January 25, 2021 by Jake Schell
Potential Hydraulic Brake Issues
Let’s look at three potential concerns that may affect the braking system on medium duty trucks equipped with hydraulic brakes.
Most truck drivers know that there is a difference in pedal feel between air brakes and hydraulic brakes. However, with the advent of antilock brakes on vehicles with hydraulic brake systems, the pedal pressure is a little trickier than in the past. With pre- or early antilock brakes, when pushing the brake pedal to the floor, pressure could be clearly felt in the pedal and the wheels would begin their “dance” as the brakes were applied and released to prevent a skid.
As brakes became more powerful and efficient, less effort is now needed to slow and stop the vehicle. Consequently, drivers may end up applying too much brake pedal pressure in an effort to slow the truck and cause an antilock stop. Such stops, in turn, result in faster wear of the brake lining. Thus, when inspecting brakes, it’s recommended to use a scan tool to determine the number of antilock stops and if excessive, explain proper operation to the driver.
Next, wheel ends also play an important role in proper brake operation and wear. When inspecting the wear patterns on brake shoes or pads, note any irregularities in wear from side to side as well as brake lining worn at an angle on a particular wheel. Loose or damaged wheel bearings may allow the linings to contact the drum or rotor at an angle causing increased wear on one side of the lining contact surface. Inspect the wheel bearings for wear or improper adjustment and correct as needed.
In the process of inspecting or replacing brake linings or pads, the connecting hardware and hydraulic cylinders may get overlooked. Any area in the brake with moving parts will wear, corrode, or just break. Whenever brakes are disassembled for repair, make sure to inspect springs, adjusters, cylinders, backing plates, and other hardware for wear or damage. When any of these components are not up to standard, poor performance and uneven wear will likely take place.
Want more? Here’s how you can get a free 14 day trial of TruckSeries:
Jake Schell is the Associate Product Manager for Mitchell 1’s commercial vehicle product line. He has been with Mitchell 1 since 2001. Prior to coming to Mitchell 1, Jake spent 20 years as a technician, with Chevrolet Master certification in the transmission category as well as ASE certifications in both car and truck.
2022 Owned and Managed by John Lopez - Mitchell 1 Independent Sales Representative - (504) 289-0953 - john.lopez@mitchell1repair.com