Ignition barrel/housing failure


Registered User
Hi all,

Need help to diagnose this problem:
Inserted ignition key into barrel to start my car after work - as I turned the key I felt something odd, like something inside the ignition barrel broke.
My key now turns all the way around to the stop in position 2 but the car doesn't start.
There's a slight bit of feel where position 1 should be, and the radio comes on, but no dash lights and as I said earlier no actual ignition. Car's stranded at work.

I've taken off the airbag, steering wheel and upper/lower steering column plastics to gain access to the barrel and housing.
Took the barrel out. Checked it. Can't see anything broken.
Gently turned the inner mechanism with a flat screwdriver and sort of feel the position 1 point. But no spring feeling where position 2 should be.

Is there a mechanical part that may have failed inside the ignition housing?

Q1. Which part shall I replace?

Q2. If I replace the mechanical housing, will the existing barrel work (is it the barrel that's programmed to my key?)

Q3. Do you think this job is something I can repair myself or will I have to go to an Audi dealer to have my back pocket rodgered by the corporate money man?

All help and advice welcomed. Really need to get my car back on the road.

Audi A3 1.8T (2wd) 1999 8L AGU


Moon is made of green cheese
Sounds like you need to change the ignition lock housing. Part number 4B0905851B. About £90 new or you can risk a second hand one.

Same thing happened to me a few years ago so I know it's a little tricky to replace but doable. The housing is held with two bolts that can only be removed using a dremel to cut into enough so that you can use a large flat head to unscrew them.


Registered User
Hi all,

I've found the problem. The pointy-outy bit which actually activates the ignition switch has sheared off its casting. So I need to try to get hold of another part to swap in. If anyone might be able to post me one of these pieces I'll happily provide some sort of liquid refreshment in return.

Currently I'm trying to 'glue' the piece back on with metal epoxy putty. If this holds enough for one crank I can get the car home.

Photos attached to explain a little more.

Here's the view of the steering system with everything disconnected. The ignition switch hanging off on the left, the ignition barrel hanging off on the right. The ignition housing in metal finish in the centre below the hub for the steering wheel.

Here's the face on view of the ignition barrel end of the whole assembly. The barrel is hanging there to the left. A little white plastic collar holds all those metal bits inside the ignition housing.

After the little white plastic collar has been eased out, this is the next piece to follow.

Then a retaining ring for the spring.

Then the spring itself.

After this you can turn (counter clockwise I think) and gently pull the final casting from within the housing.

And here's the casting (upside down) that sits inside the ignition housing. It has a spring fitted to its base (the top in this picture) which workes against the inside of the casting against the ignition switch. The little piece to the right of the casting is the irritating little bit which sheared off.

Here's the little piece.

It's supposed to sit as part of the casting as shown above. (This has some splodgy cement around it because I took this while waiting for metal epoxy putty to set.)

Finally here's the piece set with the splodgy cement filed off.

I just tried it in situ - it worked fine for the first few times then it broke again. The shock of the steering lock operation as it snaps into play when the key is withdrawn from the barrel seemed to force the break, though it did survive the first few times.
So I'm currently still at work waiting for my second epoxy fix to go off. I'll file that down, rebuild the ignition. Connect the battery, add my steering wheel and see if I can get ignition and engine turn-over.

Incidentally I tried the loca scrap yard at lunch time. They had an A3 in with the ignition barrel still intact. But of course someone had stolen the key, so I couldn't get the barrel out to try to salvage the working casting from within. So annoying - I could see the bit I needed but no joy.


Registered User
Final update for now - after re-epoxying the casting a second time, rebuilding the ignition housing, barrel and switch, fitting the wheel, and the airbag, I finally turned the key in the barrel....got ignition! Then the piece broke again.
Anyway, I got a couple of guys from work to help give me a push, bump-started the car and drove home. Happy days!
Now I just need to track down a replacement ignition casting. As I said before, I'd be massively grateful if anyone has any leads as to where I can get a replacement part.

I spoke with Canterbury TPS today - they no longer serve private customers. Shame.


Registered User
@tcg Mate! Superb find - I had looked but I must've had too much clutter on my search criteria. I've ordered that piece - hope to be up and running again this weekend. Thank youuuu!


Registered User
Hope it's ok mate,had a moment when I clicked on it a bit later and it had ended...thought you'd missed out :blush: good luck with the jigsaw puzzle,keep us posted.