Description
Product Overview
The Kenworth 4-Leaf Spring 59408 is a front leaf spring with four leaves. It is listed under part number 59408, also referenced as 59-408, and is made for Kenworth applications. Published specifications list a 4-inch spring width, 27.25-inch long and short ends and a 5,900-pound spring capacity at the pad.
A leaf spring carries a major part of the suspension load. When the existing spring is cracked, sagging or otherwise worn out, replacing it is a much better option than trying to keep a damaged spring in service.
What the Part Does
The leaf spring forms part of the truck’s suspension and carries the weight of the vehicle while the truck is moving. It also flexes as the truck travels over uneven roads, helping absorb some of the movement coming through the front suspension.
This 59408 is a four-leaf spring with a full-taper design. The spring has standard eyes on both ends, with the available specifications also listing threaded spring eye bushings.
Common Problems This Spring Replaces
A damaged or worn leaf spring can show up in several ways. The truck may sit unevenly, the suspension may sag or you may notice visible damage to one of the spring leaves.
Cracks, broken leaves and excessive corrosion are also reasons to take a closer look at the spring. Any significant damage to a load-bearing suspension spring should be taken seriously rather than ignored.
If one spring has failed, inspect the other side and the surrounding suspension hardware as well. This can reveal whether the problem is isolated or part of wider suspension wear.
Why Replacement Matters
A damaged spring can change how the truck carries weight and how the front suspension sits. Leaving a cracked or broken spring in service can also put extra stress on other suspension components.
Replacing the spring restores the main load-carrying component at that position. It is also a good time to inspect the spring eyes, bushings, pins and related mounting hardware.
Related suspension part: If you’re working on the spring assembly, take a look at our Peterbilt Spring 75-212 for another heavy-duty spring option in our inventory.
Compatibility and Fitment
The 59408 / 59-408 spring is listed for Kenworth front suspension applications. Available specifications identify four leaves, a 4-inch width and 27.25-inch dimensions at both the short and long ends.
Always compare the part number and spring specifications with the spring currently on your truck before ordering. If you need to confirm fitment for a particular Kenworth, contact us with the truck information and existing spring number.
You can also browse our Aftermarket Truck Parts for additional suspension components and replacement parts.
Installation and Service Notes
Leaf spring replacement is suspension work, so the truck needs to be properly supported before the spring is removed. The spring and its mounting hardware can carry substantial load.
During installation, inspect the spring seats, U-bolts, bushings and mounting points. If another component is worn or damaged, replacing it at the same time can save you from taking the suspension apart again later.
Follow the service procedure for the specific truck and verify all mounting hardware is properly secured before returning the truck to the road.
Use Case
The 59408 is a replacement front leaf spring for Kenworth applications where the original spring is damaged, worn or no longer suitable for service. It can also be used during a larger front suspension repair when the spring assembly is already being serviced.
For fleet maintenance, checking the springs during regular suspension inspections can catch cracks or other visible problems before they turn into an unexpected roadside repair.
About Us
We’re a family-owned group of Peterbilt dealerships dedicated to getting you the parts you need quickly and affordably. Whether you’re looking for Paccar OEM parts, reliable aftermarket replacements, or popular upgrades like seats and filters, we make it easy to keep your truck running and on the road. If you don’t see what you need online, just give us a call or send an email — chances are we can get it. We pride ourselves on fast service, fair prices, and being a partner you can depend on when downtime isn’t an option.
FAQs
How many leaves does the 59408 spring have?
The 59408 is a four-leaf front spring. It is listed with a 4-inch width and a 5,900-pound spring capacity at the pad.
What truck brand is the 59408 spring for?
The 59408 is listed for Kenworth applications. Always compare the part number and spring dimensions with the existing spring before ordering.
What are the dimensions of the 59408 spring?
The published specifications list a 4-inch width with 27.25-inch short and long ends. The spring arch is listed at 5.87 inches.
What should I replace or inspect with a leaf spring?
Check the U-bolts, spring eyes, bushings, pins and mounting points while the spring is being replaced. Worn hardware can cause problems even after a new spring is installed.
Where can I find other truck suspension parts?
You can browse our Aftermarket Truck Parts for additional suspension springs, bushings and other heavy-duty replacement components.
