In this brief article we are going to discuss the different Subaru Outback Rear Suspension issues, what the causes are, and how these issues can be effectively dealt with.
What are the common suspension issues in the Subaru Outback?
The most common Subaru Outback suspension issues that occur are failures in the following parts:
- Rear Spring Breakage
- Rear Shock-absorbers
- Rear Upper/Lower Control arm bush failure
- Rear anti-roll bar recall
- Rear Anti-roll bar Bush failure
What suspension does the Subaru Outback have?
The Subaru Outback’s, which was also sold as the Subaru Legacy Outback, was launched in 1994. The Outback is currently in its 6th generation.
The front suspension is a conventional MacPherson Strut set-up with Anti-roll bar
The Rear Suspension of the Subaru Outback is of independent 4 – link type, consisting of a Trailing arm, Upper Link, Lower Link and Toe Link
Front Lower Control Arm Failure
- The car seems to be drifting
- Steering seems vague while Lane Changing
- Uneven Tire Wear pattern
- Knocking Noises while going over Rough Patches
- Usually seen in ‘05 – ‘09 Subaru Outback Model years
- Due to a Tire wear issue, it can be inferred that the alignment of the front suspension is outside of the recommended settings. But this is still a symptom.
- The cause for the change in alignment is closely related to the Lower control arm Bushings and Ball-joints that may have got worn or damaged
- With worn out bushings and ball-joints, when the tires experience lateral contact forces from the road, the play caused by worn out bushes/ball-joints allows the suspension to move out of its alignment and cause premature tire wear.
Troubleshooting Front Lower Control Arm Bushing Failure: Lower Control Arm Bushing
- Lower Control Arm bushing wears out over time and cracks due to age
- To assess the bushing condition, you can use a Pry-bar and insert it between the Lower control arm and the Subframe.
- Now, try to move the Lower Control arm using the Pry-bar and observe the movement at the Bush location. If the lower control arm moves without much force, then it means that the bushes have worn out.
- When inspecting the Lower control arm after removal, it is clear that there are tears and cracks in the rubber portion.
Troubleshooting Front Lower Control Arm Bushing Failure: Lower Control Arm Ball-Joint
- The lower control arm ball-joints are also subject to wear and tear.
- The deterioration is usually initiated as a crack or rupture in the rubber boot around the ball-joint
- This leads to loss of lubrication and finally to complete wear out
- The wear out causes play or movement accompanied by knocking noise. The play in the ball-joint is one of the reasons for the vehicle steering feeling value
- You can easily check for Ball-joint condition by this simple procedure:
- Get the car on a Ramp
- Lock the steering wheel
- Hold the front tire with both your hands and try to steer the wheel
- If you hear a ‘Knock’ or ‘Click’, then it is very much likely that the noise is due to a play in the Ball-joint
- The best course of action would be to replace the whole Lower control arm since it comes with 2 new bushings and 1 new ball-joint all pre-assembled
Rear Shock Absorber Strut Failure
- Rear Knocking and Squeaking noise
- Rear end feels bouncier
- Noise is louder going over rough surfaces
- Knocking and Squeaking noises could be due to multiple reasons.
- One way to diagnose a ‘Squeak’ is to simulate the suspension movement in this way:
- Jack the rear and support it on Jack-stands
- Place a jack underneath the rear wheel-hub and jack it in order to imitate suspension movement
- Closely observe the source of the noise and then accordingly dismantle the related components
- The Rear Strut mount is a known potential failure point. The Top mount has a rubber support which is prone to failure and noise.
- The next probable cause is the shock absorber or damper within the rear Strut assembly. A failed damper causes a bumpy ride as well as noise.
Troubleshooting Rear Shock Absorber Strut Failure: Strut Top Mount
- The Upper Strut Mounting bolts are accessible only from inside the vehicle
Troubleshooting Rear Shock Absorber Strut Failure: Shock Absorber
- The Bouncy Ride symptom points to the Shock Absorber as a probable cause.
- The noises coming from the rear are partly due to the failed shock absorber allowing the bump stops to contact more often. And also the noises partly come from the worn out shock mounting bushes that allow the shock to move and hit against the mounting brackets.
- If your vehicle has crossed 60K miles, then it could be due for a shock replacement. Due to long-term internal wear, the shock starts losing its damping action over time.
- If the rear shock has started leaking oil due to a failed oil-seal, then it means that the shock will no longer be effective.
- One good way to tell if your shock has failed or not is to do a “Bounce Test”. Put all your weight on one of the front corners of the vehicle pushing it downwards. Keep oscillating the corner till you feel that it has reached its maximum height. Once you take your hands off the corner, observe how it settles. If it takes more than 2 oscillations to settle, that means the damper has failed.
- While dismantling the rear coil-over, it would be safest to use a Spring compressor and restrict the spring from expanding before removing the bottom mounting bolt. Otherwise you could risk the spring popping out and potentially causing injury to people in the vicinity.
- Screw compressors need to have proper hooks that don’t slip out while tightening. The spring could potentially open if the compressor hooks are not gripping properly.
- In the interest of safety, it is best to use the compressor tool recommended by your Subaru’s service instruction.
- As an additionally safety precaution you could also cable-tie the springs to the hooks
- While fitting a new shock absorber, always, Tighten the Top mounting bolts first and then the Lower mounting bolt.
- Also make sure that while tightening the Shock bottom bolt, the Wheel Hub is supported at its normal ride height. For this you can either use Blocks, a screwjack or a jack stand and raise/lower the ride height accordingly.
- If the shock bottom mounting bush is tightened at any other ride height, then when the car is lowered to normal ride height, the Bush will rest in a twisted condition and will have a reduced Bush service life.
Rear Upper/Lower Control arm bush failure
- The car seems to roll more
- Poor handling while Lane Changing
- Uneven Tire Wear pattern
- Knocking Noises while going over Rough Patches
- Normally seen in the 2007-08 Model years
- Due to a Tire wear issue, it can be inferred that the alignment of the rear suspension is outside of the recommended settings. But this is still a symptom.
- The cause for alignment change points to the Rear suspension Control arm Bushings that may have got worn or damaged
Troubleshooting Rear Trailing Arm Bush Failure
- The Rear Upper/Lower Control Arm bushings wear out over time and crack due to age
- To assess the bushing condition, you can use a Pry-bar and insert it between the Each of the Rear suspension control arms and the rear Subframe. Now, try to move each Control arm using the Pry-bar and observe the movement at the Bush location. If the control arm moves without much force, then it means that the bushes have worn out.
- When inspecting the Control arms after removal, you can assess the exact condition of the bushing by looking for tears and cracks in the rubber portion.
Anti Roll Bar Drop Link Failure
- ‘Clunking’ Noise while driving
- Noise is very less on a smooth road and more apparent when driving over a rough patch
- This failure is seen in the ‘05-’09 model year suspension
Troubleshooting Anti Roll Bar Drop Link Failure
- Rear Knocking sounds that increase on a rough road are the signs that point to an issue with the Anti-roll bar(ARB) links
- The anti roll bar does not articulate so much on smoother surfaces and hence is less noisy
- An easy way to check the ARB linkages is to hold each link and shake it by hand observing for movement or noise at each linkage point.
- The perfect way would be to remove the ARB Drop Links and check the ball-joint for excess play
In this brief article we have discussed the different Subaru Outback Suspension issues, what the causes are, and how these issues could be effectively dealt with.
For any questions or comments, please feel free to get in touch with us.