Frequently Asked Questions About Peterbilt 388 CAC Clamps, Boots & Hoses

What size CAC boots and clamps do I need for my Peterbilt 388?

Most Peterbilt 388 models require 4-inch CAC boots for the turbo-to-intercooler connections and 3.5-inch boots for the intercooler-to-intake connections. However, sizes can vary based on your engine model (ISX, C15, etc.) and whether you have aftermarket modifications. We recommend measuring your existing boot diameter or checking your engine specifications. Standard T-bolt clamps typically range from 4.25" to 4.56" for 4-inch boots.

How often should I replace CAC boots and hoses on my Peterbilt 388?

Under normal operating conditions, silicone CAC boots typically last 3-5 years or 300,000-500,000 miles. However, you should inspect them every 6 months for signs of wear including soft spots, bulging, oil saturation, or small cracks. Rubber boots may need replacement every 2-3 years. Frequent boost pressure spikes, extreme temperatures, or oil contamination can significantly reduce lifespan.

What's the difference between silicone and rubber CAC boots?

Silicone boots handle temperatures up to 500?F and maintain flexibility in extreme cold, making them ideal for heavy-duty applications. They resist oil degradation better and typically last 2-3 times longer than rubber boots. Rubber boots are more affordable but have a temperature limit around 250?F and can become brittle over time. For Peterbilt 388 trucks running high boost pressures or in extreme climates, silicone is the preferred choice.

Can I install CAC clamps and boots myself, or do I need special tools?

Installation is straightforward and can be done with basic hand tools. You'll need a socket set (typically 7/16" or 1/2" for T-bolt clamps), flathead screwdriver, and silicone spray lubricant. The process usually takes 30-45 minutes per boot. Key tips: ensure surfaces are clean, use lubricant for easier installation, and torque T-bolt clamps to 50-60 inch-pounds. Avoid over-tightening, which can damage the boot.

Why do my CAC boots keep blowing off even with new clamps?

Boot blow-offs typically indicate underlying issues beyond the clamps themselves. Common causes include: misaligned pipes creating uneven pressure, worn bead rolls on pipes that prevent proper sealing, excessive boost pressure from turbo problems, or using incorrect boot sizes. Check for pipe alignment, inspect bead rolls for damage, verify your boost pressure is within spec (usually under 35 PSI), and ensure you're using constant-torque clamps rather than standard worm-gear clamps for high-boost applications.