Rear Trailing Arm

Rear Trailing Arm

A rear trailing arm is a major part of a vehicle’s suspension. It is widely used in lightweight trucks, eliminating the need for heavy leaf springs. It connects the rear axle of a vehicle to its frame or body, allowing the axle and the rear suspension to move up and down to handle road imperfections. It can also support coil springs and shock absorbers.

Depending on your vehicle, you may have two or more trailing arms per axle. Regardless of their quantity, rear trailing arms provide better control over the rear axle, while increasing its travel. That’s why many aftermarket suspension kits, especially lifted ones, come with rear trailing arms. Made from high-grade steel, rear trailing arms can last the life of a vehicle. The only component of a rear trailing arm assembly that may need your attention is bushings. Being exposed to heavy loads, they can wear out, so they must be inspected from time to time and replaced if necessary.

A bad trailing arm or bushing can cause a number of problems with your rear suspension, providing several warning signs, including the following:

Abnormal noises coming from the rear axle

Worn-out bushings may alert you of the problem, causing a clunking noise when your vehicle hits a bump or pothole, or during rapid acceleration or braking. The same issue may appear when going around a turn. If bad bushings are not addressed, they may cause damage to rear trailing arms.

Your vehicle can’t move in a straight line

Since trailing arms are designed to secure and support the rear axle, bad bushings or damaged trailing arms can cause the axle to move erratically when hitting a bump or going over a rough surface. Your rear wheels may also change the direction of your vehicle, so you have to compensate for that with your steering wheel.

Uneven or improper tire wear

Failed bushings or broken trailing arms can put rear wheels out of the alignment. To keep the vehicle running into the desired direction, your vehicle will have to drag rear tires down the road. As a result, your tires will wear unevenly and much faster than they should.

Different ride height on the sides

Worn-out bushings on one of the sides can cause the coil spring to lift that side a bit higher compared to the other one. If this is not addressed, you’ll experience steering problems and uneven tire wear on one of the sides. 

Rear trailing arm troubleshooting and replacement

A trailing arm is designed to last the lifetime of a vehicle, so its failures almost never happen. However, it can get damaged in a road collision. If so, a bad trailing arm must be replaced with a brand-new part. Besides, in many cases it can be cheaper to replace an entire trailing arm assembly than to remove old bushings and to install new ones.

Before replacing trailing arm bushings you must be certain sure you have all necessary equipment to do the trick. In most cases you’ll need a hydraulic press to remove existing bushings. That’s why it’s better to leave this job to a professional mechanic. He or she may recommend you to install aftermarket bushings if they are more durable and can last longer. 

If you’re going to install a lift kit, your rear trailing arms should be adjusted to keep the vehicle running smoothly. A four-wheel alignment is also recommended to avoid steering problems and uneven or excessive tire wear.