The trunk on an old car gets opened a few times a year. The lock sits facing the weather, collects dust from every gravel road in Hood County, and never sees a drop of lubricant. Then the day you need the spare tire, the key will not turn. Call or text (817) 214-2934 if the checks below do not open it. Most of them take a minute and cost nothing.
Quick Answer
As of October 2026, a classic car trunk that will not open with the key is most often caused by the wrong key (many older cars used a separate key for the trunk), a dry or dirty lock cylinder, or a latch held tight by the lid. Try every key you own, add a dry lock lubricant, and press down firmly on the lid while turning. If that fails, a locksmith can open the trunk without damage and cut a correct key: a key cut to a lock that works is $75–$125 in Granbury, and a key made with no original is $100–$300.
First: Are You Using the Right Key?
This is the cause more often than any mechanical fault, and it is the one owners of inherited or recently bought classics do not expect.
For decades, American cars were delivered with two different keys. One worked the ignition and the doors. The other worked the trunk and the glovebox. The idea was that you could hand a parking attendant the ignition key and keep the trunk and glovebox locked.
On most General Motors cars of the 1960s through the 1980s, the two keys had different head shapes so they could be told apart by feel: one square, one round or oval. Ford and Chrysler used the same two-key idea with their own head shapes.
Two things follow from that:
- The key that starts the car may never have been meant to open the trunk. It will slide in part way, or all the way, and simply not turn.
- The trunk key is the one that goes missing. It is used rarely, so it ends up in a drawer, on a different ring, or sold with the previous owner's house keys.
So before anything else, gather every key that came with the car and try each one in the trunk, gently. Then try the key that opens the glovebox. On a two-key car, the glovebox key and the trunk key are the same key.
If you find no key that fits, you have not got a broken lock. You have a missing key, which is a different and usually cheaper problem. It is covered further down.
If the Right Key Goes In and Will Not Turn
Work through these in order. Do not skip ahead to force.
1. Take the load off the latch
A trunk lid sits on a rubber seal and is pulled down against it by the latch. If the seal is new and stiff, the lid is slightly out of alignment, or something in the trunk is pushing up on the lid, the latch is under load and the lock cannot rotate it.
Press down firmly on the lid, right above the lock, with the flat of one hand. Hold it down and turn the key with the other. This releases more stuck trunks than any tool.
2. Lubricate the cylinder properly
Use a dry lock lubricant, either graphite or a PTFE-based spray made for locks. Put a small amount into the keyway, insert the key, and work it in and out a dozen times before trying to turn it.
Avoid oil and general-purpose penetrating sprays if you can. They work for a week and then hold dust, and on a car that lives on gravel roads the lock ends up worse than before.
3. Move the dust shutter
Many trunk locks have a small spring-loaded cover over the keyway. On an old car it can stick half-closed or bend inward, and the key then stops short of fully seated. Look into the keyway with a light. The key must go in to its full depth. A key that is even slightly short of fully seated will not turn.
4. Check the key itself
Hold the key up to the light and look along the blade. Worn keys have rounded cuts and a polished, thin look. If the key is a copy of a copy, it may be worn or mis-cut just enough to work the newer glovebox lock and not the stiff trunk lock. If you have two trunk keys, try the other.
5. Stop before the key bends
Trunk keys on older cars are plain brass or nickel-silver. They twist, and then they snap, and a snapped key in a trunk lock turns a simple job into an extraction. If you are putting enough force on the key to feel it flex, stop there.
If the Key Turns and the Trunk Still Will Not Open
Now the lock is working and the fault is behind it.
The key turns freely, all the way round, with no resistance. The tailpiece on the back of the cylinder has come off the latch, or the cylinder's retainer has let go and the whole lock is spinning in its hole. The latch is no longer connected to the key.
The key turns to its stop and you hear a click, and the lid stays down. The latch released and the lid is stuck. This is usually a seal bonded to fresh paint, a lid out of alignment, or tired springs or torsion bars that no longer lift the lid. Press down on the lid, turn the key, hold it turned, and lift at the edge of the lid.
The key turns part way and stops hard. The latch mechanism is corroded or bent. This is common on cars that have had a rear-end repair at some point in their lives.
On some classics from the late 1970s onward there is also a cable or electric trunk release inside the car. If it has one, try it. If the cable release works and the key does not, the fault is in the lock or its tailpiece. If neither works, the fault is in the latch.
Likely Causes and What Each Costs
| What you find | Likely cause | Fix | Typical Granbury range (October 2026) |
|---|---|---|---|
| No key fits or turns | Separate trunk key missing | Key made to the trunk lock | $100–$300 with no original |
| Right key, stiff and gritty | Dry, dirty cylinder | Clean and lubricate | Often a do-it-yourself fix |
| Right key works when the lid is pressed down | Latch under load | Adjust the striker or bumpers | A body or mechanical adjustment |
| Key is thin and rounded | Worn key | New key cut to the lock | $75–$125 |
| Key snapped in the lock | Forced or brittle key | Extraction, then a new key | Low end of our $75–$350 range |
| Key spins freely | Tailpiece or retainer failed | Trunk opened, lock refitted | Quoted after we see it |
| You want one key for everything | Two-key system | Trunk and glovebox rekeyed to the ignition key | Quoted per vehicle |
| Keys are locked in the trunk | Lockout | Damage-free entry | From $50–$75 for vehicle entry; trunk-only access quoted first |
The key prices are the same bands as our classic car key replacement cost guide. Mobile service inside 25 miles of Granbury is included, with no separate trip fee.
When the Trunk Key Is Simply Gone
This is the most common version of the call, and it has a clean answer.
A key can be made to the trunk lock without the original. The usual methods on an older car:
- Read the glovebox lock. On a two-key car the glovebox and trunk share a key, and the glovebox lock is small, reachable, and often easy to remove. On some older cars a key code is stamped on the lock itself.
- Decode the trunk cylinder in place. The cuts are read through the keyway with the lock still in the car.
- Pick the lock open, then remove the cylinder. With the trunk open, the cylinder comes out from inside the lid and can be read directly.
None of these involves drilling. Drilling a trunk lock on a classic is a last resort, because a correct replacement cylinder may be hard to find and the chrome bezel around it is often harder to find still.
Once the cuts are known, a key is cut and tested. That is the $100–$300 job. If you would prefer never to deal with two keys again, the trunk and glovebox can be set to match the ignition key on the same visit. Our guide to putting a classic car on one key explains how that is quoted.
When the Keys Are Locked in the Trunk
It happens at car shows on the Granbury square and at the boat ramp alike. You set the keys down next to the folding chairs and shut the lid.
What you can try:
- A spare ignition and door key gets you into the cabin. From there, some cars give access to the trunk by removing or folding the rear seat back. On many older sedans the seat back lifts off hooks once the bottom cushion is out. A steel panel or a fuel tank blocks the way on others.
- An interior trunk release, if the car has one and the glovebox is not locked over it.
What we do when that fails: open the car without damage if it is locked, then open the trunk lock by picking it. A classic trunk lock is a simple wafer lock and in good condition it opens without harm to the lock or the paint. Our locked out of a classic car guide covers the cabin side of the job, and our car lockout service page covers pricing for entry.
Do Not Do These
We see the results of all of them.
- Do not pry the lid. Trunk lids on classics are large, thin panels. A pry bar at the edge puts a crease in the lid and the quarter panel that costs many times what a locksmith does.
- Do not hammer a screwdriver into the keyway. It destroys the lock, usually without opening the trunk, and leaves a cylinder that now has to be drilled.
- Do not flood the lock with oil in winter. Thick oil in a cold lock makes the wafers sluggish.
- Do not keep turning a key that spins freely. The lock is disconnected. More turning does nothing and may drop the tailpiece into the lid.
- Do not drill unless you already have the replacement lock in your hand.
After It Is Open: Stop It Happening Again
A few minutes of attention once the lid is up saves the next call.
- Lubricate the cylinder and the latch. Dry lubricant in the keyway, a light grease on the latch and striker.
- Check the lid alignment. If you had to press down to release it, the striker or the rubber bumpers need adjusting. A body shop or a patient owner with a wrench can do it.
- Have a spare trunk key cut, and keep it somewhere other than the trunk.
- Label the keys. A dab of paint on the trunk key saves the next owner the same confusion.
- Use the lock. Turning it every few weeks keeps the wafers free.
If the door locks are stiff as well, the cause is usually the same. Our guide to a classic car door key that won't turn covers the door side.
When to Call a Locksmith
Call when:
- No key you own fits the trunk.
- The correct key will not turn after lubricating and pressing the lid down.
- The key has broken off in the lock.
- The key spins with no effect.
- The keys are inside the trunk and you cannot get to it through the cabin.
- You want the trunk on the same key as the ignition.
Have the year, make, and model ready, and tell us what the key does. We will ask for proof of ownership, title or registration with matching ID, before opening anything. That is standard practice for any licensed locksmith in Texas, where the trade is regulated by the Texas Department of Public Safety Private Security Program, and it protects you as much as anyone.
Frequently Asked Questions
Why won't my ignition key open the trunk on my classic car? Many older American cars were delivered with two keys: one for the ignition and doors, and a second for the trunk and glovebox. The ignition key was never meant to open the trunk. Try the key that opens the glovebox.
How much does it cost to get a trunk key made for a classic car in Granbury? As of October 2026, a key made with no original runs $100–$300, because the lock has to be decoded first. If you have a key that works and want a new one cut to the lock, it is $75–$125.
Can a locksmith open a classic car trunk without drilling? Yes, in most cases. A classic trunk lock is a simple wafer lock that can be picked or decoded. Drilling is a last resort, because correct replacement locks and bezels can be hard to find.
The key turns but the trunk will not open. What is wrong? If the key spins freely, the tailpiece behind the lock has come off the latch. If it turns to a stop and clicks, the latch has released and the lid is stuck on its seal or out of alignment. Press down on the lid, turn and hold the key, and lift at the edge.
What should I spray in a stuck trunk lock? A dry lock lubricant, graphite or PTFE-based. Work the key in and out several times before turning. Avoid heavy oils, which collect dust and make the lock worse over time.
I locked my keys in the trunk at a car show. What do I do? If you can get into the cabin, check for an interior trunk release or access behind the rear seat. If not, call us. We open the car and the trunk lock without damage, and we come to you anywhere inside 25 miles of Granbury.
Can you make the trunk work with my ignition key? Yes. The trunk and glovebox cylinders can be rekeyed to match the ignition and door key, so the car runs on one key. It is quoted per vehicle, based on the number and condition of the cylinders.
Do I need to prove I own the car? Yes. We check the title or registration against your ID before opening a vehicle or making a key. It is required practice and it protects owners.
Get the Lid Up Without Marking the Paint
Most stuck trunks on older cars come down to a key question, not a broken lock. Tell us the year and model and what the key does when you try it, and we can usually tell you on the phone which of these you have. Call or text (817) 214-2934, weekdays 8:00 AM to 7:00 PM, Saturdays 8:00 AM to 5:00 PM, with 24/7 emergency availability for lockouts. You can also request service through our contact page or read about our lock rekey service.