Improper control arm replacement and calibration can cause severe damage to the car. Many people may be puzzled about why they are always told that a damaged car control arm needs to be replaced in pairs when they go to a repair shop? Can you replace just one control arm? Maybe not much as you think someone wants to make that extra bucks.
Should I change both control arms?
In three cases, the control arms must be replaced in pairs. Otherwise, you will have to face a secondary repair.
1. Wear and tear
Control arms are usually made from aluminum or steel. They are strong and can withstand a lot of abuse. However, the rubber bushings within them are weak. The rubber bushings can become brittle, dry rotted, cracked, or split. If this happens, the bushings will not hold the arm in the correct position. Customers might experience excessive tire wear or excessive NVH. The steering wheel could also appear off-center while the vehicle moves straight down the road.
While worn out or torn bushings will be the most common reason for replacing a control arm, others may ask, "should I change both control arms" This is similar to asking, "Why should I change the brake pads on both the front and back of my car?"
2. Non-serviceable components
Some control arms might have ball joints that are permanently fixed in place. These control arms are crucial for vehicle alignment and should be returned in pairs. The ball joints are usually not removable, so replacing the whole control arm is necessary. Check the ball joint boot for cracks or dry rotting and leaking grease. If the ball joint becomes loose inside, it should be replaced.
3. Physical damage
It must be replaced if a control arm is bent or damaged by a tow truck's impact or careless driver. Here is an example of a control arm made from steel that was severely damaged by road debris. It is best to replace both control arms in such a situation. It is impossible to know the condition of the bushings on the other arm. They will perform differently from the ones inside the new arm.
So now, walking into a car repair shop, do you know why control arms should be replaced in pairs?