Neiman and cylinder for Volkswagen Golf 5

Three functions in a single unit

What is commonly known as a ‘Neiman’ – named after the manufacturer who popularised it – is in fact an assembly that fulfils three independent roles.

• The barrel, or lock cylinder, takes the key. This is the part that wears out: the pins and the key wear each other down, and after tens of thousands of operations the key turns with difficulty, then not at all.
• The steering lock itself, a bolt that locks the column when the key is removed. This is the part that gets stuck when the steering wheel is forced in the wrong direction.
• The electrical switch at the rear of the unit supplies power in turn to the accessories, the ignition and the starter motor. Its contacts wear out and overheat.

Identifying which of these three components is at fault avoids having to replace the whole unit when only a single part needs replacing.

Interpreting the symptoms

• The key is difficult to insert or turns with difficulty, and becomes increasingly difficult over time: worn lock cylinder. Try the spare key; if it has been used less, it will turn more easily and confirm the diagnosis.
• The key turns but nothing happens – no warning lights and the starter motordoesn’t engage: the ignition switch.
• The immobiliser remains locked and the key won’t turn: turn the steering wheel slightly in both directions whilst turning the key, without forcing it. The bolt is engaged, not broken.
• The starter motor only engages half the time, sometimes after a tap on the steering wheel: worn contact points or a poorly crimped rear connector.
• The key pops out on its own or the lock assembly turns in the steering column: breakaway fixing screws, which are shear-off screws on many models.

Cylinder only or complete assembly

Replacing just the lock cylinder resolves the vast majority of cases, as it is the part that wears out, and it costs a fraction of the price of the complete lock assembly. It comes with its own set of keys, and this is where you need to think carefully: the new keys will not open the doors, the boot or the fuel cap, as these are still programmed to the old code. You’ll end up having to carry two sets of keys.

There are three possible solutions. Put up with having two keys, which is the simplest and cheapest option. Have the new lock cylinder recoded to your original key by an automotive locksmith, provided the key isn’t too worn. Or replace the door locks at the same time, which only makes sense if they’re also worn out.The full set is justified when the mechanical immobiliser or the ignition lock housing is faulty, or when the vehicle no longer has any keys at all.

Removing an ignition lock: what you need to know beforehand

On most set-ups, the immobiliser unit is secured with shear-off screws: when fitted at the factory, these are tightened until the head breaks off, specifically to prevent them from being unscrewed. Removing them therefore involves drilling into them, splitting them, or using a puller, whilst working in an awkward position under the steering wheel.

Make sure you have new screws to hand: the old ones cannot be reused. Disconnect the battery before carrying out any work, especially on a vehicle fitted with an airbag, and make a note of the rear connector’s reference number before removing it. Finally, check that the anti-theft bolt slides freely in its housing before refitting: if it is stiff, the problem lies in the column and a new ignition lock will jam in the same way.