407 HDi sedan 2008, heater flap repair

[UNM]

Was giving my daughter a lift on xmas day and she complaiend the air con weasnt working. It worked fine on my side of the car, so I checked and sure enough her side was blowing hot air.

I've since pulled the top vents and checked the operation of the flaps.
The directional flaps are both fine.
The blue lower flap (passenger side heater/air-con) has a broken shaft.

I've ordered a repair kit from China and am wondering if anyone here has cut open the heater box and replaced a flap.
If so, I'd appreciate any tips.
There's a few youtube videos, but they all seem to be the drivers side. I'm mostly interested in exactly where to cut and if there is anything inside I need to be careful of when cutting the plastic casing. Also what is the best glue to use (looks like the heater box is polypropylene)?
I may try plastic welding and add some extra glue strengthening, depending on what access is like.

 

[seasink]

Are you certain the flap shaft has broken? More commonly the driving splines on the end of the shaft fail. These are easily inspected by removing the flap motor in the passenger's foot well. It has a splined shaft drive that slips into the flap end.

 

[dmccurtayne]

I’ve done a bunch of these I would suggest getting the best flap kit you can I’ve had to redo customers attempts at glueing the splindles together. Once you cut/repair it that’s it so get the best kit you can from Europe

 

[UNM]

I’ve done a bunch of these I would suggest getting the best flap kit you can I’ve had to redo customers attempts at glueing the splindles together. Once you cut/repair it that’s it so get the best kit you can from Europe

I already ordered a flap kit from ebay - shipping from China.

Based on your comment, I'll check it carefully when (if) it arrives and consider whether to order one from the UK (which generally seems to be a decent source of car parts).

I have seen some youtube videos showing how to add reinforcing to the flaps - do you think that is worthwhile? Mine lasted 220,000km and 15 years, so I am inclined to think it may be a waste of time - the car will likely only last me a few years more.

 

[UNM]

Are you certain the flap shaft has broken? More commonly the driving splines on the end of the shaft fail. These are easily inspected by removing the flap motor in the passenger's foot well. It has a splined shaft drive that slips into the flap end.

Yes, I'm certain the shaft has broken (from my visual inspection). No idea if the splines are also worn, but a new flap will fix that too.

thanks for the suggestion though.