Ignition Lock Cylinder Guide for the 1971-1977 Mercury Comet
Having trouble starting your Comet? Your ignition lock cylinder might be the problem.
- Failure symptoms often include a key that's hard to turn, gets stuck, or won't start the car.
- Replacement is a simple DIY job for most owners, requiring only a paperclip and basic tools.
- A new ignition key will not match your original door locks.
- Make sure your problem is the lock cylinder and not the electronic ignition switch before buying parts.
Is Your Ignition Lock Cylinder Failing?
Over many years, the small metal parts inside the ignition lock cylinder wear out from turning the key thousands of times. This wear and tear can cause a number of frustrating issues. If you're experiencing problems with your 1971-1977 Mercury Comet, a bad lock cylinder could be the reason. It's a common issue on older cars.
Distinguishing Between the Lock Cylinder and the Ignition Switch
It's important to know the difference between two parts that work together: the ignition lock cylinder and the ignition switch. The lock cylinder is the mechanical part your key goes into. The ignition switch is the electronic part behind it that the cylinder operates. While a bad lock cylinder can prevent the car from starting, a bad ignition switch can cause the car to stall while driving or have other electrical problems. Sometimes, both parts need to be replaced, but you should first figure out which one is causing your specific problem.
Known Issues, Recalls, and TSBs
No specific recalls or Technical Service Bulletins (TSBs) from the manufacturer were found for the ignition lock cylinder on the 1971-1977 Mercury Comet. Searches of the National Highway Traffic Safety Administration (NHTSA) database did not show any actions related to this specific part. However, a recall was issued for 1971-1973 Comets related to fuel tanks in rear-end collisions. Any issues with the ignition lock cylinder today are typically due to normal wear and tear over 50+ years of use.
Choosing the Right Aftermarket Ignition Lock Cylinder
Since new original equipment (OEM) parts from Ford are no longer made for this vehicle, you will be choosing from aftermarket brands. For the Mercury Comet, this is the standard and most practical option.
- Standard Ignition (Standard Motor Products): This is a well-respected brand in the aftermarket with over 100 years of experience. They are known for making high-quality replacement parts that meet or exceed original specifications. Mechanics often trust Standard for its precision and durability. For a critical part like the ignition, Standard is a reliable choice.
- Replacement (Generic/Store Brand): This brand offers a more budget-friendly option. While it can be a good value, the quality can sometimes be inconsistent. Some users of similar generic parts report that they fit and work well, while others have had issues with fitment requiring modification. If you choose a generic brand, it's a good idea to inspect the part carefully and compare it to your old one before installation.
A Note on Keys
Your new aftermarket ignition lock cylinder will come with a new set of keys. These keys will not match your original door and trunk locks. You will have to carry two keys: one for the ignition and one for the doors and trunk. Some owners take the new cylinder to a locksmith to have it re-keyed to match their original keys, but this adds to the cost.
| Part Type | Price Range |
|---|---|
| New Aftermarket (Replacement, Standard Ignition) | $21.83 - $35.44 |
| Shop Labor for Installation | $90 - $150 |
Frequently Asked Questions (FAQ)
How difficult is it to replace the ignition lock cylinder on a Comet?
For a 1971-1977 Mercury Comet, this is a relatively easy job for a DIYer. The process involves turning the key to the 'accessory' or 'run' position and inserting a paperclip or small wire into a release hole on the face of the cylinder to depress a retaining pin. The cylinder can then be pulled out. 🎬 Watch a demonstration of this removal and replacement process. The entire job can usually be done in under 30 minutes with basic tools.
🎬 See how to replace the cylinder on similar Ford models.Do I need any special tools?
No, typically the only special tool you might need is a straightened paperclip or a small stiff wire to push the release pin. Otherwise, basic hand tools are all that's required.
My key is stuck and won't turn. How can I remove the cylinder?
If the key won't turn to the 'accessory' position, you cannot depress the release pin. In this case, removal becomes more difficult. Some owners have had success lubricating the lock and wiggling the key. If that fails, a locksmith may be needed, or in a worst-case scenario, the cylinder may need to be drilled out by a professional.
Will a new lock cylinder fix my car's starting problem?
It depends. If the problem is that the key is hard to turn or won't turn at all, a new cylinder will likely fix it. If you turn the key and nothing happens at all (no lights, no sounds), the problem could also be the ignition switch, battery, starter solenoid, or wiring. It's important to diagnose the problem correctly before buying parts.
Helpful Videos
Technical Specifications
OEM Part Numbers: D4AZ-11582-A
Dash-mounted mechanical tumbler lock cylinder. Includes lock cylinder, two keys, and retaining clip.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.