my hydraulic cylinder still leaking after installing new seals?

Possible causes include a damaged rod, worn bore, incorrect installation, contamination or the wrong seal size.

How can I identify my Hyundai cylinder part number?

Check the cylinder body, machine parts catalog or provide the machine serial number to your supplier.

Need help identifying the correct Hyundai R220LC-9S hydraulic cylinder seal kit?

Send your machine model, cylinder position, and cylinder part number to Faseals for verification. Photos of the machine nameplate and cylinder are also helpful in confirming the correct seal kit.