Leaf springs are semi-elliptical arms made from steel or composite materials that support the weight of a car or truck. They were popular in cars until the arrival of front-wheel drive vehicles, but still form the suspension for many heavy-duty vehicles, such as trucks and vans, as well as sports cars. Understanding how leaf springs work and recognising signs of damage can help car owners maintain their vehicles to keep them working correctly.
Purpose of leaf springs
Leaf springs date back to the days of horse-drawn carriages when people used leather straps to support the carriages. In modern cars, leaf springs attach directly to the drive axle with shock absorbers connected to clamps that hold the springs in place. Leaf springs are part of a car's suspension system and absorb energy as the vehicle moves across uneven roads by helping the tyres to maintain contact with the ground.
Leaf springs are similar to coil springs and torsion bars. They control axle dampening and chassis rolling, while protecting the vehicle from lateral forces. This improves the handling of the car for the driver and gives passengers a smoother ride.
Vehicle manufacturers originally used leaf spring systems because of the simplicity of the design; they only needed to bundle together pieces of steel and attach them to the car. Despite advances in technology and the advent of coil springs and torsion bars, leaf spring suspensions remain popular on heavy-duty vehicles because they distribute the load more evenly across the entire chassis rather than at a single insertion point. Leaf springs are also sturdier than flexible coil springs. Although this increases the vibrations passengers feel while travelling, it gives leaf springs the ability to withstand greater forces of weight from the vehicle.
Types of leaf springs
Consumers have four options when choosing leaf springs, categorised by material and shape. These types of leaves have distinct advantages and disadvantages that indicate which vehicles should use them.
Fibreglass or steel
Fibreglass springs consist of plastic fibres and resin, and are the lightest type of leaf spring available. Car manufacturers that aim to reduce the weight of a vehicle to enhance performance choose fibreglass leaf springs. Unlike steel used in traditional leaf springs, the composite material does not withstand heat and road debris. Fibreglass springs frequently appear on Audis and other luxury cars.
The design of multi-leaf springs combines flat bars of diminishing lengths in a bundle held together by bolts and clips. Each leaf has a specifically selected length that supports the strip above it to provide additional support for the system. This makes multi-leaf springs ideal for heavy vehicles that need a spring able to withstand extra weight.
Mono-leaf springs have a single heat-treated steel plate that tapers at each end. This type of spring is lighter than multi-leaf springs, but it does not provide the same level of protection. For this reason, many car manufacturers stopped using mono-leaf springs in the 1970s.
Parabolic leaf springs combine features of mono and multi-leaf springs into a parabolic curve. This design combines two or more tapered steel plates into a bundle. Most parabolic leaf springs use fewer plates than multi-leaf springs, so they are lighter, but safer than mono-leaf springs.
Signs of damaged leaf springs
Although leaf springs are durable parts that usually last for several years, they suffer damage over time from exposure to weather and corrosive materials. Owners need to check left springs regularly for signs of erosion, rust, or cracks and replace them when they notice any damage.
Obvious signs that it is time to replace leaf springs are a sagging vehicle and a truck or van that looks like it is level to the ground. Both of these scenarios indicate failing leaf springs that no longer support the vehicle's weight. When inspecting leaf springs, owners should check the bushings at the point where the leaf springs attach to the chassis for signs of wear.
How to buy leaf springs on eBay
Whether you want to replace or upgrade your vehicle's suspension, finding replacement leaf springs for your car or truck is easy on eBay. To locate them, enter the type of leaf spring that you wish to buy in the search box. As you review the listings, inspect pictures closely to make sure the springs do not have obvious signs of damage and note whether the seller includes the bolts and clips you need to install the parts.