Rockwell American 10K Electric Brake Hub Drum – #99 Spindle – 4.88" Pilot – Blue
Electric brake hub and drum assembly designed for Rockwell American and Quality 10K axles utilizing the #99 spindle configuration. This assembly features a 12-1/4" x 3-1/2" drum and a 4.88" pilot diameter. Bearing races are pre-installed.
Intended for heavy-duty trailer applications where the #99 spindle and associated bearing stack are used. Verify spindle dimensions and bearing sizes prior to installation.
R&P Knowledge Hub
The Rockwell American #99 spindle is commonly found on 10K heavy-duty axles and uses a larger bearing and seal stack than standard 7K or lighter systems. Proper identification of spindle number is critical because hub/drum assemblies are not interchangeable across different spindle series.
The 4.88" pilot diameter and 12-1/4" x 3-1/2" drum configuration indicate a heavy-duty braking system with increased friction surface compared to lighter-duty assemblies. Always confirm spindle journal measurements and seal dimensions before ordering.
Features
- Fits Rockwell American / Quality 10K Axles with #99 Spindle
- 4.88" Pilot Diameter
- 12-1/4" x 3-1/2" Brake Drum
- Bearing Races Pre-Installed
- 8 Lug Configuration
Specifications
| Specification | Details |
| Axle Rating | 10,000 lb |
| Spindle Type | #99 |
| Brake Size | 12-1/4" x 3-1/2" |
| Pilot Diameter | 4.88" |
| Number of Studs | 8 |
Common Associated Components (Not Included)
| Component | Reference |
| Oil Cap (3.75") with O-Ring & Plug | 021-219-00 |
| Outer Bearing | 25580 (1.75" I.D.) |
| Inner Bearing | 28580 (2" I.D.) |
| Seal | OB27377 / 91030 (2.75" x 3.779") |
| Lug Nuts | 8x Coned 5/8" |
Important: Confirm spindle number (#99), pilot diameter, bearing sizes, and seal dimensions before installation. Verify specifications before installation.