Frequently Asked Questions About Kenworth W900B/W900L Frame Nut Covers

Will these frame nut covers fit my specific Kenworth W900B or W900L model year?

These frame nut covers are designed to fit most Kenworth W900B models from 1987-2019 and W900L models from 1987-present. However, fitment can vary based on your specific frame configuration and any aftermarket modifications. We recommend measuring your frame bolt spacing before ordering. Standard frame bolts are typically 33mm (1.3 inches) or 1.5 inches in diameter. If you're unsure, contact us with your VIN and we can help verify compatibility.

What's the difference between chrome plastic and stainless steel frame nut covers?

Chrome plastic covers are lightweight, cost-effective, and provide good appearance for trucks that see lighter duty or are garaged regularly. They typically last 2-3 years before showing wear. Stainless steel covers are significantly more durable, resistant to road salt and chemicals, and maintain their finish for 5+ years even in harsh conditions. While stainless costs more upfront, many drivers find the longevity worth the investment, especially for trucks operating in northern climates or heavy-duty applications.

How difficult is the installation, and what tools do I need?

Installation is straightforward and typically takes 1-2 hours for a complete set. Most covers are push-on style that snap over existing frame nuts. You'll need a rubber mallet for secure fitment and possibly some dish soap as a lubricant for easier installation. Some drivers use a heat gun in cold weather to make plastic covers more pliable. No drilling or permanent modifications are required. The biggest challenge is usually accessing nuts in tight spaces near the fuel tanks or air lines.

Do these covers come in different styles, and which threads do they fit?

Frame nut covers are available in several styles including standard dome, pointed spike, and flat-top designs. Most covers are universal-fit with flexible tabs that accommodate both standard (SAE) and metric threads. They typically fit M20, M22, M24 metric threads and 3/4", 7/8", 1" SAE threads. Pointed styles add 2-3 inches of projection from the frame, so ensure you have adequate clearance from tires and air lines before ordering spike-style covers.

How do I keep frame nut covers from falling off, especially in winter conditions?

To prevent covers from coming loose, ensure frame nuts are clean and free of rust or grease before installation. Apply a small amount of clear silicone adhesive inside the cover for extra security without making future removal difficult. In winter, road salt and ice buildup can cause covers to loosen - regular washing helps prevent this. For trucks operating in extreme conditions, consider thread-on style covers instead of push-on models, as they provide more secure attachment but require removing the frame nuts during installation.