Hydraulic Boom Cylinder Seal Kits for Caterpillar 320B & 320BL Excavators
Hydraulic fluid leaks on your Caterpillar 320B or 320BL excavator can lead to drift, reduced lifting power, and expensive downtime. Servicing the boom cylinders with a dedicated seal kit restores full hydraulic pressure and stops fluid bypass.
Because Caterpillar manufactured multiple cylinder configurations for the 320B series based on attachment type (standard vs. mass excavation) and serial number breaks, matching the exact Cylinder Group Number, Rod Diameter, and Bore Diameter is crucial to getting the correct fit.
Below is a detailed cross-reference chart for CAT 320B / 320BL Boom Cylinder Seal Kits.
CAT 320B / 320BL Boom Cylinder Seal Kit Reference Guide
| Cylinder No. (Cylinder Group) | Rod Size (Diameter) | Piston Size (Bore Diameter) | Aftermarket Seal Kit Part No. |
| 1183953 | 100 mm | 140 mm | CTC-1373764 |
| 1183955 | 100 mm | 140 mm | CTC-1373764 |
| 1184023 | 85 mm | 120 mm | CTC-1373763 |
| 1184128 | 85 mm | 120 mm | CTC-1184131 |
| 1195425 | 75 mm | 110 mm | CTC-1195435 |
| 1232081 | 105 mm | 150 mm | CTC-1373767 |
| 1336770 | 100 mm | 140 mm | CTC-1336823 |
| 1589058 | 85 mm | 120 mm | CTC-1589092 |
| 1842614 | 95 mm | 160 mm | CTC-1884457 |
Premium Features of Replacement Seal Kits
- High-Temperature Polyurethane (PU) & NBR Seals: Engineered to withstand extreme hydraulic operating temperatures and rapid pressure spikes without losing elasticity or tearing.
- Complete Overhaul Contents: Kits typically include U-cup rod seals, buffer rings, piston seals, wear rings, wiper/dust seals, and heavy-duty O-rings for complete head and piston resealing.
- Contamination Protection: Advanced wiper geometry keeps out dust, mud, sand, and ambient job site debris, preventing internal cylinder wall scoring.
Steps to Verify Before Ordering
- Locate the Cylinder Stamped Number: Check the outer barrel or head gland assembly on your CAT 320B/320BL boom cylinder for the stamped OEM cylinder number (e.g., 1183953, 1232081, 1842614).
- Measure Rod and Bore Dimensions: Measure the outer diameter of the chrome piston rod and the inner diameter of the cylinder tube using calipers to confirm match (e.g., 100mm rod / 140mm bore).
- Verify Machine Serial Prefix: Confirm your machine’s serial number prefix (e.g., 1XS, 2AS, 3MR, 8ES, 6CR) to ensure compatibility with standard vs. heavy-duty cylinder groups.
