SKU SK-CAT3035-ARM
Caterpillar 303.5E Arm Cylinder Seal Kit
completeFull service kitbolt on gland
70 mm bore, 40 mm rod. Bolt-on gland with a face seal. A 70 mm bore reads 2.756 in, which is the classic almost-2.75 metric trap.
What's in this kit
Every seal in the kit, with its material and size.
| # | Qty | Part | Material | ID | OD / cross-section | Height | Shore A |
|---|---|---|---|---|---|---|---|
| 1 | 1 | Rod sealRS-M40-M52-M8 · polypak | Polyurethane | 40 mm (1.5748") | 52 mm (2.0472") | 8 mm (0.315") | 90 |
| 2 | 1 | Buffer sealBS-M40-M52-M6 · buffer | PTFE / NBR | 40 mm (1.5748") | 52 mm (2.0472") | 6 mm (0.2362") | — |
| 3 | 1 | WiperWP-M40-M50-M7 · dust wiper | Polyurethane | 40 mm (1.5748") | 50 mm (1.9685") | 7 mm (0.2756") | 90 |
| 4 | 1 | Rod bushingRB-M40-M44-M10 · guide band | Bronze-filled PTFE | 40 mm (1.5748") | 44 mm (1.7323") | 10 mm (0.3937") | — |
| 5 | 1 | Piston sealPS-M50-M70-M10 · t-seal | Polyurethane | 50 mm (1.9685") | 70 mm (2.7559") | 10 mm (0.3937") | 90 |
| 6 | 1 | O-ringOR-M50-M4 · energizer | Nitrile (NBR) | 50 mm (1.9685") | 3.53 mm (0.139") | — | 70 |
| 7 | 2 | Wear ringWR-M64-M70-M12 · guide band | Bronze-filled PTFE | 64 mm (2.5197") | 70 mm (2.7559") | 12 mm (0.4724") | — |
| 8 | 1 | O-ringOR-M73-M4 · gland seal | Nitrile (NBR) | 73 mm (2.874") | 3.53 mm (0.139") | — | 90 |
| 9 | 2 | Backup ringBU-M73-M80-M2 · backup | Nylon | 73 mm (2.874") | 80 mm (3.1496") | 1.5 mm (0.0591") | — |
Cylinders this kit services
Caterpillar 303.5E Arm Cylinder
- OEM no.
- 285-1660
- Bore
- 70 mm (2.7559")
- Rod
- 40 mm (1.5748")
- Stroke
- 560 mm (22.0472")
- Gland
- bolt on
- Port
- SAE ORB #8
- Rod eye
- spherical bearing
What this fits
| Machine | Serial range | Position |
|---|---|---|
| Caterpillar 303.5E · E Series CR | All serials | Arm / Dipper |
Our kits are dimensional equivalents built from seals we buy in. They fit and replace the original. They are not OEM parts and carry no OEM branding.
Not finding it?
Not sure this is right?
Check it with a caliper before you buy — how to measure bore, rod and stroke covers the mistakes behind most wrong orders. Send us the numbers and a photo of the old seals and we’ll confirm the fit before you spend anything.
Request a kit