CAT 077-9536 Bearing-Aligning

CAT 077-9536 is a wear-resistant sealing bushing for Caterpillar hydraulic cylinders/drive shafts. It is used for sealing and guiding, and is suitable for sealing the piston rod or bearing housing of cylinders in equipment such as 336D2/349D excavators and 980M loaders. It is often used in conjunction with O-rings and dust seals to prevent hydraulic oil leakage and contaminant intrusion, ensuring the long-term reliability of the sealing system. The following is structured technical and application information:

Core Technical Parameters
Item Details
Basic Attributes
Model 077-9536, Sealing Bushing (Wear-resistant Guide Bushing), material is filled polytetrafluoroethylene (PTFE + bronze powder, hardness HB60-70, friction coefficient 0.05-0.08, self-lubricating), working temperature -50℃ to +150℃, single weight approximately 0.2 kg, suitable for hydraulic cylinder/drive shaft sealing and guiding, leak-proof, pollution-proof, suitable for medium and low pressure (≤35 MPa), reciprocating/low speed rotation conditions

Key Dimensions
Inner diameter 60 mm (tolerance 0/-0.012 mm), outer diameter 75 mm (tolerance +0.012/0 mm), total length 30 mm, wall thickness 7.5 mm, inner hole surface roughness Ra≤0.2 μm, mating tolerance inner ring h6 (0/-0.012 mm), outer ring H7 (+0.025/0 mm) 15° chamfer × 1 mm, coaxiality ≤ 0.015 mm. Compatible models: Cat 336D2/349D excavators (boom cylinder piston rod sealing guide part), 980M loader (bucket cylinder cylinder end sealing bushing), D8T bulldozer (bucket cylinder dustproof sealing guide sleeve). Matching O-rings (077-9537) and dust rings (449-4753) use Cat® Parts. Assembly fit: Inner bore and piston rod transition fit (clearance 0.003-0.010 mm), outer ring and cylinder/bearing housing interference fit (interference 0.005-0.010 mm). Compatible with 60 mm diameter piston rods. Piston rod surface must be chrome plated (thickness 0.05-0.1 mm) and polished (Ra≤0.1 μm). Cylinder bore must be precision bored (Ra≤1.6). (μm) Installation and Maintenance Points: Before installation, clean the inner and outer surfaces of the bushing, piston rod, and mounting holes. Check for scratches, deformation, and impurities. Measure dimensions to ensure the fit is correct. The chamfered surface of the bushing should face the outside of the sealing cavity to avoid scratching the sealing ring.

Use a dedicated installation sleeve for cold pressing. Do not strike the end face to prevent damage to the PTFE layer. After installation, check for axial movement ≤0.03 mm to ensure no jamming and good sealing surface contact.

Lubrication and Maintenance: Before assembly, apply hydraulic oil (same type as the system), filling to 10-15% of the bushing-piston rod clearance. Check for wear every 800 hours. If the inner bore wear exceeds 0.1 mm or grooves appear, replace immediately. It is recommended to replace at the same time as the O-ring and dust ring.