Hydraulic Seals Kit
Excavator & Machinery Cylinders
Hydraulic Seals Kit — Rod · Piston · Wiper · Buffer · Guide Rings
Complete hydraulic cylinder seal kits for excavators and construction machinery. We supply every seal position in the cylinder as a single matched set sized to your machine model, bore diameter and rod dimension. Compounds are selected per operating condition: PU and NBR for general-duty service, PTFE step-seals for low-friction high-cycle rods, FKM (Viton) for elevated temperature or aggressive hydraulic fluids. Three sourcing tiers available: genuine factory packaging, OEM-grade neutral packaging, and certified aftermarket from Tier-1 Chinese seal manufacturers.
| Rod Seal |
Piston Seal |
Wiper / Dust |
Buffer Ring |
Guide Ring |
O-Ring |
|
6
Seal Positions
|
4
Compounds
|
3
Quality Tiers
|
35+
Brands Covered
|
≤350 bar
Pressure Rating
|
ISO 7425
Groove Standard
|
Rod Seals — External Leakage Barrier
The rod seal is the most critical seal in any hydraulic cylinder. It retains pressurized fluid inside the cylinder bore while the reciprocating rod extends and retracts. On excavators working in abrasive dust and mud, the rod seal must also resist scoring from particles caught between the rod and seal lip. We stock three profiles across all common excavator bore sizes.
| Seal Profile / Type |
Compound |
Pressure |
Temp Range |
Typical Application |
PU U-Cup (Standard)
Single-lip polyurethane, loaded |
PU 94 Shore A |
Up to 250 bar
(3,600 psi) |
-35 to +100 C |
Boom, arm and bucket cylinders on XCMG XE215/XE370, SANY SY215/SY365, Komatsu PC200/PC300. General excavator duty cycle. |
PTFE Step Seal (Low-Friction)
PTFE face + NBR energizer O-ring |
PTFE + NBR 70 |
Up to 350 bar
(5,000 psi) |
-40 to +110 C |
High-cycle applications: travel motor cylinders, swing circuit cylinders, long-stroke attachment cylinders. Reduced breakaway force vs. PU. |
NBR Lip Seal (Economy)
Nitrile rubber single lip |
NBR 90 Shore A |
Up to 160 bar
(2,300 psi) |
-30 to +100 C |
Auxiliary cylinders: blade lift, dozer tilt, ripper, stabilizer legs on bulldozers (Shantui SD16/SD32), motor graders. |
Piston Seals — Chamber Separation
The piston seal sits in a groove machined into the piston head. Its job is to prevent internal bypass leakage between the head-end and rod-end pressure chambers. When this seal degrades you lose holding power, get drift under load, and the cylinder becomes inefficient even though no external leak is visible. Step-type piston seals are now the industry standard for excavator main cylinders because they combine near-zero static leakage with low friction.
| Seal Profile / Type |
Compound |
Pressure |
Temp Range |
Typical Application |
PTFE Step Seal
Rectangular PTFE ring + NBR O-ring energizer, ISO 7425-2 compliant groove |
PTFE + NBR 70 |
Up to 350 bar |
-40 to +110 C |
Main boom, arm and bucket pistons on all major excavator brands. Zero-leakage specification required by OEM rebuild standards. |
PU Piston Seal (Compact)
Loaded PU ring, fits narrow grooves where step seal won’t fit |
PU 95 Shore A |
Up to 250 bar |
-35 to +100 C |
Compact auxiliary cylinders, smaller-bore cylinders (under 50 mm), aftermarket replacement where original groove geometry is fixed. |
Wiper / Dust Seals — Contaminant Exclusion
The wiper seal is the first line of defense. Every particle of dust, mud, grit or metal swarf that gets past the wiper becomes an abrasive slurry that grinds down the rod seal from the outside in. On excavators working in quarry dust, demolition debris or coastal sand, wiper life often determines overall cylinder service interval. We offer two wiper constructions depending on your environment.
| Wiper Type |
Construction |
Max Speed |
Lip Material |
Best For |
Metal-Cased Wiper (Heavy-Duty)
Steel or stainless housing with bonded NBR/PU lip |
Steel + NBR 70 |
≤1.0 m/s |
NBR or PU |
Quarry, mining, demolition, rock-breaking attachments. Resists impact from large debris. Standard on CAT, Komatsu, Hitachi main booms. |
Snap-In Polyurethane Wiper
All-press-fit installation, no retaining ring needed |
PU 90 Shore A |
≤0.5 m/s |
PU monolithic |
General earthmoving, road building, material handling. Faster installation during field rebuilds. Used on XCMG XE series, SANY SY series auxiliary cylinders. |
Buffer Rings — Extrusion Protection
The buffer ring (also called a bumper ring or anti-extrusion ring) sits immediately behind the rod seal. Its function is not sealing but mechanical protection: when system pressure spikes (such as when a full bucket hits bedrock), the buffer ring closes the gap between the rod and gland to prevent the rod seal lip from extruding into that gap and being torn off. This is the single most common cause of sudden rod seal failure in excavator service. Every kit we supply includes correctly-sized buffer rings for each pressure zone.
| Buffer Ring Type |
Material |
Hardness |
Function |
Spiral Cut Buffer Ring
Continuous helical cut, easy install without special tools |
PU 95 Shore A |
95 Shore A |
Absorbs pressure spikes up to 350 bar. Prevents rod seal extrusion in high-shock applications (rock breaking, hammering, hard digging). Fits ISO 7425-1 grooves. |
Solid Buffer Ring (Closed)
Uninterrupted ring for maximum extrusion resistance |
PTFE-filled Bronze |
Rigid |
Maximum-pressure applications: hammer breaker circuits, shear and crusher attachments where pressure can exceed 400 bar intermittently. |
Guide Rings / Wear Rings — Metal-to-Metal Prevention
Guide rings (also called wear rings or bearing bands) sit in grooves on both the piston head and the cylinder gland (rod end). They prevent direct metal-to-metal contact between moving parts, centering the rod and piston within the bore. When guide rings wear thin, the rod starts to cock sideways under side-load, causing uneven loading on the rod seal and accelerated failure. Guide rings have no sealing function but they directly determine how long your rod seals will last under side-loading.
| Guide Ring Material |
Type |
PV Limit |
Wall Thickness |
Application |
Phenolic Fabric (Woven)
Cotton fabric impregnated phenolic resin |
Split ring |
0.8 MPa.m/s |
1.5 – 3.0 mm |
Piston guide on main boom and arm cylinders. High load capacity. Standard fitment on Komatsu PC200-8, CAT 320D, Volvo EC210 excavators. |
POM (Acetal)
Engineering thermoplastic, low friction coefficient |
Split or continuous |
0.5 MPa.m/s |
1.2 – 2.5 mm |
Gland (rod-end) guide ring. Lower friction than phenolic, good for long-stroke cylinders. Used on XCMG XE370, SANY SY365 large excavators. |
Filled PTFE
PTFE with bronze or glass fiber filler |
Split ring |
2.0 MPa.m/s |
1.0 – 2.0 mm |
High-speed, high-load specialty: long-front excavators, crane boom cylinders, telescopic handlers where PV limits are critical. |
O-Rings & Backup Rings — Static & Dynamic Sealing
O-rings serve multiple roles in every cylinder: as static seals on flanges, port bosses and cover plates; as dynamic energizers behind PTFE step seals; and as standalone light-duty rod/piston seals in low-pressure circuits. The compound choice determines temperature range, fluid compatibility and compression set performance. We stock AS568 standard sizes plus metric DIN 3771/JIS B2401 sizes used by Asian machinery OEMs.
| Compound |
Shore Hardness |
Temp Range |
Fluid Compatibility |
Common Use in Cylinders |
| NBR (Nitrile) |
70 Shore A |
-30 to +100 C |
Mineral oil, HLP hydraulic fluid, water-glycol |
Static flange/port seals, O-ring energizer in step seals, economy tier. The default choice for 80% of excavator cylinder positions. |
| FKM / Viton (Fluoroelastomer) |
75 Shore A |
-20 to +200 C |
Mineral oil, synthetic esters, some phosphate esters, fuels |
High-temperature environments: tropical climates, engines mounted close to cylinders, hot hydraulic systems. Also resists aggressive fluids in some bio-hydraulics. |
| PTFE Encapsulated |
Rigid shell |
-55 to +200 C |
Virtually all industrial fluids including strong chemicals |
Specialty: chemical injection pumps, marine cylinders exposed to salt spray, any application requiring near-zero compression set over years. |
Backup Rings (Anti-Extrusion): PTFE spiral-cut backup rings (also called “ring bearings” or “back-up washers”) are supplied with O-rings in high-pressure positions (above 150 bar). They fill the extrusion gap and allow softer compounds like NBR to be used at pressures that would otherwise require FKM.
Machine-Specific Repair Kits — OEM Reference Numbers
In addition to individual seals sold by size and profile, we supply complete machine-specific cylinder repair kits. Each kit contains every seal, O-ring, buffer ring and guide ring needed to overhaul one cylinder position (boom / arm / bucket / dozer blade). Kits are packaged by OEM reference number so you can cross-reference against your parts manual. Below are the most commonly requested kit families we stock or can source.
| Brand / Series |
Kit Reference No. (Example) |
Fits Machine Models |
Cylinder Position(s) |
XCMG (Xuzhou)
XE Series Excavators |
860129944 (Repair Kit) |
XE60, XE75, XE80, XE135, XE150 |
Boom / Arm / Bucket cylinder sets |
| 860160813 (Repair Kit) |
XE215C, XE235, XE260C, XE370, XE380C |
Main hydraulic cylinders + swing circuit |
|
803195188 (Shaft Seal 85x100x9) |
XE215C |
Specific shaft seal — cross-reference by size |
SANY (Sany Heavy Industry)
SY Series Excavators |
A260409000416 (Seal Kit, 0.25 kg) |
SY215, SY235 (matching models) |
Bucket cylinder assembly |
| 60107382K (Cylinder Boom Kit) |
SY215-8, SY235, SY265, SY305 |
Boom cylinder complete seal set |
Komatsu
PC Series Excavators |
707-99-46120 / 46130 / 57160
(Hydraulic Cylinder Seal Kit family) |
PC200-7, PC200-8, PC220-8,
PC270, PC290, PC300-8 |
Boom / Arm / Bucket cylinder seal kits.
Rubber compound, ISO9001 certified. |
Multi-Brand Universal
Aftermarket Equivalent |
860129953 / 860129954 / 860129952
(Excavator Seal Kit Set) |
XCMG, Liugong, Lovol, SDLG
(cross-compatible models) |
Universal cylinder repair kit set.
OEM-equivalent quality, neutral packaging option. |
| Custom Kit (by drawing or sample) |
Any brand, any model |
Send us your old seal set, a photo, or the groove dimensions. We match profile, compound and tolerance within 5–7 business days. |
Three Quality Tiers — Choose What Fits Your Market
Tier 1 — Genuine OEM (Branded Packaging)
Factory-original seal kits in branded packaging with OEM part numbers and inspection certificates. Produced by the same seal manufacturer that supplies the machinery OEM’s production line. Includes traceability documentation (batch code, date code, material certificate). Best for dealers serving end-users who insist on genuine parts and are willing to pay the premium. Lead time: 10–20 days from order confirmation.
Tier 2 — OEM-Grade Replacement (Neutral Packaging)
Manufactured by Tier-1 Chinese seal factories (many of whom are actual OEM suppliers) using the same compound formulations, tooling and QC standards as genuine parts. Supplied in plain neutral packaging with Archer quality label. Dimensionally interchangeable with OEM references — same groove fit, same hardness, same pressure rating. This is the tier most volume importers choose. Lead time: 5–12 days. MOQ: typically 1 kit (no forced bundle).
Tier 3 — Certified Aftermarket (Budget)
Economy-tier seals from audited domestic manufacturers meeting ISO 9001 baseline. Suitable for older machines (10+ years), rental fleet maintenance, or markets highly sensitive to price. Compound and dimensional tolerance are within acceptable range but not at the premium level of Tiers 1 and 2. We clearly label these as aftermarket so there is no ambiguity for your customer. Lead time: 3–7 days. MOQ: flexible from single pieces up.
Why Source Hydraulic Seal Kits From Archer?
| Capability |
What It Means for You |
| Machine Model + Serial Cross-Reference |
Give us the machine model and serial number (or VIN / chassis number). We identify the correct seal kit reference, confirm groove revision differences between production years, and flag any superseded part numbers before you order. |
| Compound Selection Guidance |
Not sure whether to use PU, NBR, PTFE or FKM for a given position? Tell us the operating temperature, fluid type, duty cycle and contamination level. We recommend the right compound and explain why — so you don’t pay for FKM where NBR suffices, or risk premature failure by underspecifying. |
| Mixed-Tier Ordering |
Order genuine rod seals (Tier 1) for the most critical positions and OEM-grade wipers/guide rings (Tier 2) for the rest — all in one shipment, one invoice. You control cost-per-position without managing multiple suppliers. |
| Batch Inspection Before Shipment |
Every seal kit order is visually inspected and dimension-sampled before packing. Hardness (Shore durometer) is spot-checked on random samples from each batch. Photos of the packed kit can be sent for your approval before dispatch. |
| Custom Kit Development |
Have an obsolete machine or a non-standard custom cylinder? Send us the old seals (even worn ones), a drawing, or the groove measurements. We work with our seal manufacturing partners to reverse-engineer and produce a matching kit — typically within 5–7 business days for common sizes. |
Frequently Asked Questions
Q1.How do I specify the correct seal kit for my machine?
Provide the machine brand, model and serial number (e.g., “XCMG XE215C SN: XE21Cxxxx”). If you know which cylinder needs rebuilding (boom / arm / bucket / blade), include that too. If you only have the old seals, send photos showing any visible part numbers stamped on them, or measure the bore diameter, rod diameter and groove dimensions with calipers. We cross-reference everything against our database of OEM seal kit references before quoting.
Q2.Which compound should I choose for my operating conditions?
For most excavators in temperate climates running mineral-oil hydraulics, PU (94–95 Shore A) for rod/piston seals and NBR (70 Shore A) for O-rings/wipers is the proven default — it covers 85% of applications. Upgrade to PTFE step seals if the cylinder operates above 250 bar or cycles faster than 30 strokes/minute. Choose FKM (Viton) if ambient temperatures regularly exceed 50 C or if your hydraulic fluid runs hotter than 85 C. If you are unsure, describe your conditions and we will specify the appropriate compound for each position in the kit.
Q3.What is the lead time for seal kit orders?
Stock bore sizes in PU/NBR (the most common combinations) ship within 3–5 business days from China. OEM-branded kits (Tier 1) require 10–20 days depending on brand availability. Custom-manufactured kits (non-standard sizes or obsolete machines) run 5–10 business days. FKM compounds and PTFE-filled guide rings add 2–4 days to any tier. Exact lead time is confirmed on the quote before you commit, and we notify you immediately if a delay occurs.
Q4.Can I order individual seal types instead of a complete kit?
Yes. Many customers keep a full rebuild kit in stock and reorder individual seal types (typically rod seals and wipers, which wear fastest) as preventive spares. We track your previous orders by machine model so that reorders maintain consistent compound and sizing — just tell us “same as last order for XCMG XE215C boom cylinder” and we pull your file.
Q5.Do you supply seal kits for machines other than excavators?
Yes. Our seal catalog covers wheel loaders (SDLG, XCMG LW series, CAT 9xx, Volvo L-series), bulldozers (Shantui SD16/SD22/SD32, Komatsu D-series), motor graders, cranes (XCMG QY series, SANY STC series), heavy trucks (HOWO, SHACMAN, Beiben steering and brake cylinders), and industrial hydraulic presses. Provide the machine details and we check availability.
Q6.What shipping and payment terms do you offer?
Shipping: EXW, FOB Qingdao/Shanghai/Ningbo, CIF/CNF to your nearest sea port, or air freight for urgent small orders. Payment: 30% deposit via T/T or wire, 70% balance against copy of BL and inspection photos before release. Sample orders can be paid 100% upfront. PayPal/Western Union accepted for trial orders under USD 2,000.
Need Hydraulic Seal Kits? Get a Quote Today
Send your machine model, serial number or cylinder dimensions. We will confirm fitment, select the right compound tier, and return a detailed quotation within 24 hours.
