Can you drive a car with Suspension Problems?

In this brief article, we are going to discuss how suspension problems affect the driveability of a car and the impact of suspension problems on the safety of cars.

Is it advisable to drive a car with Suspension Problems?

The answer would be Yes AND No. 

Yes, you can drive a car that has minor suspension issues like,

• Bushing failure
• Shock absorber failure
• Wheel bearing failure
• Ball-Joint failure
• Minor leakage in the Air Suspension system

.. but, ONLY, as long as you don’t intend to drive anywhere near the upper limits of highway speeds.

No, you MUST NOT drive a car that has major suspension issues like,

• Leaf Spring / Coil Spring breakage
• Control Arm Breakage or detachment
• Complete failure of the Air Suspension System

Bushing failure

• Bushings are present in most suspension linkages or “Arms”. They connect:
  • One linkage to the other, and
  • The linkage to the Chassis
• Bushings, in a majority of cases are made of Rubber and provide flexibility of movement within a controlled range.
• Once the Rubber portion of the bushing damages, the linkages move excessively and cause problems in wheel alignment and noise
• The suspension still would work, but safe only to a certain speed. The handling behaviour of the vehicle is greatly affected by damaged bushes and excessive deviation in wheel alignment.
• The allowable speed with damaged suspension bushings is highly subjective to the how bad the damage is, and what is the is the level of driving skill that the driver/owner of the car possesses.

Shock absorber failure

• Shock absorber or Damper is the device that absorbs the majority of the vibrational energy coming from road through the suspension. 
• One more function of the shock absorber is to control the handling behaviour during cornering at high speeds.
• A failed shock absorber means more vibration and shocks experienced in the car body structure, or in short, moer “Springiness”.
• Failed shock absorbers means a more bouncy feeling inside the cabin
• With respect to handling behaviour, a failed shock absorber could result in excessive vehicle roll and a less stable feeling at high speeds.
• To sum up, a failed shock absorber is acceptable, only as long as the driving speeds are low to moderate.

Wheel bearing failure

• Wheel bearing failure is characterized by droning noise, which happens at speeds above 30 mph
• Bearing failures generally do not cause a great amount of deterioration in  the function of the vehicle
• But, however, like most other suspension issues, if bearing failures are left unattended, these failures could lead to wheel lock-up in the most extreme of possibilities.

Ball-Joint failure

• Ball-joints provide pivots between suspension arms and the wheel knuckle
• A worn-out ball-joint leads to play between the 2 components that the ball-joint connects
• The most commonly used suspension ball-joint is the Control Arm ball joint. The location of the control arm ball joint with respect to the chassis will determine the Camber and Scrub-radius and King-pin offset in the suspension
• A change in Camber and Scrub-radius, due to play in the ball-joints, will adversely affect the handling characteristics of the vehicle.
• The steering basically will feel vague and the car would seem a bit more difficult to control.
• Therefore high speed manuevering would be challenging in such situations.
• Apart from affecting handling characteristics, the ball-joints also take up some part of the road vibrations coming from the terrain.
• Failed ball-joints also lead to knocking noises while going over bumps and bumpy roads

Minor leakage in the Air Suspension system

• If your car hap[ens to have air suspension instead of conventional springs, the springs would be rubber bellows that are pressurized to maintain ride height as well as spring rate
• The air spring bellows would last only upto, say 70-80K miles, under normal usage conditions. Beyond that point, the air bellows would most probably start to develop cracks and leakages
• Such leakages would lead to loss of air pressure, especially when the car is parked for long periods of time.
• In more severe cases, loss of air pressure happens during normal driving
• The loss of air pressure is usually compensated by an air compressor when the system detects that the air pressure is inadequate.
• The air compressor is limited by its working temperature and cuts out when it is overworked.
• In these situations, the loss of air pressure is not compensated by the compressor and the vehicle sits lower than the required ride height
• With air springs that are not adequately pressurized, there is effectively very weak springs and limited suspension effect.
• Most vehicles control systems display a warning to drive slowly, or in some cases, even forcibly switch the car to limp mode to limit driving speed.

Leaf Spring / Coil Spring breakage

• Depending on the usage environment of the vehicle, Coil springs and leafsprings do tend to corrode over time and gradually develop cracks
• Also due to age and fatigue, over time, steel springs develop cracks
• Once they develop cracks, it is only a matter of time before the springs get broken in two
• Once a breakage happens, the suspension collapses and the affected corner rides low.
• A broken spring is basically ‘No Spring’ and hence potentially dangerous situation since there is no means to maintain contact between the road and tire.
• It would basically be dangerous to drive the vehicle under such circumstances

Control Arm Breakage or detachment

• Control arms guide the wheels and provide a defined path for the wheels to move upwards and downwards as per road terrain
• Once there is breakage in a control arm, there is no longer control over the suspension movement, and the wheel would basically move unpredictably
• This is a dangerous situation since it would not be possible to steer or control the vehicle

Complete failure of the Air Suspension System

• A complete failure of the Air suspension would mean total loss in air pressure
• Complete loss of pressure implies that the air springs have completely collapsed
• A collapsed air spring is a potentially dangerous situation since there is no means to maintain contact between the road and tire.
• It would basically be dangerous to drive the vehicle under such circumstances.

Conclusion

In this brief article, we have discussed the different Range Rover Evoque suspension issues, what the causes are, and how these issues can be effectively dealt with.

References

• https://static.nhtsa.gov/odi/tsbs/2019/MC-10161419-9999.pdf