Whats Inside a Power Steering Rack?

Key Concepts:

• Power Steering Rack: A component in vehicles that assists the driver in steering by using hydraulic pressure.
• Pinion Gear: A small gear that meshes with the rack in a rack and pinion steering system.
• Valving Assembly: A system of valves within the power steering rack that controls the flow of hydraulic fluid to provide steering assist.
• O-rings: Circular seals used to prevent leaks in hydraulic systems.
• Metering Orifice: A small opening that controls the flow rate of fluid.
• Rack: A linear gear that meshes with the pinion gear in a rack and pinion steering system.
• Coil Bearing: A type of bearing used to support rotating shafts.

Disassembly and Inspection of a 2012 Honda Odyssey Power Steering Rack

1. Introduction

• Eric the Car Guy replaced the power steering rack on his 2012 Honda Odyssey due to a rattle/vibration in the steering wheel when going over bumps.
• The original rack is being disassembled to identify the cause of the issue and to showcase the internal components of a power steering rack.

2. Initial Observations

• The rack had external oil leaks, which was another reason for replacement.
• Suspected damage to the pinion gear/rack interface due to a prior collision.

3. Removal of External Components

• Hard Lines: Removed using a 14mm line wrench. These lines connect to the valving assembly.
  • O-rings were present on the hard line fittings, indicating they should be snug, not overly tightened.
• Fittings/Valves: Removed from the valving assembly.
  • These fittings contained springs, valves, and metering orifices to control fluid flow.
  • One fitting had a spring and a valve, while another had only an orifice.

4. Valving Assembly

• The valving assembly is held in place by two 12mm bolts.
• The assembly contains a bearing and passages for power steering fluid to flow through the hard lines.
• The assembly directs high-pressure fluid in and low-pressure fluid out to assist with steering.

5. Pinion Adjustment Mechanism

• The mechanism allows for adjusting the clearance between the pinion and the rack.
• A lock nut and a 3/8" plug are removed to access the spring-loaded tensioning device.
• The tensioning device applies pressure to the back of the rack.
• Turning the steering wheel causes the pinion to move the rack left and right.

6. Pinion Shaft Removal

• A 15/16" cap and a 17mm nut are removed to access the pinion shaft.
• The pinion shaft is extracted, revealing a seal and a support bearing.
• The teeth on the pinion shaft are inspected for damage, but none is immediately apparent.

7. Rack Removal

• A special tool or screwdriver is used to rotate and remove a locking mechanism that secures the rack.
• A magnet is used to remove an end cap.
• Metal bits were found on the seal, indicating internal wear or damage.
• The rack is cleaned and inspected, but no obvious damage is found.
• The rack has holes that equalize pressure from one side to the other through the center of the shaft.

8. Valve Assembly Removal

• A snap ring is removed to detach the valve assembly.
• The valve assembly contains seals and passages for directing fluid flow.

9. Bearing Inspection and Identification of the Culprit

• The bearings within the valve assembly are inspected.
• One of the coil bearings (marked "One zero zero nine") is found to be stiff, notchy, and rough, suggesting it was the source of the rattle/vibration.
• The leakage in the area also suggests something was loose, preventing the seals from working correctly.

10. Conclusion

• While no major damage was found on the rack or pinion, a faulty coil bearing in the valve assembly is identified as the likely cause of the steering wheel rattle.
• The video provides a detailed look inside a power steering rack, showcasing its components and how they function.
• The presenter encourages viewers to use the video as a guide for rebuilding their own power steering racks.
• Links to related videos and resources are provided in the description.