What it Does
Suspension struts maintain stability of the vehicle’s body and help maintain tire contact with the road. They resist body sway and nose dive. They also do a lot to maintain ride quality by cushioning road surface impacts and vibration from road surface imperfections.
Why This Matters
Struts are an integral part of the vehicle’s suspension. They are crucial for a vehicle to be able to handle safely in demanding conditions. Struts in good condition help to control braking distance, and they resist excessive movement of the vehicle’s body, which helps to keep the suspension planted and the tires constantly in contact with the ground. It’s also nice to have good ride quality – especially if you spend a substantial amount of time in your vehicle, or carry passengers!
Possible Problems
Strut Failure (Externally Visible)
Leakage:
Externally visible leakage indicates that the strut’s hydraulic charge is leaking to the outside of the strut. Loss of too much hydraulic fluid will affect the strut’s ability to perform both in controlling the vehicle’s handling and cushioning against shocks and vibration.
Damage:
Vehicle on vehicle collisions and severe pothole, curb, or debris strikes can cause struts to bend. This can alter or destroy the ability of their internal valving to properly control strut operation and will also pull the vehicle out of alignment. In these conditions, the strut may even completely jam in extended or compressed positions.
Strut Failure (Internal)
Please note that internal failures will commonly show no external signs. Struts are internally valved to channel liquid and gas, and failure or degradation of these functions impact strut performance without showing externally. In some cases, excessive rebound may be found, and even this may not be observed until an extended drive heats the fluid charge inside of the strut. Stiff suspension springs can also mask excessive strut rebound under low speed or stopped conditions.
Jounce Bumper Failure
These bumpers are commonly installed on the strut rod and are prone to damage from wear and tear as well as environmental conditions.
Torn Debris Shields
If the strut is in good condition otherwise, in most cases, there’s no benefit to paying to have these shields replaced. Strut longevity may be reduced by debris getting into the shaft sealing area, and this will require strut replacement if the strut begins to fail. However, replacement of these shields requires removal and disassembly of the strut units anyway, so these shields don’t typically get replaced outside of major strut service. However, strut replacement should always include replacement of these shields, or re-use of shields in good condition.
Noise
Worn or destroyed spring insulators (or “cushions”) may allow rub, creak, or thump noises caused by metal on metal contact between the strut assembly and suspension spring.
Strut Mount or Bearing
Failure in this area can result in increased steering effort or separation of the top of the strut from the vehicle body.
Recommended Parts Brands
- Manufacturer Genuine/Factory Grade
- Bilstein
- Sachs