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Machine Background and Problem Description
The Bobcat 873 skid steer loader is well-regarded for its robust design and versatility in landscaping, construction, and material handling. However, its foot pedals, which control lift and tilt functions through hydraulic linkages to the hydraulic control block, occasionally experience mechanical sticking or jamming.
An operator reported a situation where, after forcefully pressing the lift foot pedal to prevent an overhead hazard, the pedal became stuck firmly in the down position. Despite attempts to pry the linkage near the hydraulic block, there was no movement, although linkages appeared undamaged and without obstructions. This stuck pedal prevents return to neutral, disabling safe operation.
Potential Causes
A stuck foot pedal on a Bobcat 873, especially one that controls lift functions, is likely caused by a seized hydraulic control block, residual pressure, or linkage binding. Careful inspection, cleaning, lubrication, and pressure release form the first steps toward resolution. Preventive upkeep and cautious pedal actuation can avoid recurrence, safeguarding operator safety and machine functionality.
The Bobcat 873 skid steer loader is well-regarded for its robust design and versatility in landscaping, construction, and material handling. However, its foot pedals, which control lift and tilt functions through hydraulic linkages to the hydraulic control block, occasionally experience mechanical sticking or jamming.
An operator reported a situation where, after forcefully pressing the lift foot pedal to prevent an overhead hazard, the pedal became stuck firmly in the down position. Despite attempts to pry the linkage near the hydraulic block, there was no movement, although linkages appeared undamaged and without obstructions. This stuck pedal prevents return to neutral, disabling safe operation.
Potential Causes
- Hydraulic Control Block Jamming: Components inside the hydraulic control block that receive pedal input (such as spool valves or actuators) may seize or bind due to contamination, corrosion, or lack of lubrication.
- Mechanical Linkage Binding: Although linkages may appear intact, small misalignments or bent pins can cause binding.
- Safety Lockouts: Sometimes a safety bar or lockout mechanism may interfere with pedal return if malfunctioning or incorrectly engaged.
- Hydraulic Pressure Lock: Residual hydraulic pressure in circuits can cause the pedal or related components to resist movement.
- Wear or Damage on Pivot Points: Worn bearings or bushings on pedal pivot assemblies can cause pedal hang-up.
- Inspect and clean the hydraulic control block area thoroughly to remove dirt, debris, or corrosion.
- Check pivot points, pins, and bushings on the pedal linkage for wear and replace as needed.
- Test for residual hydraulic pressure holding the system; relieve pressure by manually cycling auxiliary circuits or following manufacturer depressurizing procedures.
- Lubricate all linkage and pivot parts generously with appropriate grease.
- Release safety lockout bars fully and inspect switch mechanisms for proper function.
- If jamming persists, consider hydraulic control block disassembly and inspection for internal valve seizure or debris presence.
- Use penetrating oil on linkage joints to aid freeing stuck parts.
- If the pedal assembly or hydraulic valves are faulty, replace components using OEM parts.
- Avoid sudden heavy force on pedals; gentle, steady pressure minimizes risk of mechanical damage.
- Regular maintenance and cleaning of pedals and hydraulic control valves prevent seizing problems.
- Always ensure safety interlocks and lockouts function correctly before operation.
- Temporarily immobilized pedals can pose significant safety risks, so address immediately.
- Hydraulic Control Block: Assembly of valves and actuators controlling fluid flow to hydraulic cylinders.
- Spool Valve: Valve inside hydraulic control block directing flow based on control inputs.
- Lockout Bar: Safety feature preventing unintended hydraulic activation.
- Pivot Pin: Hinge or axle on which pedals or levers rotate.
- Penetrating Oil: Lubricant designed to loosen rusted or stuck mechanical parts.
A stuck foot pedal on a Bobcat 873, especially one that controls lift functions, is likely caused by a seized hydraulic control block, residual pressure, or linkage binding. Careful inspection, cleaning, lubrication, and pressure release form the first steps toward resolution. Preventive upkeep and cautious pedal actuation can avoid recurrence, safeguarding operator safety and machine functionality.
