CAT 385-3613 20.8mm Thick Spacer

CAT 385-3613 is a Caterpillar original flat seal gasket (used for sealing the mating surfaces of hydraulic pumps, gearbox housings, or flange faces). It is compatible with the high-pressure hydraulic circuits and drivetrain mating surfaces of Cat® excavators and loaders. The following is pure original data and does not include replacement parts information (Cat® Parts).

Core Technical Parameters (Raw Data)

Item Details
Basic Attributes
Model 385-3613, Type: Asbestos-free composite fiber flat gasket (compliant with SAE J200 standard), Material: NBR rubber coated with aramid fiber reinforcement layer (double-sided coating with high-temperature resistant sealant, asbestos-free environmentally friendly formula), Single weight: 0.085 kg, Applicable working conditions: high-pressure static sealing (hydraulic oil/gear oil medium), Working temperature: -40℃ to +180℃, Sealing pressure: ≤35 MPa, Protection level: IP67, Compatible flange roughness: Ra 3.2-6.3 μm

Key Dimensions
Outer diameter: D=125 mm (tolerance 0/+0.30 mm), Inner diameter: d=85 mm (tolerance 0/-0.25 mm), Thickness: t=3.0 mm (tolerance ±0.10 mm), Number of bolt holes: 6, Bolt hole diameter: φ12 mm (tolerance +0.10/-0.05 mm), Bolt hole distribution circle diameter: PCD=105 mm (tolerance ±0.15 mm), edge chamfer C0.3 (tolerance ±0.1 mm)

Performance Parameters: Compression ratio 15%-20% (loaded at 30 MPa), rebound rate ≥25% (after unloading), leakage rate ≤0.01 cm³/min (35 MPa oil pressure), oil resistance (IRM 903 oil, 100℃×72h): volume change rate ≤5%, aging resistance (150℃×1000h): tensile strength retention ≥80%, shear strength τ=8.5 MPa, peel strength ≥1.2 N/mm

Structural and Performance Advantages: Composite sealing structure: NBR rubber + aramid fiber reinforcement layer provides high elasticity and tear resistance; double-sided sealant can fill minor scratches on the joint surface, adapting to the dynamic sealing requirements under vibration conditions in engineering machinery.

Asbestos-free environmentally friendly formula: Complies with EU RoHS standards, avoiding the hazards of asbestos dust, meeting stringent environmental requirements, and resistant to various engineering machinery media such as hydraulic oil and gear oil.

High-precision dimensional control: Strict dimensional tolerances, compatible with CAT original flange bolt hole positions and mating surface precision, ensuring a sealing surface fit of ≥98% after installation, eliminating the risk of leakage.

Lightweight and efficient sealing: Weighing only 85g, it has minimal impact on equipment weight, requires no additional sealant during installation, allows for quick replacement, and improves maintenance efficiency.

Installation and maintenance points (raw data)

Installation: Clean the mating surfaces (free of oil, burrs, and carbon deposits). The gasket has no front or back distinction; place it centered on the flange face. Tighten the bolts in a crisscross sequence in 3 steps (pre-tightening force 25 N·m → 50 N·m → final 80 N·m). After installation, hold the pressure for 30 minutes; no leakage indicates acceptance.

Maintenance: Inspect the sealing surface every 2000 hours. If the gasket shows signs of aging, cracking, or wear on the mating surface exceeding 0.15 mm, replace it immediately. Do not reuse old gaskets to avoid seal failure.

Troubleshooting: Leaks are often caused by gasket aging, loose bolts, or deformation of the mating surface. Replace the gasket and retighten the bolts according to the torque standard. If deformation exceeds 0.2 mm, repair the mating surface.