| Parameter | Specification |
|---|---|
| COGENG Part Number | 991/20028 (99120028) |
| OEM Equivalent | JCB 991/20028, JCB 99120028 |
| Product Type | Hydraulic Cylinder Seal Kit |
| Application | Boom, Bucket, Arm, Stabilizer, Steering cylinders |
| Kit Type | Complete overhaul seal kit |
| Compatible Models | Multiple JCB excavator, backhoe loader, and telehandler models |
| Brand | Part Number |
|---|---|
| COGENG | 991/20028, 99120028 |
| JCB | 991/20028, 99120028 |
| Interchange | 991/20029, 991/20030, 991/00145, 991/00147, 991/10142 |
| Component | Material Grade | Hardness | Temperature Range |
|---|---|---|---|
| Piston Seals | Polyurethane (PU) | 90-92 Shore A | -35°C to +110°C |
| Rod Seals | NBR + PTFE coating | 85 Shore A | -40°C to +120°C |
| Wiper Seals | Polyurethane (PU) | 88-90 Shore A | -35°C to +100°C |
| O-Rings | HNBR (Zetpol) | 70 Shore A | -40°C to +150°C |
| Wear Rings | PTFE + Bronze filler | — | -50°C to +200°C |
| Backup Rings | Nylon 66 (Glass filled) | — | -40°C to +120°C |
| Buffer Seals | Polyurethane | 90 Shore A | -35°C to +110°C |
| Parameter | Rating |
|---|---|
| Maximum Pressure | 350 bar (5,075 psi) |
| Operating Temperature | -40°C to +120°C |
| Fluid Compatibility | Mineral oil, synthetic hydraulic fluids, biodegradable oils |
| Seal Speed Rating | Up to 0.5 m/s |
| Service Life | 5,000+ operating hours |
| Item | Description | Quantity | Material |
|---|---|---|---|
| 1 | Piston Seal (Primary) | 2 | Polyurethane |
| 2 | Rod Seal (Step-cut) | 2 | NBR + PTFE |
| 3 | Wiper Seal (Double-lipped) | 2 | Polyurethane |
| 4 | Buffer Seal | 2 | Polyurethane |
| 5 | Wear Ring (Piston) | 2 | PTFE Composite |
| 6 | Wear Ring (Gland) | 2 | PTFE Composite |
| 7 | O-Ring (Gland to barrel) | 2 | HNBR |
| 8 | O-Ring (Piston to rod) | 2 | HNBR |
| 9 | O-Ring (End cap) | 4 | HNBR |
| 10 | Backup Ring (Various sizes) | 4 | Nylon 66 |
| 11 | Dust Seal (Rod wiper) | 2 | Polyurethane |
| Cylinder Type | Typical Application | Common Functions |
|---|---|---|
| Boom Cylinder | Excavator / Backhoe boom | Raise/lower boom |
| Bucket Cylinder | Excavator bucket / Backhoe bucket | Bucket curl/dump |
| Arm Cylinder | Excavator dipper arm | Extend/retract arm |
| Stabilizer Cylinder | Backhoe loader stabilizers | Level machine |
| Steering Cylinder | Telehandler / Wheel loader steering | Steering control |
| Lift Cylinder | Telehandler boom lift | Raise/lower forks |
| Equipment Type | Model Series |
|---|---|
| Backhoe Loaders | 3CX, 4CX, 5CX, 3DX, 4DX |
| Excavators | JS130, JS160, JS200, JS210, JS220, JS240, JS260, JS300, JS330 |
| Telehandlers (Loadall) | 505-19, 506-36, 508-40, 510-40, 520-55, 526-56, 531-70, 535-95 |
| 8000 Series | 8050, 8052, 8060, 8065, 8080 |
| NO | Number | Name | Qty |
| 1 | **** | 'See Remark' 332/H7041 End Cap Assembly |
1 |
| 2 | :590/40858 | Piston Rod Assy | 1 |
| 2A | :1211/0021 | Bush | 1 |
| 3 | :595/27823 | Head Piston | 1 |
| 4 | :826/01184 | Dowel retaining | 1 |
| 5 | :2411/7940 | Ring Wear | 2 |
| 6 | :2411/ 1151 | Seal | 1 |
| 7 | :572/70047 | Cylinder | 1 |
| 7A | :809/00183 | Bearing 2 .5" x 75 x 140 | 2 |
| 11 | :1450/0001 | Nipple Grease, Straight 1/8 BSP | 2 |
| 20 | **** | Paint Consumable Black | 1 |
| 42 | :816/90502 | Cap special Europower | 2 |
| 50 | 991/20028 | Kit-seal | 0 |
Q: What is the warranty coverage for this seal kit?
A: COGENG provides a standard 12-month warranty against manufacturing defects from the date of installation. Proof of purchase and installation by a qualified technician are required. Warranty does not cover seal failure caused by contaminated hydraulic fluid, improper installation, cylinder barrel or rod surface damage, or use on incompatible equipment.
Q: What should I inspect before installing the new seal kit?
A: Before installation, carefully inspect the cylinder rod for scratches, pitting, or chrome plating damage, and check the cylinder barrel for scoring or internal wear. Damaged surfaces will cause premature seal failure. Recondition or replace worn components and thoroughly flush the hydraulic system to remove all contaminants before reassembly.
Q: How is the seal kit packaged for shipping?
A: Each COGENG 991/20028 seal kit is sealed in a heavy-duty, moisture-resistant poly bag with individual seal compartmentalization to prevent damage during transit. All components are labeled for easy identification during reassembly. The kit is then packed in a sturdy outer carton for added protection.
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