CAT 9R2821 BOSS for 365B Caterpillar Part - WSTPARTS
The 9R2821 BOSS is a genuine and high-quality OEM replacement part compatible with Caterpillar 365B and 330C equipment. It is categorized under Structure. Every unit is fitment-verified before dispatch. Manual reference: 330C: FRAME AND BODY, group 201-2783, page 404; 345B: IMPLEMENTS, group 167-9846, page 787.
9R2821 BOSS for Caterpillar 365B — Genuine & OEM Replacement Part
WSTPARTS supplies genuine and high-quality OEM replacement BOSS (Part # 9R2821). Designed for CAT 365B, 330C, 345B, 345C, 345D equipment.
Compatible Models
Key Features
- ✔ 100% compatible with CAT 365B, 330C, 345B, 345C, 345D
- ✔ Meets Caterpillar original quality and performance standards
- ✔ Genuine CAT parts with anti-counterfeit label | OEM alternatives with warranty
- ✔ Available for order, contact for lead time
Specifications
| Part Number (MPN) | 9R2821 |
| Product Name | BOSS |
| Brand | CAT |
| Applicable Models | 365B, 330C, 345B, 345C, 345D |
| Weight | 0.05 kg |
| Condition | New (Genuine / OEM Equivalent) |
| Warranty | 12 Months |
Where This Part Fits
Every row below is a real listing of 9R2821 in the Caterpillar parts manual: the machine it is published under, the system it belongs to, the group number and the manual page. Use it to confirm the part against your own parts book before ordering.
| Machine | System | Group No. | Manual Page |
| 330C | FRAME AND BODY | 201-2783 | p.404 |
| 345B | IMPLEMENTS | 167-9846 | p.787 |
| 345C | IMPLEMENTS | 228-5427 | p.820 |
| 365B | IMPLEMENTS | 208-1921 | p.656 |
| C9 | AIR INLET AND EXHAUST SYSTEM | 242-3118 | p.160 |
| 330C | FRAME AND BODY | 231-6966 | p.405 |
| 345B | IMPLEMENTS | 167-9851 | p.789 |
| 345C | IMPLEMENTS | 228-5432 | p.821 |
System Notes — FRAME AND BODY
The frame and body group covers the main frame, counterweight, fenders, steps, handrails, access doors, panels and the mounting hardware that ties them together. It carries every load the machine generates and every load the attachment imposes back into the structure. Cracks almost always start at a weld toe or a bolt hole where a mounting has worked loose, and a loose guard or step is both a structural and a safety issue. Parts in this group are replaced after impact damage, after crack repair, or when fasteners no longer hold torque because the hole has elongated.
System Notes — IMPLEMENTS
The implements group covers the working attachment and its linkage: bucket or blade, cutting edges, teeth and adapters, pins and bushings, linkage arms, tilt cylinders and the wear plates that protect them. This is the group that actually does the work, so it wears fastest. Cutting edges round off, teeth break at the adapter, and pins and bushings develop play that spreads shock loads back into the linkage. Parts here are replaced on measured wear — pin and bushing clearance, edge thickness, tooth height — rather than on hours, because a worn edge costs fuel and cycle time long before it fails outright.
FAQ
Is 9R2821 the right part for my machine?
Match the part number on your old part, or send us your equipment serial number — WSTPARTS verifies fitment free of charge for CAT 365B.
Genuine vs OEM replacement — what is the difference?
Genuine CAT parts carry an anti-counterfeit label. OEM equivalents are built to the same specifications, bench-tested and supplied with full warranty at a better price.
Stock, shipping and warranty?
Lead time confirmed on request; we quote the fastest available option. Every order is covered by a 12-month warranty.
📞 Get a Quote: Contact the WSTPARTS parts team | Email: cat@wstparts.com
