A vehicle when driven down a straight flat road should go straight ahead with a slight drift to the right for safety. A slight right hand drift was designed into US and other left hand drive vehicles to avoid head on collisions when a driver falls asleep or is rendered unconscious. In right hand drive countries a car is designed to have a slight left hand drift for the same reason. If the car has an excessive pull to the left or right while driving or braking, this could be a signal that there is a problem with a worn or failed steering orsuspension component. We have listed common reasons for this condition below:
Troubleshooting Procedure and Inspection
Inspect Front Strut Rod Bushings - If strut rod bushings are worn or missing it will allow the suspension control arm to shift while driving and braking. When inspecting suspension bushings look for cracking, dilapidation or shiny surfaces showing that suspension components have moved. When bushings wear they can allow the suspension components to move causing the car to dart from one side or the other when braking or traveling over bumps in the road.
Cracked Strut Rod Bushing
Inspect Upper - Lower Ball Joints - The ball joints act as a universal joint that is connected to solid suspension arms and spindles. Ball joints have little to no clearance to hold suspension components in-line while steering or traveling over rough roads. If the ball joints become worn they will allow suspension components to move out of line causing the car the wander from one side to the other. When checking the suspension components lift the car slightly but leave the wheels on the ground, this will take pressure a off of the ball joints to allow proper inspection. (Heavy pressure on ball joints will make it difficult to test for play in the ball joint). Use a large pry bar and insert between the ball joint components rock back and forth while checking for excessive movement in the ball joint. Little to no play should be observed. If excessive play is observed the ball joint has worn and needs to be replaced.
Check for Tire Tread Separation - The tires on your car are designed with many separate layers that can become dislodged internally. The tire will act one way when the car is driven normally, a shift can occur within the tire when the brakes are applied causing the car to pull one way or the other. Tires can also cause a pull that will change if the tires are swapped from side to side to change direction (rotation).
Check for Brake Hose Operation Blockage - Your car has flexible brake hoses that are reinforced rubber hydraulic pressure hoses. These hoses are needed to compensate the vehicles suspension travel. Solid metal brake lines will not bend with the suspension travel. (This travel will cause a solid metal brake line to fail) These brake hoses are capable of holding thousands of pounds of brake fluid pressure without failing. Because these hoses are made of rubber they can fail internally allowing a small part of the inner hose liner to become dislodged and act like a one way check valve that will either hold full brake pressure from getting a particular wheel or not allowing the brake pressure to bleed off.
This condition with cause the brake to not work as hard as the other wheels or cause the wheel to drag and not fully release. Either of these conditions will cause a brake pull condition. If you suspect this problem use a pocket IR thermometer laser temperature reader. Drive the car for a short distance with repeated braking then park the car and use the pocket IR thermometer to test each wheel. You must test each wheel in the exact same place (I like to use one lug nut on each wheel). You are monitoring temperature differences from side to side, not from front to rear. Front to rear temperature differences are normal, side to side is not. (both front or both rear wheels) If a measurable amount of temperature differences exists replace both brake hoses involved. (Note: most brake pull problems of this nature are front brake related). Example: if both front wheels are tested and the right temperature reading is 190 degrees and the left side is 80 degrees, there is a problem.
Pocket IR Thermometer Laser Temperature Reader
