How to remove and replace a Thule roof box lock - roofracks.co.uk 

I'm sorry to hear that your key has snapped off in the lock barrel. You will not be able to replace it unless you can remove the broken part of the key. It is often possible to do it yourself with a pair of very fine tweezers. Alternatively, you could try asking a good locksmith, as they often have more sophisticated tools suited to the job. Please note that to extract the key, the barrel must be in either the locked position, or the lock removal position that is shown in the video. If you are unable to remove the broken key then the only other option is to drill the lock out. However, this is quite tricky, and extreme care must be taken to not damage the housing, lock surround, or locking mechanism. You would also then need to manipulate the mechanism into the lock replacement position shown in the video so that you can insert a new replacement barrel. Again, a good locksmith might be able to help with this, and I wouldn't recommend it to anybody not extremely confident at DIY.

It sounds like the locks on either side of your roof box match, which they should, so the key that won't open the locks is the wrong one. I hope this answers your question.

@@roofracks sorry I’m not really explaining myself. Let’s say my Thule key number is n199 and all the barrels are n199 and that’s all great and have no issues. I then stuck in Thule key N150 and it opens the roof box but not the other barrels for roof rack etc

@@donalgalvin5838 If you can open the roof box lock using a different key number to the one that's marked on the face of the lock barrel, then it's likely that the lock housing on the roof box has been worn down due to forcing the mechanism with the wrong key too many times. If this is the case, you would need to replace the lock housing on the box before inserting the barrel into it.

Unfortunately, it is not possible to replace the lock if you do not have the original key. However, you can buy replacement keys if your lock barrel has the number engraved on the face. If it does not, then you will need to ask a locksmith for help, who can hopefully manipulate the lock into the lock removal position so that you can exchange it as shown in the video. I'm afraid that if it were possible to unlock or remove the lock without the original key, then there would be no point in having a key operated lock at all, since somebody could use whatever method this was to get access when the roof box is full of your belongings and it would not be secure at all.

@@roofracks what do you do when the key has broken off in the lock? It still rotates and will open and lock but the broken key is stuck in it, any tips removing?

@@djcurrie32 I am sorry to hear about your broken roof box key. You might be able to remove the broken part using a pair of fine tweezers. Alternatively, contact a good locksmith, who should have some dedicated tools for removing the key. However, please be aware, and make the locksmith aware, that to enable the key to be removed the lid must be closed with the key in either the locked position, or the lock removal position that is shown in the video. Only as a very last resort, the lock can be carefully drilled out, but this can sometimes result in further damage to the locking mechanism, so I would advise that you request that the locksmith does this for you rather than attempting to do it yourself. You would also then need to manipulate the mechanism into the lock replacement position shown in the video so that you can insert a new replacement barrel, which are available from the Spare Parts section of our website. I hope this helps and that you have success with the key removal.