Why does the Rear Suspension Squeak?

In this brief article, we will discuss rear suspension squeaking, the causes for rear suspension squeaking and steps to prevent it.

Why does the Rear Suspension Squeak?

Rear Suspension Squeak is caused by multiple factors depending on the particular type of rear suspension setup that your car or SUV has. The most probable sources of squeaking based on suspension type are:

Leaf Spring Rear Suspension

• Many Pickup trucks have a rear leaf spring suspension for heavy duty applications
• If there are multiple leafs like in the semi-elliptical type, then inter-leaf rubbing can cause squeaks
• Spring hanger Pins, in many vehicles, are of the serviceable type. Lack of proper greasing can cause squeaks and rattles.
• Spring hanger pins that have a rubber bushing can start to squeak when the rubber has disintegrated

Anti Roll Bar Linkages

• Most independent suspensions come with an anti roll bar. The anti-roll bar is mounted to the chassis or subframe through rubber bushings. 
• When there is a lack of lubrication at the Chassis mounting D-Bush, it could lead to squeaks.

Rear Multi-link Suspension

• Rear suspension control arms are sometimes attached to the chassis or subframe through conical rubber bushings that are compressed while torquing the joint. 
• Due to weathering, sometimes, the rubber could grip the metal portions and cause squeaking noises.

Shock Absorber Failure

• Shock Absorbers work based on their internal sealing action between the Rod, the Piston and the cylinder. The sealing effect is achieved by means of flexible sealing interface rings that are susceptible to wear in the long-term.
• A Failed shock absorber would have the internal piston rubbing against the cylinder when the seal has worn out completely. The  resulting metal-to metal rubbing leads to squeaking noises.

Rusted Parts

• In cases of extreme corrosion and rust, where the suspension arm or subframe has lost material to flaking, there is a high probability of squeaking.
• In the cases of extreme rust, it is mostly observed that the vehicle could be operating in the ‘Salt Belt’

How to prevent Suspension Squeaking Noises?

• It would be advisable to inspect all the rubber bushings in the suspension at the OEM recommended intervals and see if the rubber portion has any cracks or disintegration. Timely replacement of these parts could help prevent the occurance of squeaks
• One way to prevent squeaks is to ensure lubrication of all the serviceable ball-joints at regular intervals.
• In the case of sealed ball-joints, make sure to replace the joint whenever there is either a crack or tear observed anywhere on the protective rubber boot surrounding the ball-joint.
• In joints where the rubber bushing is compressed and tightened against the mating surfaces, make sure to use Anti-seize which is meant for rubber joints. Anti-roll bar mountings are also usually of this type and therefore require lubrication.
• In the case of semi-elliptic leaf spring suspensions where there is more than one leaf, the interleaf contact surfaces are either lubricated with silicone-based product or spaced with thin low-friction layer wear pads or both.

Can I drive with a squeaky suspension?

Yes, it is possible to drive with a ‘Squeaks’ in the suspension, in most situations. 

As a word of caution, it is always best to inspect the suspension before commencing driving. 

If the squeaking is due to some rubber bushings deteriorating, it is probably OK to drive till they can get sorted.

The only situation where it would be not advisable to drive, is where the squeaking is due to rusting of the suspension structure. When the squeaking is due to rust, it means that the structure has disintegrated and that it is only a matter of time before the suspension collapses completely.

Conclusion

In this brief article, we have discussed suspension squeaking, the causes for suspension squeaking and steps to prevent it.