Main Chassis bar won't lock on one side

We had a similar problem, the right-hand hinge of the frame would not lock and the button was permanently down. What had happened was the handle extension switch housing had come unscrewed and slipped up the frame, causing a small spring to fall out. The lock switches each have a spring which pushes down on a rod inside the frame to lock the hinge. To access the spring, unscrew the handle extension housing and slide it up the aluminum frame. I replaced the missing spring and the frame works perfectly. If the problem is with the spring, this should work. Alternatively the problem may lie inside the lock switch housing, which contains a very simple mechanism which slides the lock rod up and down. This can be unscrewed as well. As far as I can tell, the actual hinge assembly itself is a sealed unit and can't be opened, but hopefully, you won't have to.
Good luck,
Ben

The locking mechanism is rather week and is easy to break. The whole outer ring fixed to the handle needs replacing which is easy enough to do but getting the part is much more difficult. I'll post more info if I get the part. Bugaboo at present say they only supply the whole chassis!

Hi to all in need of the spare part to fix this problem for good. Friends of mine have also suffered with issue and i have replicated the part that brakes in a high quality 5 series aluminuim and removed the basic stress points that the original design had. I have posted a link to ebay where i am now currently selling this successful replacement/upgrade.
Regards, Mat.

http://cgi.ebay.co.uk/Bugaboo-Chameleon-spare-parts_W0QQitemZ230440755448QQcmdZViewItemQQptZUK_Baby_Pushchair_Accessories_parts_ET?hash=item35a756e0f8

Problem suggests that you have not followed the user handling procedures correctly and hence damaged the handle lock. Now examine the handle lock on the equipment on the left and right side to compare and identify the damage.If you have identified then check whether this damaged part is fastened to the equipment as a sub part if yes then use proper tools to extract the damaged part and carry it to the store. Pick up the damaged part from the store and replace it your self .Please carry out the safe operation check of the equipment prior to re-using. If you are not able to identify the damaged part then consult the sevice engineer. Use of the equipment without handle lock defect fix is not recommended for you.