FAQ’s
Re-arching is a process where a spring pack is set back to its original height by each individual leaf being rolled through our hydraulic rolling machine. A leaf springs arch cannot be brought above its original heat treated height and be expected to hold. Leafs springs can be de-arched to lower a vehicles ride height within reason.
Most are measured for free height then opened up or taken apart so the leafs can be checked for any corrosion and deterioration of the steel that would determine if they are not suitable to survive a rebuild without breaking.
Bushings serve as a vibration isolator. It provides an interface between two parts, damping the energy transmitted through the bushing. A common application is in vehicle suspension systems, where a bushing made of rubber (or, more often, synthetic rubber or polyurethane) separates the faces of two metal objects while allowing a certain amount of movement. This movement allows the suspension parts to move freely, for example, when traveling over a large bump, while minimizing transmission of noise and small vibrations through to the chassis of the vehicle.
For steel encased rubber bushing measure as followed. OD (A), ID (B), width (C), and inner sleeve length (D):
For urethane bushings measure as followed:
Polyurethane (PUR and PU) is a polymer composed of organic units joined by carbamate (urethane) links. While most are thermosetting polymers that do not melt when heated, thermoplastic polyurethanes are also available.
A rubber bushing is comprised of a steel outer sleeve that encases rubber which surrounds a steel inner sleeve.
Both have their positives and negatives and should be chosen wisely for the application of use the vehicle they are being put on is used for. Rubber has a softer durometer and absorbs road noise better. Urethane has a variety of durometers available some of which might have a longer life expectancy but require lubrication and maintenance to prevent noise from movement when in operation.
The Harris bushings are rubber bushings that will install into an application half at a time. The Harris bushings are rubber original equipment replacement parts.
Bushings should be replaced when wear or age deterioration is visible such as cracks or distortion from use.
U-bolts secure the leaf spring and the axle together.
Torque specifications differ depending on grade of bolt as well as diameter and thread size (fine or coarse) on individual bolts.
Grades are a unit to measure tensile strength of the bolts. Grade 5 has a Tensile Strength = 120,000 lbs/in². Grade 8 has a Tensile Strength = 150,000 lbs/in²
U bolts should be replaced whenever they are removed from a vehicle. Threads stretch when torqued and reused u bolts that have been torqued, removed and re-torqued often don’t remain tight.
A progressive design was common in passenger cars over the years and in jeeps or willys and can consist of low leaf counts of three or four leafs or higher in the nine to twelve leaf counts. The leaf count and thickness of each leaf or gauge of material relates directly to the vehicle it is designed for, its primary use and its size and weight. Progressive designs although not exclusively are designed with the intent to provide more wheel travel as well as a smoother and fluent cycling of the suspension. In a progressive design that utilizes a high leaf count of thin material it yields a softer more compliant ride both on highways with expansion joints as well as on trails or washboard roads.
A standard pack typically refers to OEM or very similar. No significant changes to load rating or performance.
Expedition or overland designs combine a significant increase in load rating as well as a performance enhancement in design; they are typically available in a variety of lift heights as well as load ratings to meet a customer’s specific needs depending on their build.
Heavy duty designs are available for most makes and models. They can be helpful for individuals that tow, have campers or with work vehicles such as service beds or in the field vehicles that have everyday weights that compromise the OEM suspensions ability to hold proper ride height. Deaver offers its local customers or anyone willing to take a trip to visit us the option of rebuilding and upgrading their existing leaf springs to handle more weight.
A race pack mostly signifies that it is designed for a vehicle with true race weight like a full bed cage, after-market fuel cell and a spare tire or two.
You only need to reference ordering a race pack if you actually race or have a pre-runner that is built with the same weight modifications as a race vehicle like mentioned in the race pack section of this section.
There are multiple ways to measure a vehicles ride height. First and most importantly make sure the vehicle is on a flat or level surface. Measurements can be taken from the ground at the center of the wheel to bottom of fender or from axle to frame or bump stop on both sides of the vehicle.
A leaf spring is a form of suspension on vehicles that dates back to medieval times, but it was British inventor Obadiah Elliott who patented in 1804 the method of mounting coach bodies on elliptical springs attached directly to the axles, replacing the traditional heavy perch. Before the investment in roads and a national network, goods were transported by pack animal or local cart forcing the carriages and carts to be limited to a horse’s walking pace. Ultimately there was a greater investment in roads and Elliott’s invention ensured stability and carriage travel became a safe smoother ride, subject to road repair and maintenance.
The primary purpose of a leaf spring is to provide support to a vehicle. It not only locates the axle but provides a smoother ride absorbing bumps or pot holes in the road.
First, start with the main leaf measuring from center of front eye along the curvature of the spring to center of center pin {A}, then measure along curvature of the spring from center of center pin to center of rear eye (B). Then measure width of spring. Leaf counts, as well as ID of bushings, are important to determine stationary and shackle bolt diameters. Free height or unloaded arch is measured by taking a line from center of one eye straight across to the center of the other eye and measure from there at the center pin to the top of the main leaf (C). Pack thickness is measured at the center pin (D).
If you can provide your year make and model and the list of measurements discussed in what is the proper way the measure a leaf spring to a spring shop they should be able to determine the type of spring pack you have.
Spring rate is a ratio used to measure how resistant a spring is to being compressed or expanded during the spring’s deflection. The magnitude of the spring force increases as deflection increases according to Hooke’s Law.
Briefly, this can be stated as:
F = − k x {\displaystyle F=-kx\,}
where
F is the force the spring exerts
k is the spring rate of the spring.
x is the deflection of the spring from its equilibrium position (i.e., when no force is applied on the spring)
Load rate is a figure a spring is designed to carry at a certain ride height.
A multi-leaf spring is a design that consists of two or more leafs together.
A mono leaf is a single leaf that works alone and typically is tapered in design being thick in the middle and thinner as it extends out to both ends.
Not if you choose the right spring you put on your vehicle for its application use. While many of Deaver’s popular springs are performance-based in design and not for towing or heavy bed weight we also offer a variety of springs to suit multiple other areas of use, like medium duty, over landing, heavy duty or special use like armored or military applications. The key is to reach out and ask questions before you buy with any Deaver distributor or Deaver so they may suggest or outfit you with the part number that best suits your needs.
Add-A-Leafs are individual leafs short or medium in length designed to be used with existing springs to provide some added height to a vehicle by individuals. They also add load and rate to the spring.
An overload is a par A t of a leaf spring that engages when the primary part of the leaf spring compresses under load to capture and help maintain ride height. In a two-stage design, it is the bottom leaf that is considerably thicker than the primary leafs above it. Upper overloads are a single tapered leaf or multi-leaf design that sits spaced up above the primary pack designed to engage onto stopper brackets mounted to the frame. Upper overloads do not contribute to spring rate when vehicle is empty therefore no negative effect on ride quality.
There are several reasons to replace leaf springs. Oddly enough age isn’t always the reason. Depending on the environment and use they are subjected to leaf springs have a wide range of life spans. Those that are continuously overloaded or put through extreme daily use as well as those that are exposed to moisture and salt from winter roads tend to have the shortest lifespan and will need to be replaced as opposed to dry arid environments. Deaver has an astoundingly high success rate in repairing leaf springs, altering height, increasing or decreasing load as well as simple restoration on existing leaf springs both carried in or shipped to us from afar.