Hi Rob.
We have just finished fitting Tdci middle row seats to a customers 110 Td5. After doing a lot of research into the complications of the new seats and seeing what others have done on video's I'm quite appalled at the poor jobs people are doing.
We considered removing the rear tub and modifying it or replacing it, but it's a big job and doesn't necessarily make it easier.
The fundamental point of the tdci seats is that they have integral seat belt receivers on the outer seats and full 3 point belt connections in the middle seat. That means that unlike earlier seat designs, the structural mountings are of paramount importance. The various internet guides suggesting 'plates' under the floor or hinge area are at best dangerous and at extreme will cause fatalities. 3 full sized adults strapped to seats that are mounted to the aluminium floor panels will easily rip the mountings out in a high G collision. In my customers case putting their 3 children in sub standard fitted seats was out of the question.
We fitted the genuine chassis brackets to the chassis x member, that also has the rear A frame mounts, and welded them in once a lot of alignment work was done. With the variation of alignment of defender bodies I don't think swapping body tubs would guarantee easy fitment.
The Tdci seats front hinges also do not line up with previous designs and again due to the load now placed on the seats during an accident they MUST be fitted to proper chassis mounted hinge brackets. This is also a time consuming job which would have been easier with the body tub off but can be done in situ.
Finally the wheel arches need to be modified to allow the seats to sit correctly into the floor catches. Here we took extensive measurements from a Tdci 110 at my local main dealer and with a lot of origami modified the wheel arches to 'look' like the Land Rover version, with allowances for the rear tub seat boxes not having the same step, to allow forward facing seats of a Tdci model. Swapping the tub would allow for easier rear forward facing seats to be fitted in the future, but there are ways of achieving that. We are currently looking at a replacement 'part' to allow easy wheel arch modification.
We have not fitted the front Tdci seats, but swapping them should not prove to troublesome.
This maybe a long reply, but, the correct fitting of these seats will enhance the value of your vehicle and help save the lives of those using them, should the worse happen and that is something that cannot be compromised on, in my opinion.
A DIY job is possible but I would suggest, although getting it done professionally will be expensive, the insurance implications are also worth considering, as well as a poorly done job reducing your vehicles value.
Regards
Warwick
