Frequently Asked Questions About Mack CH/CHN/CHU Truck Air Springs & Level Valves

Which air springs fit my specific Mack CH, CHN, or CHU model year?

Air spring compatibility depends on your truck's suspension configuration rather than just the model year. Mack CH/CHN/CHU trucks from 1988-2009 typically use either Firestone W01-358-9622 or Goodyear 1R11-221 air springs for the rear suspension. However, you'll need to verify your specific suspension type (Mack Camelback, Hendrickson, or Neway) and check the part number on your existing air spring. The number is usually stamped on the top plate or rubber body. For front air springs, most models use the Firestone W01-358-9191 or equivalent.

How difficult is it to replace air springs and level valves, and what tools do I need?

Replacing air springs requires intermediate mechanical skills and typically takes 2-3 hours per axle. You'll need jack stands rated for commercial trucks, a floor jack, basic hand tools, and ideally an impact wrench. The main challenges include safely supporting the truck's weight, disconnecting air lines without damaging fittings, and properly torquing the mounting bolts to 65-75 ft-lbs. Level valve replacement is generally easier but requires careful adjustment afterward to maintain proper ride height. Many drivers recommend having a helper to monitor ride height while making adjustments.

What's the difference between OEM and aftermarket air springs for reliability?

Quality aftermarket air springs from Firestone, Goodyear, and Continental perform comparably to OEM parts when properly installed. These manufacturers often supply OEM parts to Mack. The key difference is usually price - aftermarket options typically cost 30-40% less. Look for air springs with reinforced rubber compounds rated for -40?F to 200?F, corrosion-resistant steel plates, and a minimum 100,000-mile warranty. Avoid no-name brands as they often use thinner rubber that develops cracks within 12-18 months.

How do I know if my level valve needs replacement versus just adjustment?

A level valve needs replacement if your truck won't maintain consistent ride height, constantly releases air, or takes more than 30 seconds to level after loading. Before replacing, check for kinked linkage, worn bushings, or loose mounting bolts - these cause 60% of leveling issues. To test the valve, manually move the arm through its full range with the engine running. You should hear air flow when moving up and exhaust when moving down. If the valve sticks, leaks internally, or doesn't respond smoothly, replacement is necessary. Adjustment alone won't fix internal valve problems.

Can I upgrade to a different style air spring for better ride quality or load capacity?

Yes, but upgrades require matching the mounting style and height specifications. Rolling lobe style air springs generally provide better ride quality than convoluted bellows types but may require different mounting brackets. For increased load capacity, you can upgrade from standard 1R11-221 springs (rated at 20,000 lbs) to heavy-duty 1R12-221 springs (rated at 24,000 lbs) if your suspension components can handle the extra capacity. Always maintain the same spring type and capacity on both sides of an axle. Consult your suspension manufacturer's guidelines before upgrading to ensure compatibility with your specific setup.