Wheel Bearing Service Tips
rvice could come back in fashion on vehicles instead of just on boat trailers. Since serviceable wheel bearings are rare, they often fall victim to wives tales and urban legends. One of the most prevalent is the myth of spinning a bearing with compressed air. Proper service required the bearing cage and roller assembly not
Oxygen Sensors: Pulse Measurement
Watching an oxygen sensor output on an oscilloscope is like watching a sporting event on television. You get to see the action, but can do nothing about it as it happens. Sometimes you miss the action and want an instant replay. It was a bad call. You saw the interference. If the referee didn’t see
Automatic Transmissions: From Mechanical to Electronic to Hybrid
A long time ago in a service bay, preventive maintenance for an automatic transmission was an oil change, band and throttle linkage adjustment. The 1960s saw the end of external band adjustments. In the 1970s, the drain plug went away and the pick up screen was replaced with a filter. In the 1980s, a turbo
GM ‘W Platform’
Preventive Maintenance and Undercar Service
Selling Services: Brake Line Repair: Tubing, Hoses and Fluid
Corroded brake lines and flare nuts have been a problem since hydraulic brakes were first installed on vehicles. Improved materials and processes have improved serviceability, but in the Northeast and Midwest where salt and other agents are used to de-ice roads, it is still a problem. Brake Tubing 101 Beginning in the 1930s, the Bundy
When Should You Replace an Oxygen Sensor?
Is there a mileage or time requirement for oxygen sensor replacement? Simple answer: No. Oxygen sensors were first used for fuel trim and emissions in the late 1970s and into the mid 1990s. A single sensor was installed into the exhaust stream to modify fuel delivery and maintain catalytic converter efficiency. Beginning January 1, 1996,
Electric Power Steering
When a technology like hydraulic power steering has been around for so long, it is difficult for technicians and even the training establishment to deal with a new system like electric power steering. These systems abandon fluid logic for electronic logic. It is not a simple exchange of power steering fluid for magnetism. Wrapping one’s
Rotor Runout: Cause and Correction
The vehicle owner may say that under light braking the vehicle pulses to a stop or under heavy braking the vehicle shudders. Technical service bulletins (TSBs) often describe these symptoms as a “judder.” There are only two causes for judder — lateral runout and disc thickness variation on the rotor’s friction surface. What could have
Drum Brake Self Adjusters: Understanding These Ancient Devices
d bridge bolts. Opposing piston calipers are bolted to the knuckle and have pins to position the pads. Drum brakes have return springs to return the shoes to a rest position and hardware to hold the shoes to the backing plate. The shoes return to a fully retracted or rest position when the master cylinder
A Brief History of the Steering Wheel & Power Steering
It’s 1956 and the 20-inch-diameter steering wheel on a Chevrolet Bel Air or Ford Fairlane provided the leverage to steer the wheels. But, it was especially difficult to turn the steering wheel when the vehicle was stopped. Turning the wheel required a certain amount of upper body strength that was given by God to truck
Wheel, Rotor and Drum Removal
The traffic whizzed by at seventy plus. The good news: The flat is on the rear passenger side and the lug nuts came off with little strain. The bad news: The alloy wheel is seized on the hub and it isn’t going anywhere. Twist of fate: I forgot to chock the front wheel and the
Tie Rod Geometry
Keeping the angles in line with Ackermann Most people consider the common tire rod to be low tech. But, when you consider how front suspensions have evolved from straight axles to independent designs, the tie rod has had to adapt to new angles and geometry. Keeping it on the road was simple with the straight