A key component of the wet brake pack – this is a precision-made brake friction disc by FEROSTEM. It is designed for the drive axles in CATERPILLAR backhoe loaders (e.g., 424D, 428D, 428C, 416B, 428B, 432D, 436C, 438D, 442D) and compactors (CP/CS). Unlike steel plates, this disc features a high-performance Sintered Bronze (SBRZ) friction material and 22 internal teeth (splines) to engage the axle shaft. The special "waffle" groove pattern (SPR/WAG) ensures optimal oil circulation, cooling, and smooth braking.
FEROSTEM is a specialized manufacturer of brake system components, delivering high-quality discs and plates that are precisely engineered to meet the rigorous demands of construction machinery, ensuring safety and durability.
| Brand | Type / Series / Model |
|---|---|
| CATERPILLAR | Backhoe Loaders: 424D, 428D, 428C, 416B, 428B, 432D, 436C, 438D, 442D |
The list above is for reference. We recommend verifying the part number or exact dimensions (OD 204.5mm / 22 Teeth / Thickness 4.8mm) before purchasing.
Servicing wet brakes in a drive axle is an advanced repair. It requires the machine to be securely supported on stands and involves removing heavy components (wheels, planetary hub). A faulty brake system is a fatal hazard. Ensure the system is properly bled after repair.
The friction disc is the executive component in a wet brake pack. It has internal splines (22 teeth) that engage the axle shaft. During braking, a piston compresses the pack, and the friction between these SBRZ discs and the steel separator plates stops the machine. Wear or damage to these discs is the primary cause of brake failure.
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This disc (9R2477/133-7234) is the friction component (made of Sintered Bronze - SBRZ) and has internal teeth (22 splines) that engage the axle shaft. A Separator Plate (e.g., 9R9401 or 9R2476) is the smooth steel disc that goes between the friction discs.
2. What does SBRZ and SPR/WAG mean?SBRZ stands for Sintered Bronze, which is the high-performance friction material used in wet brakes. SPR/WAG (Spring/Waffle) refers to the specific "waffle" groove pattern on the disc's surface, which helps oil circulation and cooling.
3. My machine is a CAT 428B. Which steel plate do I use with this disc?The 428B model typically uses this friction disc (9R2477) in combination with the thinner 9R2476 (2.7 mm) steel plate. Newer models like the 428C/D often use the thicker 9R9401 (4.5 mm) plate. You must verify your machine's specific axle setup.
Have doubts or need confirmation to avoid costly downtime? Call us. Our experts will help you choose the right part to get your equipment back to work as soon as possible.
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Dimension: 204.5x53.3x4.8

















