CAT 8C3121 BOLT for C18 Caterpillar Part - WSTPARTS
Need a dependable Bolt/Nut part for your Caterpillar C18, 3516B and 3512 machine? The 8C3121 BOLT from WSTPARTS is manufactured to OEM-grade tolerances. It is categorized under Bolt/Nut. Every unit is fitment-verified before dispatch. Manual reference: 3412C: ELECTRICAL AND STARTING SYSTEM, group 151-7689, page 551; 3512: FUEL SYSTEM, group 124-3174, page 824.
8C3121 BOLT for Caterpillar C18 — Genuine & OEM Replacement Part
WSTPARTS supplies genuine and high-quality OEM replacement BOLT (Part # 8C3121). Designed for CAT C18, 3516B, 3512, 3412C equipment.
Compatible Models
Key Features
- ✔ 100% compatible with CAT C18, 3516B, 3512, 3412C
- ✔ 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) | 8C3121 |
| Product Name | BOLT |
| Brand | CAT |
| Applicable Models | C18, 3516B, 3512, 3412C |
| Weight | 0.05 kg |
| Condition | New (Genuine / OEM Equivalent) |
| Warranty | 12 Months |
Where This Part Fits
Every row below is a real listing of 8C3121 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 |
| 3412C | ELECTRICAL AND STARTING SYSTEM | 151-7689 | p.551 |
| 3512 | FUEL SYSTEM | 124-3174 | p.824 |
| 3516B | COOLING SYSTEM | 263-8044 | p.265 |
| C18 | AIR INLET AND EXHAUST SYSTEM | 201-1270 | p.511 |
| 3516C | ELECTRICAL AND STARTING SYSTEM | 166-4373 | p.414 |
| 3412C | ELECTRICAL AND STARTING SYSTEM | 166-0887 | p.553 |
| 3412C | ELECTRICAL AND STARTING SYSTEM | 166-0889 | p.555 |
| 3516B | ELECTRICAL AND STARTING SYSTEM | 166-4373 | p.644 |
System Notes — ELECTRICAL AND STARTING SYSTEM
The electrical and starting system covers the battery, starter motor, alternator, wiring harness, relays, switches and the instrument panel. It carries current from the batteries to the starter to crank the engine, and from the alternator back to keep the batteries charged. Because these machines work in dust, vibration and wide temperature swings, connectors corrode, harness insulation chafes against the frame, and starter solenoids burn out from repeated short cranks. Parts in this group are usually replaced on a symptom basis — slow cranking, a dash warning, lights that dim under load, or a no-start condition traced to an open circuit.
System Notes — FUEL SYSTEM
The fuel system covers the injection pump, injectors, fuel transfer pump, filters and water separator, lines and the tank. It meters and atomises diesel at the precise moment and quantity the engine needs. Modern CAT engines run very tight injector tolerances, so the group is sensitive to water and dirt: a worn injector dribbles instead of atomising, causing rough idle, white smoke and diluted oil, while a clogged filter starves the pump under load. Parts here are replaced when the engine misfires, smokes, loses power under load, or when the water separator keeps tripping — always after the fuel quality itself has been ruled out.
FAQ
Is 8C3121 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 C18.
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
