This complete repair kit is specially designed for JOST 50 series fifth wheel coupling (tractor saddle) on heavy-duty semi-trailers, tractors and commercial trucks. It contains all core worn locking and wearing spare parts required to overhaul the fifth wheel without replacing the entire coupling assembly.

1. Lock jaw / Lock hook: Cast steel main locking hook to secure the trailer kingpin
2. Wear plate (thrust pad): Anti-abrasive liner that bears friction between the kingpin and coupling
3. Wear ring / Half-moon friction ring: Curved wear-resistant gasket for the fifth wheel opening
4. Large return tension spring: Main reset spring for the lock jaw
5. Small auxiliary spring: Secondary spring for locking auxiliary reset
6. Cylindrical steel pins, hex bolts with thread locker, flat washers and cotter pin: Fasteners for assembly and positioning

1. Heavy-Duty Cast Steel Construction
   All load-bearing metal parts are made of high-strength alloy cast steel with black anti-rust spray coating, offering strong impact resistance and long service life under high tonnage transportation conditions.
2. Complete Matching Parts
   One kit covers all easily damaged wearable components of JOST 50 fifth wheel, eliminating the trouble of buying separate spare parts individually.
3. Perfect OEM Compatibility
   Precision casting with standard OEM part numbers marked on each component, fully interchangeable with original JOST 50 fifth wheel parts, fits mainstream heavy truck brands including Howo, Shaanxi Automobile, Dongfeng, FAW Jiefang and other domestic & imported tractors.
4. Cost-Effective Maintenance
   Instead of replacing the whole expensive fifth wheel saddle, this repair kit greatly cuts maintenance costs while restoring original locking safety performance.
5. Stable Locking & Safety Guarantee
   Tempered high-elastic springs maintain reliable locking tension to prevent accidental release of the trailer kingpin during highway transportation, complying with heavy vehicle safety standards.

• Semi-trailer tractors with JOST 50 type 2-inch kingpin fifth wheel coupling
• Long-distance logistics trucks, container transport vehicles, bulk cargo heavy haulers
• Repair shops, fleet maintenance stations, vehicle aftermarket spare parts supply

• Precisely machined dimensions for seamless installation without modification
• Anti-corrosion electroplating on springs and fasteners to resist mud, rain and road salt
• Wear-resistant alloy friction components reduce frequent replacement frequency
• Simple assembly operation, no special professional tools required for overhaul

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