Common Reasons For Wheel Bearing Failure
When a bearing wears out, it is usually a case of inadequate lubrication, faulty installation or improper adjustment. For the repair to be successful, you must first determine why the previous bearing failed. For sealed hub units, examining the internal bearings and races is impossible.
Replacing Wheel Bearing Hubs Equipped With Wheel Speed Sensors
When engineers came up with the idea of putting the wheel speed sensor (WSS) and tone ring inside a sealed wheel bearing hub assembly, it seemed like a great idea. The sealed environment would help protect the sensor and make it less vulnerable to damage or contamination from the outside.
Impact Damage On Wheel Hubs
When a driver hits a pothole or curb hard enough, extreme forces are put onto the balls or rollers and races of the bearing. This can result in the formation of a very small mark on the surfaces. The driver might go 1,000 miles or more before these components start making noise.
Drive Shaft And Drivetrain Vibrations: Understanding The Order And Math
To determine if a vibration is vehicle- or engine-speed related, the easiest thing to do is slip the transmission into neutral and let the vehicle coast when the vibration is most noticeable. If the vibration continues, then the vibration is vehicle-speed related. Likewise, if the vibration subsides, the vibration is engine-speed related.
How Noise, Vibration And Harshness Driveline Diagnostics Is Changing
This article will introduce you to some of the basic terminology and testing techniques used in modern NVH diagnostics.
New Wheel Bearing Technology
For an engineer, wheel bearing design and selection can be a balancing act between durability, cost and fuel economy. A large bearing might be great for potholes and heavy loads. But, there is only so much room in the hub and knuckle. Also, the larger bearing might have increased rolling resistance due to a larger sealing surface.
Press Fit Bearings: Like Pulling Teeth
Removing a cartridge-style wheel bearing can be like pulling a tooth. Sometimes it comes out in one pull, but sometimes it requires emergency surgery. This can be a service opportunity for your shop, with a lot of import vehicles equipped with these bearings in the front and rear. While the fundamentals of the job have not changed since the 1980s, what has changed is the complexity of the knuckle and the bearing seals, as well as the materials from which the knuckles and axles are made.
Spring Is Pothole And Bearing Season
The classic symptom of a bad wheel bearing is typically a cyclic chirping, squealing or growling noise that changes in proportion to vehicle speed. The sound may only appear or disappear at certain speeds. The noise may get worse when turning, or it may disappear momentarily. So, it’s difficult to make a diagnosis based on noise alone.
Torque And Runout: Measure Twice, Install Once
There are two critical measurements when installing a modern hub unit or cartridge bearing: torque and runout in the flange. Ignoring these critical numbers to save time will only lead to more comebacks and angry customers.
Wheel Bearing Noise Diagnostics
The classic symptom of a bad wheel bearing is typically a cyclic chirping, squealing or growling noise that changes in proportion to vehicle speed. The sound may disappear at some speeds or only occur at certain speeds. The noise may get worse when turning, or it may disappear momentarily. So, it’s difficult to make a
