Plastic suspension components are common in many modern vehicles, prized for their lightweight and cost-effective design. But if you notice a plastic part of the suspension is cracking, it can lead to safety concerns and performance issues. This article explains why these parts crack, how to inspect them, and what to do about it—including when to replace and how to choose the right parts.
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Energy Suspension 9.8103R Sway Bar End Bushing
Common Plastic Suspension Components
Plastic parts are used in several suspension areas. Knowing which ones are prone to cracking helps you identify problems early.
Control Arms
Some lower control arms have plastic bushings or brackets. While the arm itself is often metal, the plastic bushing housing can crack under stress.
Strut Mounts
Strut mounts frequently use plastic top plates or bearing housings. Cracks here can cause clunking noises and affect steering response.
Sway Bar Links
Many sway bar links (end links) have plastic ball joints or sleeves. Cracking in these parts leads to loose sway bar connection and body roll.
Spring Seats
Rubber or plastic spring seats can crack over time, causing noise and misalignment of the coil spring.
Why Plastic Suspension Parts Crack
Several factors contribute to cracking. Understanding the root cause helps you prevent future failures.
Age and Exposure
Plastic degrades with UV light, heat, and cold cycles. Over years, this weakens the material, making it brittle and prone to cracking.
Road Conditions
Potholes, curbs, and rough roads subject suspension parts to sudden impacts. Plastic components are less forgiving than metal and can crack under these loads.
Manufacturing Defects
Occasionally, parts have molding flaws, air pockets, or thin sections that crack prematurely. This is more common in cheap aftermarket parts.
Overtightening
When installing parts, over-torquing bolts that go through plastic can create stress cracks around the hole.
How to Inspect for Cracks
Regular inspection catches cracks before they become dangerous. Here’s a simple check you can do.
Visual Inspection
Jack up the car and support it on stands. Look at all plastic parts for hairline cracks, chips, or white stress marks. Use a flashlight and probe with a screwdriver (gently) to see if cracks open.
Listen for Noises
Cracked plastic often creates clunks, squeaks, or rattles over bumps. Note where the sound comes from—this pinpoints the affected component.
Check for Play
Grasp the part and try to move it. If there is abnormal movement or if a plastic bushing looks separated, the part is likely cracked or worn.
Repair vs. Replacement
Can you repair a cracked plastic suspension part? In most cases, no. Here’s why replacement is usually the only safe option.
When to Replace
Any crack that compromises structural integrity requires replacement. Do not attempt to glue or weld plastic suspension parts—they will fail under load. Replace immediately if you see cracks larger than a hairline or if the part is broken.
Cost of Replacement
Costs vary by vehicle and part. A sway bar link might cost $15–$50 for aftermarket, while a control arm assembly can be $100–$300. Labor adds $50–$150 per part if you hire a shop. DIY replacement is often straightforward with basic tools.
Choosing Replacement Parts
When replacing cracked plastic suspension parts, you have options. Choose wisely to avoid repeat failures.
OEM vs. Aftermarket
OEM parts match original specifications and material quality. They are more reliable but cost more. Aftermarket parts can be cheaper but vary widely in quality. Look for brands with good reputation and warranties.
Material Considerations
Some aftermarket manufacturers offer metal replacement parts for common plastic failure points. For example, metal sway bar links or control arm bushings can last longer. However, they may transfer more vibration. Balance durability with comfort.
Fitment and Compatibility
Always check parts against your vehicle’s year, make, and model. Use online fitment tools or consult a parts store. Incorrect parts can cause improper alignment or early failure.
Final Recommendation
If you discover a plastic suspension part is cracking, do not ignore it. Inspect thoroughly, plan for replacement, and choose parts that match or exceed original quality. For critical components like control arms, consider upgrading to metal-reinforced versions. If you’re not comfortable with DIY, have a mechanic do the work. Regular inspections every 30,000 miles can catch cracks early and keep your suspension safe and reliable.