John Deere Cab Suspension Issues Explained

In this brief article we are going to discuss the different John Deere Cab Suspension problems, what the causes are, and Troubleshooting Tips.

What are the most Probable John Deere Cab suspension issues? 

The most “Probable” John Deere Cab suspension issues are:

• Hydraulic Fluid Leakage
• Strut Failure
• Power Unit Failure
• Control Arm Bushing failure

John Deere Cab Suspension

John Deere is one of the world’s most trusted brand in Agricultural equipment. In its current form John Deere has a very sophisticated system to isolate the driver from vibrations that come from field undulations

9RX Cab Suspension

A Classic example of one of John Deere’s Cab Suspension systems is the one used on the 9RX 4wd Track Tractor. The 9RX Cab Suspension has the following layout:

• 4 Spring Dampers at 4 corners
• A Lateral Torsion Bar
• 2 Parallel Control Arms in forward direction
• A Panhard Rod

• Since the tractor does not have suspension, it is required to have a 4 corner suspension in order to isolate the driver from the rough farm terrain. The Spring dampers have been tuned specifically for the 9RX alone in order to ensure maximum comfort 
• The Torsion Bar, much like an Anti-roll bar, resists the Cabin Roll motion. This is essential to minimize drive fatigue and roll vibrations induce the maximum discomfort
• The 2 parallel control arms guide the cab’s pitch motion and fore-aft longitudinal motion

• The rear Panhard Rod resists lateral movement of the Cab

5R Optional Cab Suspension

The 5R Optional Cab Suspension is a Passive Mechanical Spring-Damper system that is specially tuned for the 5R’s duty cycle.

6R/8R Semi-Active Cab suspension ‘HCS Plus’

Another fine example of an advanced Cab suspension is the John Deere 6R Cab suspension. The 6R has Semi-Active Hydraulic Cab Suspension, also known as ‘HCS-Plus’ 

Semi-Active Shock Absorbers react to Speed and Load changes, continuously changing the Damping as per the instantaneous requirement.

The HCS plus cabin suspension controller adjusts damping according to inputs from the TLS Plus Front suspension sensors in an active fashion.

Potential problems with John Deere Cab Suspensions

• There is not much reliable data available as to what are the actual failures in a John Deere Cab Suspension
• Judging from the component layout of the differend JD Cab suspension set up, the following problems will potentially arise:

Hydraulic Fluid leakage

• This is applicable to the 6R/8R hydraulic cab suspension systems.
• The Hydraulic actuators need to operate at a moderate pressure
• Hence, all the hydraulic lines and connector fittings at the Reservoir, and the Struts could be potential weak spots for leakages

Strut Failure

• This is applicable to the 5R/9RX Mechanical cab suspension systems
• The suspension struts work like any Automotive suspension Coilover and tend to fail in a very similar way
• The Coilover Strut’s durability lies in its ability to seal.
• The potential weakest points in the Cab struts, that are likely to leak, would be the Top Rod seal and the internal Piston seal
• Once any of the damper seals fail, the strut has basically lost its ability to dampen vibration.

Power Unit Failure

• As seen with other advanced electronic automotive suspension control systems, the Power Unit is a potential failure point
• Electrical connectivity issues, have been observed in almost every car model that had Electronic Suspension Control
• Being a complex system, the ECU within the Power Unit could fail in countless ways

Cab suspension Bushing failure

• The Control arms and Torsion bars are connected via bushings
• The primary role of these bars is to restrain and guide the motion of the cab
• If these rod bushings wear out, the cabin movement becomes excessive and eventually leads to a highly uncomfortable and harsh ride experience for the Driver

Conclusion

In this brief article we have discussed the different Ford Expedition Suspension problems, what the causes are, and Troubleshooting Tips.

For any questions or comments, please feel free to get in touch with us.

References