Parking Barrier Spring Replacement: Fixing Sagging Arms

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A parking barrier arm that sags, drops slowly or lifts unevenly usually has worn balance springs or an incorrect counterweight. Replacing the springs and correcting the counterweight restores balance, reduces motor strain and returns the arm to smooth operation.

Recognizing Worn Springs and Counterweights

Most barrier complaints start with the arm itself. A healthy arm stays level when stopped, rises and falls at a steady pace, and holds its position without drifting. When it sags at the tip, hesitates at the top of its travel or slams down, the balancing system is often the cause.

Arm droops when left in the raised position
Uneven speed during lift or lowering
Visible rust, cracks or stretched coils on the springs
Loose or shifted counterweight on the arm

Check these points before touching the motor or electronics.

Safety Before You Start

A barrier arm carries real stored energy. Disconnect power at the source, lock it out and confirm the arm cannot move. Support the arm with a secure prop or a second person before releasing any tension. Never remove a spring while the arm is under load, because a released spring can strike with force. Follow the manufacturer's procedure for your specific model.

Choosing the Right Replacement Spring

Match the replacement spring to the original in wire diameter, coil diameter, free length and rated load. A spring that is too strong will overload the motor and joints, while one that is too weak will leave the arm sagging. Inspect the mounting hardware and end fittings as well, since worn anchors can make a new spring feel loose. If you are unsure of the correct specification, confirm it with the engineer or the equipment supplier before ordering.

Adjusting the Counterweight

The counterweight works with the springs to balance the arm. After installing new springs, check whether the arm stays level when released at mid-travel. If the tip drops, the counterweight may need to move closer to the pivot, and if it rises, it may need to move outward. Secure the counterweight firmly once balance is achieved, and recheck it after a few operating cycles.

Test balance at several positions, not only the top
Tighten all clamps and bolts after adjustment

Testing and Fine-Tuning the Arm

Restore power and run the barrier through several full cycles. Listen for scraping or knocking and watch for uneven speed. Check the limit switches to confirm the arm stops at the correct open and closed positions. Small adjustments to spring tension may be needed to match the arm's speed to the motor's settings. Document the final settings so future maintenance is faster.

Preventive Maintenance Routine

Springs and counterweight hardware benefit from regular inspection rather than emergency replacement. Look for surface rust, flattened coils and loose fasteners during routine service visits. Lubricate pivot points as the manufacturer recommends, and keep the arm and its surroundings free of debris. Early detection avoids the more serious damage that a failed spring can cause to the arm and the drive system.

Frequently asked questions

How do I know if the barrier spring is worn or the motor is failing?

If the arm moves at a normal speed but sags or drifts when stopped, the balance system is the likely cause. If the arm moves slowly, stalls or makes a humming sound without moving, check the motor and drive first.

Can I replace only one spring on a barrier?

Replacing a single spring is generally not recommended, because the two springs share the load and an unmatched pair will unbalance the arm. Replacing both at once gives more consistent results.

Do I need to move the counterweight after replacing springs?

Often yes. New springs change the balance, so check the arm at several positions and adjust the counterweight until it holds level and moves smoothly.

Is it safe to do this work myself?

Spring work involves stored energy and can cause serious injury if handled carelessly. Lock out the power, support the arm and follow the manufacturer's procedure, or ask a qualified technician to handle the job.

Common mistakes to avoid

Replacing springs without checking the counterweight balance and releasing spring tension while the arm is unsupported are the most common errors. Both can damage the motor or cause serious injury.

Our recommendation

Always replace springs in matched pairs, record the original settings before removal, and retest balance at several arm positions before handing the barrier back to the client.

Summary

Worn barrier springs and an off-balance counterweight cause sagging and slow movement. Correct replacement, careful balancing and safe handling restore smooth, reliable operation.

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