Frequently Asked Questions About Mack R Truck Leaf Springs, Hangers & Acc.
What years and models of Mack R trucks do these leaf springs fit?
Our Mack R truck leaf springs are designed to fit R-Model Macks from 1966 through 2004, including R600, R685, R686, R688, RD600, RD688, and RD690 models. However, spring configurations can vary based on your truck's original specifications, suspension type (Mack, Hendrickson, or Neway), and whether you have a single or tandem axle setup. We recommend checking your existing spring's part number or contacting us with your VIN to ensure proper fitment.
How difficult is it to replace leaf springs on a Mack R truck, and what tools are required?
Replacing leaf springs requires moderate to advanced mechanical skills and typically takes 4-6 hours per axle. Essential tools include a heavy-duty floor jack or truck lift, jack stands rated for commercial vehicles, impact wrenches, spring compressors, and torque wrenches capable of 450-500 ft-lbs. You'll also need to support the frame properly and may need to disconnect brake chambers and shock absorbers. Due to the weight and safety concerns, many operators choose professional installation, which typically runs $400-800 per axle in labor.
What's the difference between OEM and aftermarket leaf springs for Mack R trucks?
OEM Mack leaf springs are manufactured to original factory specifications with precise arch measurements and spring rates. Aftermarket options can vary in quality - premium aftermarket springs from manufacturers like Dayton Parts or Triangle Spring use similar materials and heat treatment processes as OEM but may cost 30-40% less. Lower-cost imports may use different steel grades or coatings that can affect longevity. We carry both OEM and trusted aftermarket brands, clearly marking the manufacturer and warranty terms for each product.
How do I know when my leaf springs need replacement versus just new bushings or hangers?
Signs that springs need replacement include visible cracks, broken leaves, permanent sagging (truck sits lower than spec height), or leaves that have shifted out of alignment. If your truck pulls to one side, has uneven tire wear, or rides roughly but the leaves look intact, you may only need new bushings, shackles, or hangers. Measuring your suspension height against Mack's specifications for your model is the best diagnostic method. Spring eye bushings typically need replacement every 200,000-300,000 miles, while springs themselves can last 500,000+ miles with proper maintenance.
What weight capacity and spring rate options are available for different Mack R truck applications?
Mack R truck leaf springs come in various capacities ranging from 12,000 to 23,000 pounds per spring, depending on your application. Standard highway tractors typically use 20,000-pound capacity springs, while heavy-haul or vocational trucks may require 23,000-pound or multi-leaf progressive rate springs. Spring rates vary from 250-500 pounds per inch of deflection. Choosing the correct capacity affects ride quality, load handling, and component longevity. Your door jamb sticker or Mack build sheet will specify the original spring capacity for your truck.
