178-27-21850

The 178-27-21850 is a Komatsu OEM-replacement track bolt manufactured by AzuLong Wear Parts. This Grade 12.9 hex head fastener is produced from 35CrMo Alloy Steel with black oxide finish, designed for undercarriage track shoe fastening for large komatsu bulldozers. The metric fine-thread specification ensures precise torque control during installation — critical for maintaining proper track tension and shoe alignment.

Grade 12.9 — Strength & Reliability

Grade 12.9 track bolts represent the highest strength class commonly used in undercarriage applications, with tensile strength reaching 1220 MPa. Manufactured from 35CrMo or 42CrMo alloy steel, these bolts are specified for heavy-duty tracked equipment operating in demanding conditions — mining sites, quarries, and construction in rocky terrain where track shoe bolts are subjected to extreme impact and vibration loads.

Undercarriage Engineering

Track bolts are among the most safety-critical fasteners on any tracked machine. They secure the track shoes to the chain links, and bolt failure during operation can cause the track to derail — creating a dangerous situation and costly downtime. The hex head design allows high-torque installation with standard tools, while the thicker head profile (compared to standard hex bolts) provides additional shear resistance at the bolt-head/shoe interface. Each AzuLong track bolt undergoes controlled heat treatment to achieve uniform hardness and is inspected for thread accuracy, head concentricity, and surface finish before shipping.

Equipment Compatibility

Compatible with Komatsu bulldozers and large tracked equipment used in mining and large-scale earthmoving operations. Specific equipment: Komatsu D85, Komatsu D155, Komatsu D275, Komatsu D375. Always follow the equipment manufacturer's torque specifications when installing track bolts. Under-torqued bolts can work loose from vibration; over-torqued bolts risk fatigue cracking. Contact rocky@azulong.com or WhatsApp +86-13777046128 for pricing, availability, and torque specifications.

• Komatsu D85
• Komatsu D155
• Komatsu D275
• Komatsu D375