Description
Product Details
| Seal Kit | 3750731 |
| Existing Cylinder Reference | 1438158 — retain as an unconfirmed reference until checked against the machine serial-specific CAT parts diagram |
| Brand | CAT |
| Kit Type / Application | Rod Seal Kit — 306D Boom Cylinder |
| Rod Diameter | 55 mm (2.17 in), per CAT |
| Bore Diameter | Not specified in CAT's public listing for this kit; existing 100 mm value is not confirmed by the cited source. |
| Product Type | Hydraulic Cylinder Rod Seal Kit |
| CAT-Compatible Models | Mini Hydraulic Excavators: 305.5 GC, 306.5, 306, 306E2, 305.5E2 |
| Kit Components Listed by CAT | Lip-type seal (1), retaining rings (2), O-rings (3), seal assembly (1), buffer ring (1), bearing (1), backup rings (3). |
| Fitment Verification | Confirm the exact cylinder group and machine serial number before ordering. |
Source: CAT Parts Store — 375-0731. The prior nominal bore is not treated as confirmed because the CAT kit page does not publish it.