How to Repair and Replace Clock Springs

Clock springs, also called mainsprings, are the power source for many mechanical clocks. They store energy when wound and release it slowly to drive the gears, pendulum, and hands. When a spring breaks or loses strength, the clock stops keeping time. Fortunately, you can repair or replace a clock spring with the right knowledge and care.

This guide explains step by step how to identify problems with clock springs, handle them safely, and restore your clock’s performance.

1. Understand the Function of a Clock Spring

A clock spring works like a coiled piece of energy. When you wind the key, the spring tightens and stores energy. As it unwinds, that stored energy powers the movement.

Over time, clock springs can weaken, break, or stick. This results in clocks that run for only a few hours, lose accuracy, or stop completely. Knowing the role of the spring helps you troubleshoot when problems appear.

2. Identify Common Spring Problems

Before you attempt repairs, look for these common issues:

• Broken spring: The spring no longer winds and may rattle inside the barrel.
• Slipping spring: The clock won’t stay wound because the inner hook has slipped.
• Set spring: The spring has weakened and doesn’t provide enough power to run the clock for a full cycle.
• Dirty or gummed spring: Old oil or dirt prevents smooth unwinding.

Each of these problems requires a different solution, so proper diagnosis matters.

3. Safely Remove the Movement

Repairing a spring always begins with removing the movement from the clock case. Carefully document each step so you can reassemble later. Use gloves and a clean workspace.

Important: Never remove a wound mainspring without letting it down first. Releasing a spring under tension can cause injury. Always let down the spring completely using the proper let-down tool before working on it.

4. Decide Between Repair or Replacement

Once you remove the movement, you’ll need to decide whether to repair or replace the spring:

• Repair: Sometimes cleaning and re-oiling the spring restores its function. This works if the spring is dirty or slightly set.
• Replace: If the spring is broken or badly worn, replacement is the only safe option.

At this point, many clock owners wonder whether they should attempt the work themselves or rely on professional service. That’s why Clockworks, Inc. offers both professional clock cleaning and repair services as well as specialized tools for do-it-yourself maintenance. From let-down keys to mainspring winders and complete spring kits, we carry everything you need to handle the job properly.

5. Clean and Oil the Spring

If your spring is dirty or sluggish, you may restore it with cleaning and oiling. Here’s how:

1. Remove the spring from the barrel carefully.
2. Clean it with a clock-safe cleaning solution.
3. Dry it thoroughly.
4. Apply a light coat of high-quality clock oil across the entire surface.

A freshly cleaned and oiled spring can make a clock run like new again.

6. Replace a Broken Spring

If the spring is broken, you’ll need to install a new one. Measure the original spring’s width, thickness, and length before ordering a replacement. Install the new spring into the barrel, ensuring both hooks catch securely. Always use a mainspring winder tool for safety—forcing a spring by hand risks damage or injury.

7. Reassemble the Movement

After repairing or replacing the spring, carefully reinstall the movement into the case. Ensure the gears mesh correctly and that no levers or pivots are bent during reassembly. Once secured, wind the spring slightly to test operation before closing the case.

8. Regulate and Test

Allow the clock to run for several days to confirm the spring delivers consistent power. Check for:

• Proper timekeeping.
• Full run time (usually 7 or 8 days for most mantel and wall clocks).
• Smooth, even operation of the gears.

If the clock loses time or stops early, the spring may still be weak, or another part of the movement may require service.

9. Prevent Future Spring Issues

You can extend the life of your clock springs with simple maintenance:

• Wind your clock regularly and consistently.
• Avoid over-winding; stop when you feel resistance.
• Keep the clock clean and dust-free.
• Have the movement cleaned and oiled every 5–7 years.

Routine care prevents springs from breaking down prematurely.

Conclusion

Clock springs are the heartbeat of mechanical clocks, storing and releasing the power that keeps time moving. By understanding their function, recognizing problems, and safely repairing or replacing them, you can keep your clock running smoothly for years. And when the work goes beyond what you want to do at home, Clockworks, Inc. provides professional repair, cleaning, and all the tools and parts you need.

For assistance, visit Clockworks.com or email us at clockworks@clockworks.com.

Updated on: 29/09/2025