Control arms and trailing arms connect your wheels to the car body. They let the wheels move up and down while staying in line. When the rubber bushes or ball joints wear out, you hear clunks and the car feels loose.
Buying a used genuine OEM part can save you a lot of money. But you must match the OEM code exactly. That is the only way to know the part fits your car.
What Control Arms and Trailing Arms Do
Think of your suspension like a human leg. The control arm works like a hip joint. It pivots so the wheel can rise and fall over bumps.
A trailing arm is a longer arm that runs front to back. It is common on the rear suspension of many cars. It holds the wheel in place while the car moves.
Both parts use rubber bushings and sometimes ball joints. Rubber gets old and cracks. Once that happens, the arm moves too much and your tyres wear unevenly.
Common signs of wear
- Clunking or knocking sounds over bumps
- Vague or wandering steering feel
- Uneven or fast tyre wear
- Visible cracks in the rubber bushings
- Car pulls to one side when braking
Why genuine OEM matters
Genuine OEM means the part made by the company that built your car, or their approved supplier. Aftermarket parts can be fine, but fit and quality vary a lot between brands.
Used genuine OEM arms keep the original geometry and bushing stiffness. That means the car handles the way it did when new. You can read more about the engineering behind suspension design on Wikipedia's control arm page.
What an OEM Code Actually Is
An OEM code is the car maker's own part number. It is not random. Each number points to one exact part for one or more models.
You find these numbers stamped, laser etched, or on a sticker on the part. Sometimes the number is on a small metal tag. It may also appear on a plastic cap.
Here is the key point. Two control arms can look almost the same but have different codes. A small change in bushing size or arm length changes the number. If you fit the wrong one, the car may not align properly.
Where to find your code
- Look on the old part before you remove it
- Check the dealer parts diagram by VIN (Vehicle Identification Number, your car's unique ID)
- Ask a parts seller to confirm using your VIN
- Search the code on a parts database to see the fitment list
Example codes worth knowing
Some arms are shared across many models and are easy to find used. For example, a control arm with OEM 504207328 fits several vehicles from one large brand group. You can see the full fitment list on the control/trailing arm, wheel suspension, OEM 504207328 page.
Another common one is a kit form used on many Asian cars. Search control/trailing arm kit, wheel suspension, OEM 54506b9500 to see which models share it.
Bushings and mounts also carry their own codes. A small mount can cost very little used but save a lot of labour later. Check mounting, control/trailing arm, OEM 51391tr0305 for its fitment list.
Why OEM Codes Beat Guesswork
Many sellers list parts by make and model only. That is a problem. A 2015 model can have two different suspension setups depending on engine, trim, or market.
One car may use a steel arm, another an aluminium one. Sport versions often use stiffer bushings with a different code. The wrong arm can fit the bolt holes but ruin your alignment.
Matching by OEM code removes the guesswork. The code is the single source of truth. If the code matches your car's required code, the part belongs there.
OEM vs aftermarket: a quick compare
- Fit: OEM is designed for your exact car; aftermarket often fits a range
- Quality: OEM meets the maker's durability tests; aftermarket varies by brand
- Price new: OEM costs more; aftermarket is cheaper
- Price used: genuine used OEM can cost less than a new aftermarket part
- Resale: original parts are often a selling point
Good aftermarket brands like Bosch make solid parts too. But for a used part, genuine OEM is the safest bet because the code is verifiable.
How to Check Fitment Step by Step
Fitment means the part will bolt on and work correctly. Do this before you pay.
- Write down your car's VIN and exact model year.
- Find the required OEM code for your car's suspension arm.
- Read the part listing and confirm the same code.
- Check the fitment list to see if your model is included.
- Ask for clear photos of the stamped code.
- Confirm left or right side, and whether it is front or rear.
Left and right arms often have different codes and are not interchangeable. Always check the side before ordering.
Use your VIN
Your VIN tells a seller exactly how your car was built. Give it when you request a part so the team can confirm the right code for your car.
Buying a Used Control Arm Safely
A used arm can be a great deal if it is in good shape. The metal usually lasts the life of the car. It is the rubber bushings and ball joints that wear.
Ask the seller for the mileage of the donor car. Lower mileage is better. Ask if the bushings are intact with no cracks or play.
What to inspect when it arrives
- Stamped OEM code matches your order
- No cracks or tears in the rubber
- Ball joint moves smoothly with no rattle
- No bends, deep rust, or crash damage
- Threads and bolt holes are clean
When to replace the bushings
If the arm is good but the bushings are tired, you can press in new ones. This is cheaper than a new arm. But you need a press and the right bushing code.
Sometimes it is easier and not much pricier to buy a complete used arm with good bushings already fitted. You can compare options at browse parts by brand and pick the best value for your car.
Sourcing Used Genuine OEM Parts from Europe
Europe has thousands of professional dismantlers. They break cars that are no longer economical to repair, then test and store the parts.
Because so many cars share platforms and codes, a part that is rare in your country may be common in Europe. This is why sourcing across borders makes sense.
You do not need to contact yards yourself. A service like how Auto128 works finds the part by code, checks it, and ships it to you with tracking and customs handled.
Why used is good for the planet
Reusing a part keeps it out of the scrap heap and saves the energy of making a new one. The European Commission notes that reuse of parts is a key part of end-of-life vehicle recycling.
Shipping, Customs, and Costs
Cross-border shipping is simple if the seller handles export papers. A control arm is not heavy, usually between 2 and 6 kg. Shipping is affordable.
Customs duties and taxes depend on your country and the part's value. Some countries charge import VAT on used car parts. Others have a small threshold below which nothing is due.
What to expect
- Tracked delivery with a courier
- Export documents prepared by the seller
- Customs fees paid by you, the buyer
- Delivery in days to a few weeks, depending on distance
Ask for a landed cost estimate before ordering. That is the total price including shipping and any fees. It avoids surprises at your door.
Fitting the Arm Correctly
Replacing a control arm is a job a careful DIY mechanic can do with hand tools and a jack. But you need to torque bolts to the maker's spec and load the suspension before tightening rubber bushes.
If you tighten bushes with the car in the air, they twist and fail early. Lower the car onto its wheels first, or support the hub at normal ride height. Then tighten.
After fitting, get a wheel alignment. The new arm may shift the geometry slightly. A good alignment protects your tyres and keeps the car straight.
Tools you will usually need
- Jack and axle stands
- Socket set and breaker bar
- Torque wrench
- Ball joint splitter or fork
- Penetrating oil for rusty bolts
For step-by-step torque figures, a repair guide from Haynes is a great help.
Red Flags and Buyer Protection
Be careful if a seller cannot show the code in a photo. A blurry listing may hide a wrong part. Walk away if the price is suspiciously low.
Ask about a warranty. Many used part sellers offer a short guarantee, often 30 to 90 days. Confirm what happens if the part does not fit.
Check frequently asked questions for how sourcing, fitment, and fallback guarantees work. Good sellers stand behind the code they sell.
To understand who you are dealing with, read about Auto128. Buying used genuine parts is safe when the code and condition are clear.
Quick Recap
Control arms and trailing arms keep your wheels in place. Match the exact OEM code to your car before buying used. Check side, position, and bushing condition.
Buy from sellers who show the stamped code and offer a guarantee. Sort out shipping and customs early. Then fit carefully, torque to spec, and get an alignment.
Do that, and a used genuine OEM arm can restore your car's ride for a fraction of the new price.
Frequently asked questions
How do I find the OEM code for my control arm?
Look for a stamped or etched number on the old arm. If you cannot read it, use your VIN at a dealer or ask a parts seller to check the number for your exact car. Never guess by model year alone.
Can I fit a used control arm from a different model?
Only if the OEM code matches. Some cars share the same arm across several models, but the code must be identical. A different code can bolt on yet ruin your alignment and handling.
Are used control arms safe?
Yes, if the metal is straight and the bushings and ball joints are in good shape. Metal arms usually outlast the car. Inspect the rubber for cracks and check for bends or deep rust before fitting.
How much can I save buying a used genuine OEM arm?
Savings vary, but used genuine OEM parts often cost much less than new dealer parts. Sometimes a used original costs less than a new aftermarket arm of unknown quality.
Do I need a wheel alignment after replacing a control arm?
Yes. A new or used arm can shift the suspension geometry slightly. An alignment after fitting protects your tyres and keeps the car tracking straight.
