
We specialize in aftermarket seal kits compatible with brands such as Caterpillar, Komatsu, JCB, and John Deere. We offer B2B bulk order consultation and large-scale procurement services. With years of industry experience, we provide wholesale and long-term bulk supply services to our global business partners. Submit your bulk order details, and our professional B2B team will provide you with competitive pricing, fast delivery times, and customized supply solutions within 24 hours.
6669591 is an aftermarket swivel joint crown seal supplied by Ruijueparts. The original crown-seal reference describes a crown element with an O-ring. It is a different service item from the swivel oil seal identified as 6669586. Match the original service number, machine serial number and installed assembly before ordering. Custom sealing enquiries for older equipment can be assessed from dimensions and assembly details. Send the assembly identification for a more precise fit check.
Part Number: 6669591
Compatible Brand: Bobcat
Type: Swivel Joint Crown Seal
Manufacturer Type: Aftermarket
Condition: New
Compact Excavator: Bobcat 341, subject to serial number and installed swivel assembly.
Function: Seals the specified crown position while the hydraulic swivel accommodates upper-structure rotation.
Fit check: Verify the machine serial number and installed assembly in the parts catalogue.
Do not substitute by appearance. The original catalogue assigns different references to the crown seal and oil seal; match the required service position.
The original product page reviewed lists 341. Send the 337 serial number and swivel reference for a separate check before ordering for that model.
Custom sealing enquiries are available for older equipment. Send the assembly reference, dimensions and photos so feasibility can be assessed before a supply commitment.
Image note: General seal illustration only; the image does not specify supplied quantity, dimensions or materials.
Aftermarket replacement supplied by Ruijueparts. Bobcat names and part numbers identify reference applications; this is not a genuine Bobcat product.
Our aftermarket seal kits deliver a practical, cost-effective solution without compromising on real-world performance. We offer a lower upfront cost and reliable sealing for your daily maintenance and repair needs.
We stock seal kits across CAT, Komatsu, Volvo, JCB, Hitachi, Doosan, John Deere, Kubota, and 10+ other brands—one supplier for your whole fleet.
Ship under RuijueParts branding, neutral (unbranded) packaging, or your own private label. Suitable for resellers and distributors.
When genuine OEM seals are out of production for your old machinery, we can custom-make oil seals using your dimensions or our engineer-recommended specifications.
Ship under RuijueParts branding, neutral (unbranded) packaging, or your own private label. Suitable for resellers and distributors.
Volume pricing for repair shops, dealers, and fleet operators. Get a quote via our website or WhatsApp: +86 13692100161.
OEM seal kits are the right choice when machinery is under active warranty, operating at peak duty cycles, or when failure risk is unacceptably high. Budget aftermarket—like Ruijue Parts—makes sense in these common scenarios:
When a machine is aging out of your fleet, OEM parts cost more than the job warrants. A budget kit extends service life without over-investing.
For machines used infrequently or on lower-intensity tasks, premium OEM pricing may not be justified.
When OEM stock is out or delivery takes weeks, an available aftermarket kit gets your machine running now.
Repair shops and fleet managers running high volumes of machines often balance OEM and aftermarket across their portfolio based on criticality.
Fully retract the cylinder and relieve system pressure before disassembly. Never work on a pressurized circuit.
Remove from the machine. Unthread the gland nut and withdraw the piston rod carefully to avoid surface damage.
Clean the bore, rod, and all metal parts with a lint-free cloth. Contamination introduced during reassembly accelerates seal wear—this step is especially important for budget-grade seals.
Check for scoring or pitting. Budget seals are more sensitive to surface imperfections—address rod damage before fitting new seals.
Lightly coat each seal with clean hydraulic fluid before installation. Use proper seal drivers — not screwdrivers or sharp tools — to avoid nicking the sealing lip.
Torque the gland nut to spec and cycle the hydraulic system under no-load conditions. Inspect for leaks before returning the machine to service.
Budget-grade seals may have shorter service intervals than OEM. Inspect rod seals for moisture, oil film, or weeping more frequently and replace proactively.
Contaminated fluid degrades seals faster — this applies especially to non-OEM materials. Replace fluid and filters on schedule.
When storing equipment with cylinders extended, protect rod surfaces from corrosion and debris to preserve wiper seal life.
Avoid using sharp tools during assembly to prevent nicks or scores on the seal lips. Pre-lubricating all components with clean hydraulic oil is recommended to ensure a smooth fit into the cylinder grooves.
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