How to Identify 14 Bolt Drum Brake Hubs
Understanding Your 14 Bolt Full Float Axle Configuration
When working with 14-bolt full-float disc brake conversion kits, proper hub identification is essential for maintenance and replacement. Many enthusiasts purchase these axles without brakes installed and need guidance on determining which hub style they have. This comprehensive guide will help you accurately identify your 14-bolt drum brake hubs using specific measurements and visual characteristics.
Identifying Single Rear Wheel (SRW) Hub Styles
Older Style SRW Hubs (1973-2000)
The older generation 14 bolt SRW hub measures approximately 1.75 inches (1 ¾ inches) long from the wheel mounting surface (WMS). The distinguishing feature of this design is a single step at the wheel mounting surface, making it easy to recognize. This configuration remained consistent throughout its production run from 1973 to 2000.
Newer Style SRW Hubs (1988-2000)
The newer SRW 14-bolt hub design measures approximately 2.625 inches (2 5/8 inches) from the wheel mounting surface, making it nearly an inch longer than its predecessor. The key identifying feature is two distinct steps at the wheel mounting surface instead of one. This newer style was manufactured from 1988 through 2000, overlapping with the older design for twelve years.
Dual Rear Wheel (DRW) Hub Characteristics
The 14-bolt dually hub measures about 3.875 inches (3 7/8 inches) long from wheel mounting surface, also used on cab and chassis configurations, maintained remarkable consistency throughout its production life. From 1973 to 2000, this hub design remained unchanged, making identification straightforward. A critical distinction of the DRW setup is that the drum is always positioned behind the hub on the 14 bolt dually axle, unlike some other configurations.
Why Accurate Hub Identification Matters
Knowing your exact hub type is crucial when ordering replacement parts. The dimensional differences between older and newer SRW styles mean components are not interchangeable. Using these measurement techniques and visual cues ensures you purchase the correct replacement hub for your specific 14 bolt axle configuration, saving time and preventing compatibility issues.
FAQs: How to Identify 14-Bolt Drum Brake Hubs
Q: How can I tell if I have an older or newer style 14 bolt SRW hub?
A: Measure the hub length from the wheel mounting surface. Older style hubs measure 1.75 inches with one step, while newer style hubs measure 2 5/8 inches with two steps at the mounting surface.
Q: Did the 14-bolt dually hub design ever change?
A: No, the 14 bolt dual rear wheel hub remained unchanged from 1973 to 2000, maintaining the same design throughout its entire production run.
Q: What years did GM produce both old and new style SRW hubs?
A: Both styles overlapped from 1988 to 2000, with the older style running from 1973 to 2000 and the newer style from 1988 to 2000.
Q: Where is the drum located on a 14 bolt dually axle?
A: On all 14 bolt dually axles, the drum is always positioned behind the hub, which is consistent across all production years.
Q: Are cab and chassis hubs the same as dually hubs?
A: Yes, the 14-bolt dual rear wheel hub used on standard dually trucks is identical to the hub used on cab and chassis applications.