Frequently Asked Questions About Kenworth Cabover Brake Chambers & Acc.

What are the correct brake chamber sizes for my Kenworth K100 or K100E?

Most Kenworth K100 and K100E models from 1963-1990 use Type 30/30 brake chambers for the drive axles and Type 24 or Type 20 for the steer axle. However, chamber sizes can vary based on your specific configuration and GVWR. Check the data plate on your existing chambers or consult your truck's build sheet to confirm. Spring brake chambers (parking brakes) are typically Type 30/30 or 36/36 for the rear.

Can I upgrade from standard brake chambers to spring brake chambers on my cabover?

Yes, you can upgrade to spring brake chambers, but it requires additional components beyond just the chambers themselves. You'll need to install a spring brake control valve, modify air lines, add a parking brake dash valve, and ensure your air system has adequate capacity. This conversion typically takes 4-6 hours for an experienced technician and requires proper DOT-approved components rated for your truck's weight.

Why are my brake chambers failing prematurely, and which brands last longest?

Premature failure often results from moisture in the air system, corroded mounting studs, or worn diaphragms. In coastal or high-humidity areas, chambers typically need replacement every 3-5 years. Bendix, Haldex, and MGM are the most reliable brands for cabovers, with Bendix chambers generally lasting 20-30% longer than economy alternatives. Always replace the mounting hardware and use anti-seize on studs during installation.

What's the difference between long stroke and standard stroke chambers for my application?

Standard stroke chambers (2.5 inches) were original equipment on most cabovers, while long stroke chambers (3 inches) provide better braking power and are now DOT-required for many applications. Long stroke chambers require different slack adjusters and may need bracket modifications on pre-1980 cabovers. They reduce brake adjustment frequency by approximately 50% but must be matched with compatible automatic slack adjusters.

How do I identify the correct mounting bracket style for replacement chambers?

Kenworth cabovers use three main mounting styles: two-bolt mount (most common on K100), three-bolt triangular mount (some W900A cabovers), and band clamp style (primarily on older K123 models). Measure the bolt spacing center-to-center and note whether your brackets are welded or bolted to the axle. Offset mounting brackets are common on the passenger side to clear suspension components. Take photos before removal to ensure proper reinstallation angle.