CAT 535-6284 Bushing (SEM)

CAT 535-6284 is a Caterpillar genuine SEM (steel-based sintered bronze composite bushing for steering/suspension/travel mechanisms), compatible with Cat 140M/160M grader steering knuckle kingpins and 938G loader suspension rocker arm axle pins. Its core function is to provide self-lubricating wear-resistant protection under low-speed, heavy-load conditions, reducing wear on the shaft and bore mating surfaces. The following are professional technical and application information:

Core Technical Parameters (Professional Version)

Item Details
Basic Attributes
Model 535-6284, Type SEM steel-based sintered bronze composite bushing (steel back + bronze sintered layer + PTFE self-lubricating film), compatible with Cat 140M/160M grader steering knuckle kingpins and 938G loader suspension rocker arm axle pins, steel back material Q345B alloy steel (thickness 4 mm, HRC 28-32), bronze layer material CuSn10Pb10 (thickness…) 1.5 mm (HB 90-110), PTFE film thickness 0.08 mm (including MoS₂ wear-resistant filler), inner diameter φ65 mm, outer diameter φ75 mm, total length 85 mm, single weight approximately 0.82 kg, rated static load ≥800 kN, rated dynamic load ≥450 kN, operating temperature -50℃ to +120℃, coefficient of friction ≤0.05 (initial value without lubrication)

Key dimensions: inner diameter tolerance +0.015/-0.010 mm, outer diameter tolerance 0/-0.020 mm, length tolerance ±0.12 mm, chamfers at both ends 1.5×45°, steel back cylindricity ≤0.01 mm, bronze layer porosity 15%-20% (oil storage lubrication), PTFE film complete coverage without pinholes, compatible shaft diameter φ65 mm (tolerance f7), mounting hole diameter φ75 mm (tolerance f7) H7)
Material and Manufacturing Process: The steel backing undergoes quenching and tempering treatment; the bronze layer is vacuum sintered and rolled; the PTFE film is electrostatically sprayed and thermosetting; the inner wall of the bushing has φ0.8 mm oil reservoir holes (12 mm spacing, ring array) for long-term grease storage, suitable for low-speed heavy-load conditions without forced lubrication.

Compatible Models: Cat 140M/160M grader (serial number JDH1500-UP) steering knuckle kingpin; 938G loader (serial number KAT900-UP) suspension rocker arm pin. The core is used for the shaft-hole fit of the steering/suspension mechanism, bearing radial heavy loads and small swing loads, suitable for operating conditions with speeds ≤50 r/min and impact loads ≤12 kN.

Assembly and Fit: The bushing has an interference fit with the hole (interference 0.018-0.025 mm) and a clearance fit with the shaft (clearance 0.03-0.05 mm). (mm), rear end face runout ≤0.03 mm, radial runout ≤0.02 mm. Install using liquid nitrogen cooling and a dedicated press tool. Do not strike the steel back.

Installation and Maintenance Points:

Before installation, clean the journal, mounting hole, and bushing surfaces, checking for burrs/rust. No additional grease is needed (the PTFE film provides initial self-lubrication; the oil reservoir can be pre-filled with Cat 2V lithium-based grease).

During assembly, first cool the bushing with liquid nitrogen (-196℃, 10-15 minutes), then use a dedicated press tool to press it into the mounting hole at a uniform speed. After pressing, check for bushing deformation, undamaged PTFE film, and axial movement ≤0.1 mm after pin installation.

Maintenance recommendations: Check the bushing clearance every 1200 hours. Replace immediately if the inner diameter wear is >0.15 mm or the PTFE membrane falls off. Replenish with grease every 500 hours through the grease fitting (approximately 0.1 kg each time) to prevent dry friction from causing bushing erosion.