Frequently Asked Questions About Kenworth W900B/W900L Brake Chambers & Acc.

What's the difference between Type 30 and Type 36 brake chambers for my W900?

Type 30 brake chambers have a 30 square inch effective area and are standard on most W900B/W900L models, while Type 36 chambers provide 36 square inches for heavier-duty applications. Type 30s are typically used on the front axle and lighter rear axles, whereas Type 36s are common on drive axles for trucks hauling heavy loads. Check your existing chamber's data tag or measure the diameter (Type 30 is approximately 6.5 inches, Type 36 is about 7 inches) to ensure proper replacement.

Will aftermarket brake chambers void my truck's warranty or affect DOT compliance?

Quality aftermarket brake chambers that meet FMVSS-121 standards and carry DOT certification will not void your warranty and remain fully DOT compliant. Look for chambers with visible DOT markings and ensure they match your truck's original specifications for stroke length and mounting type. We recommend keeping documentation of the chamber specifications and installation date for inspection purposes.

Do I need to replace the mounting brackets when installing new brake chambers?

In most cases, existing mounting brackets can be reused if they're not damaged or excessively corroded. However, inspect brackets for cracks, elongated bolt holes, or rust damage that could compromise safety. W900B models (1984-1987) and early W900L models may have different bracket spacing than later versions. Always replace mounting bolts and use new lock washers during installation to ensure proper torque retention.

What's the typical lifespan of brake chambers, and what are the warning signs for replacement?

Brake chambers typically last 3-5 years or 300,000-500,000 miles under normal operating conditions. Replace immediately if you notice: air leaks (audible hissing or soap bubble test failures), push rod travel exceeding adjustment limits, visible diaphragm damage, corrosion on the housing, or sluggish brake release. Moisture in the air system significantly reduces chamber life, so ensure your air dryer is functioning properly.

Can I mix long-stroke and standard-stroke brake chambers on my W900L?

No, mixing stroke lengths can cause uneven braking and potential brake timing issues. All chambers on an axle must have identical stroke specifications. Most W900L models use 2.5-inch standard stroke chambers, but some heavy-haul configurations may have 3-inch long-stroke chambers. Check your build sheet or measure the push rod travel at full application to determine your current setup. When upgrading to long-stroke chambers, all chambers on the vehicle should be converted simultaneously.