Is a loose driver's seat an MOT failure?

Yes, and it is one of the few interior items that can be graded dangerous. An insecure driver's seat, a seat that can move inadvertently, or a backrest that cannot be retained upright are all dangerous defects. A defective seat structure, or a fore-and-aft adjustment mechanism that no longer works as intended, is a major defect.

Can I drive a car with a seat that moves?

You should not. Because the insecure and inadvertent-movement versions are graded dangerous, using the car in that state means using a vehicle in a dangerous condition, with a fine and penalty points quite separately from the failed test. It is a control problem too: a seat that shifts under braking takes your reach to the pedals with it.

Will a seat that does not slide forwards and back fail the MOT?

Not necessarily. A seat that is fixed by design, or one that cannot travel through the manufacturer's full range of adjustment, is not a failure at all. What does fail is an adjustment mechanism that no longer works as intended, and a seat needing manual assistance before the runners lock must be rejected, because the locking should engage automatically in every normal position.

Can I tighten my own seat mounting bolts?

Yes, to the correct torque, and it is sometimes the whole fix. Check what you are tightening into, though: if the captive nut or the floor around it is corroded, that is a prescribed-area problem and becomes a welding job. Any seat with a side airbag, pre-tensioner or occupancy sensor has a live restraint connector underneath, so disconnect the battery first.

How much does it cost to fix an insecure car seat?

An hour of labour with no parts — bolts checked, runners cleaned and greased, a catch adjusted — is £60 to £100 and covers the cheap cases. A good used seat from a breaker is £60 to £200 with about an hour to fit. Electrically adjusted seats, and mounting points that turn out to need welding first, are what take it to £400.

MOT defect file

Driver's seat insecure or will not adjust

Last updated 27 July 2026

Quick answer

The seat moves on its mountings, its runners no longer lock, or the backrest will not stay upright. A seat that shifts under braking is graded dangerous, which makes this one of the few interior items that can stop you driving the car away.

Typical cost: £80–£400
DIY viability: Possible with care

What you might notice

The seat rocks or shifts a little when you brake hard or pull away
A runner that will not latch in some positions, so the seat slides back on its own
A backrest that folds or reclines under your weight instead of holding upright
A recline lever or height adjuster that has to be held or helped before it engages

What causes it

Worn or bent seat runners and a stretched locking catch, most often on a car that has had many different drivers
Corrosion at the seat mounting points in the floor, particularly where a footwell has been damp for a long time
Mounting bolts loosened and never properly retightened, usually after the carpet was lifted or the seat removed for another job
A failed recline mechanism or a broken backrest catch, and on electric seats a stripped adjuster motor or drive gear

Advisory or failure?

The grading distinguishes a mechanism that does not work from a seat that could move on you. A driver's seat with a defective structure is a major defect, and a fore-and-aft adjustment mechanism not working as intended is also a major defect. It escalates to dangerous where the driver's seat is insecure, or where the seat can move inadvertently or the backrest cannot be retained in the upright position — the reasoning being that a seat shifting under braking takes your control of the car with it. Passenger seats are assessed slightly differently: a defective structure or a backrest that will not stay upright is a major defect, and an insecure passenger seat is dangerous, but a passenger seat structure is only treated as defective if it is likely to cause injury. Two things are commonly misunderstood. A seat that is fixed, or that cannot travel through the manufacturer's full range of adjustment, is not a failure at all. And where adjustment needs manual assistance before it locks, it must be rejected, because the locking system is meant to operate automatically in every position provided for normal use.

Can you fix it yourself?

Possible with care

Retightening seat bolts to the correct torque is well within reach and sometimes the entire fix, but check what you are tightening into: if the captive nut or the floor around it is corroded, you have a prescribed-area problem rather than a loose bolt, and that becomes a welding job. Swapping a complete seat from a breaker is bolt-in on most cars. The trap is electrical — any seat with a pre-tensioner, side airbag or occupancy sensor has a live restraint connector under it, so disconnect the battery and wait for the manufacturer's stated discharge time before unplugging anything, or you will trigger an airbag fault at best. Runner and recline mechanisms can sometimes be freed with cleaning and the correct grease, but a stretched latch is not something to adjust and hope.

What it costs

At the cheap end this is an hour of labour and no parts — bolts checked, runners cleaned and greased, a catch adjusted — so £60 to £100. A good used seat from a breaker is £60 to £200 depending on the car and trim, with about an hour to fit, which covers most worn-runner cases. Repairing rather than replacing a recline mechanism is rarely worth the labour. The top of the band is an electrically adjusted seat, where the motor and module cost considerably more and may need coding, or a mounting point that turns out to be corroded and has to be welded before anything is bolted back to it.

What happens if you ignore it

A seat that moves when you brake is a control problem, not a comfort one: you lose your reach to the pedals and your position relative to the wheel at the exact moment you need both. A backrest that folds under load also puts you out of position for the belt and the airbag, so the restraint system works against a body that is not where it expects. Because the insecure and inadvertent-movement versions are graded dangerous, driving the car in that condition means using a vehicle in a dangerous condition, which carries a fine and penalty points quite separately from the failed test.

Common questions

Is a loose driver's seat an MOT failure?: Yes, and it is one of the few interior items that can be graded dangerous. An insecure driver's seat, a seat that can move inadvertently, or a backrest that cannot be retained upright are all dangerous defects. A defective seat structure, or a fore-and-aft adjustment mechanism that no longer works as intended, is a major defect.
Can I drive a car with a seat that moves?: You should not. Because the insecure and inadvertent-movement versions are graded dangerous, using the car in that state means using a vehicle in a dangerous condition, with a fine and penalty points quite separately from the failed test. It is a control problem too: a seat that shifts under braking takes your reach to the pedals with it.
Will a seat that does not slide forwards and back fail the MOT?: Not necessarily. A seat that is fixed by design, or one that cannot travel through the manufacturer's full range of adjustment, is not a failure at all. What does fail is an adjustment mechanism that no longer works as intended, and a seat needing manual assistance before the runners lock must be rejected, because the locking should engage automatically in every normal position.
Can I tighten my own seat mounting bolts?: Yes, to the correct torque, and it is sometimes the whole fix. Check what you are tightening into, though: if the captive nut or the floor around it is corroded, that is a prescribed-area problem and becomes a welding job. Any seat with a side airbag, pre-tensioner or occupancy sensor has a live restraint connector underneath, so disconnect the battery first.
How much does it cost to fix an insecure car seat?: An hour of labour with no parts — bolts checked, runners cleaned and greased, a catch adjusted — is £60 to £100 and covers the cheap cases. A good used seat from a breaker is £60 to £200 with about an hour to fit. Electrically adjusted seats, and mounting points that turn out to need welding first, are what take it to £400.

Cars this happens to most

Of every model with at least 2,000 tests in the DVSA data, these record driver's seat insecure or will not adjust on the largest share of their MOTs. Across all of them the typical rate is 0.1% of tests.

Citroen C4 Grand Spacetourer0.3%
13 times in 3,769 tests
Aston Martin Vantage0.1%
7 times in 5,028 tests
Kia Xceed 40.1%
2 times in 2,244 tests
BMW X70.1%
2 times in 2,595 tests
Fiat 500E LA Prima0.1%
2 times in 3,009 tests
Fiat 500E0.0%
2 times in 4,131 tests
Mercedes-Benz Eqe0.0%
1 times in 2,343 tests
Kia EV60.0%
2 times in 6,515 tests

A high rate here is a property of the fleet as much as the car: these models skew old, and almost everything fails more with age. It is a reason to check the item on a used example, not proof the model is badly built. Models with fewer than 2,000 tests are left out because a rate drawn from a few hundred cars moves too much to rank.

Pass rates for every make and model

Warning lights behind this

This defect is what a tester writes down. What you see from the driver’s seat is a symbol, and it is worth checking which one, because manufacturers reuse the same shape for more than one system.

This is general guidance, not a diagnosis. The severity DVSA records depends on the specific fault found, so the same item can appear as an advisory on one test and a failure on another. Ask a qualified tester or mechanic to inspect the vehicle.

Has this been recorded on your car?

Check the full MOT history for any UK registration.