How to Determine If Your Leaf Springs Are Weakby Philip PoweUpdated July 12, 2023
Check for Leaf springs fractures, rust, or signs of wear. Leaf springs are part of a vehicle's suspension system.
If the springs are worn out, it is very easy for the average car owner to know. Unless you are a certified mechanic, it is not recommended that you attempt to replace them.
Leaf springs are the long, flat springs under the rear end of a car or truck. They are designed to be a load-bearing spring more than a suspension or coil spring, but they might break easily because of the corrosion on all of its moving parts. These suspension parts are also important if you are using a vehicle to tow. These springs will hold the load.
If you are planning on towing heavy loads, it is advisable to have an extra leaf placed in the springs.
Tests and Symptoms of Bad Leaf Springs
1. Park on level surface
Park the car on a level surface and center the level on the roof of the car. If the car is out of level in the back of the vehicle, then you might have broken leaf springs. To test this, push down on the rear of the car. If it goes down easily, then the vehicle’s suspension may be bad. If it comes up slowly, the shock absorbers are still good, so you will need to look deeper into the problem.
Take special care when raising your vehicles to replace or check the leaf spring suspension; you must lift the rear only with a jack or hoist placed under the frame rail crossmember, which is located to the aft of the rear axle.
2. Inspect Leaf Springs
Look under the car at the truck’s leaf springs. If they are rusted, have bits of the rubber bush missing or if there are obvious signs of wear and tear, then you may want to have them replaced at a repair shop. The vehicle’s leaf springs will be the long stacked set of metal beams that run parallel to the side of the vehicle’s frame. If you see one of these beams broken, you will have to have them replaced.
3. Take the car off-roading
Take the car off-roading and see if it’s a rough ride. If the vehicle bounces or seems as if it is going to skid from side to side, then the leaf springs are bad. They are causing the shocks to try to absorb too much punishment. The shocks are designed for relieving these bumps, not taking the whole impact. This can potentially affect wheel alignment or other rear suspension components in your car.
4. Attach a payload to the trailer hitch.
Attach a payload to the trailer hitch. If the vehicle is used for towing, the best way to check if the rear leaf springs are the problem is to see if the load is forcing the rear of the vehicle down. If the ride height is off, you are either overloading or you need new leaf springs. If it has never sagged, then you need replacement leaf springs.
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Philip Powe started writing in 1987 for St. Louis area newspapers. He has since written for "St. Clair County Historical Society Journal" and the "American Association of State and Local Historians Journal." Concentrations are in home and garden, philosophy and history. Powe holds a Master of Arts in intellectual history from Southern Illinois University.