Swapping barn doors / tailgate

[Gryffindor]

In an earlier thread under Members' Berlingos, some of us (mainly MathieuW and myself) wondered whether it might be possible to swap tailgates for barn doors or vice versa. It seemed doubtful; I thought that the body shell would be designed to take either back end on the PSA assembly line; others (especially Zion) thought that it would be way too complicated.
 
I promised to have a good look at the tailgate fixings on my M59 and report back. That was a long time ago but I finally got round to it. In general, we were all more or less right. The body shell can take either type of back end (or at least my M59 tailgate model can), but doing the swap would at least involve drilling out and replacing several spot-welds.
 
So I don’t really think anyone will decide to take such a thing on; however since I did the thinking and took a few photos, I’ll put this post up anyway. At least it bring a partial closure. If someone with a barn door M59 wants to add some photos and observations, that would complete the half-picture I can paint here.
 
I say M59 because I don’t have access to M49s or B9s, so if you do, read this with caution.

 

 
Okay, looking at my tailgate and thinking about barn doors, I decided the problem can be broken down into a list:

1. Tailgate hinges
   
2. Tailgate locking, bottom edge
   
3. Tailgate struts
   
4. Barn door hinges
   
5. Barn door locking, top and bottom
   
6. Bodyshell rear opening, light clusters, etc.
   
7. Looms
   

First, for no real reason, no.2 and no.5. I noticed that the catch at the bottom of my tailgate is not central as I would have expected, but offset to the right – see photo 1. Then I noticed that its clamp in the floor of the body is also offset (of course) but that there’s also a second blanked-off opening mirroring it (photo 2). So it seems clear to me that this tailgate body shell can also have the catches for barn doors fitted to the back of its floor.

1     2    
 
This also means of course that the lower offside catch in a van with barn doors might work with a tailgate, or at least can be swapped for a tailgate catch if the catches work differently.
 
What about the top catches of barn doors? I couldn’t see anything similar at the back of the roof, obvioulsy because the tailgate has no fixing there at all (photo 3). But I had a peek under the headlining – and lo and behold (see photo 4), hidden under it are a pair of depressions in the body’s rear rib with pre-drilled holes, which have to be designed to take the top catches of barn doors.

3     4    

So swapping a tailgate for barn doors would mean cutting a bit out of the headlining; and swapping doors the other way round would leave a small hole at the back of the headlining.

To be continued...

[Gryffindor]

Next, some initial thoughts on no.6. In general, a close look at mine suggests that the back of the bobyshell is essentially completely flat; in other words there are no seriously large bumps or depressions stamped into it which matches one  type of rear door but makes the other type impossible to fit. I did wonder whether the roof overlaps the tops of barn doors to keep rain out; I can’t be certain from the poor eBay photos, but it seems that it does not, which would make it the same as the tailgate version; although a small overlap seems to be added onto the back edge – see photos 7 & 8 taken from eBay. In other words, in both cases the rear profile of the body shell is essentially the same.

5     6    

7     8    

Next I looked at no.1, the tailgate hinges, as best I could without dismantling them. Photos 5 & 6 clearly show the hinge plates which fix to the tailgate; these have three spot-welds and two Torx bolts (why is a mystery). If you look just below them, you can just see smaller hinge plates which are each fixed to the rear edge of the tailgate in three places. At a glance these almost look like spot-welds, but closer up they seem more like flush caps (over bolts or screws?).

Either removing or installing these hinges would be awkward without removing the tailgate from the other hinge plates first, and that would require drilling out spot-welds, so although it could be done in theory, it would be fiddly.

These tailgate hinges do seem like they are simply placed onto the flat rear edge of the body shell, which could suggest that they can also be retrofitted to an ex-barn door model. This time the eBay barn door photos help a bit – they show a shallow depression in the (almost) flat rear edge of the barn door body shell which matches the  location and size of the tailgate hinge brackets and the wiring loom grommets next to them (see later for those).

More follows...

[Gryffindor]

No.3 next, tailgate struts. Their lower ends bolt onto metal brackets which again seem to be simply placed onto the flat rear edge of the body shell, and then spot-welded into place (photos 9 & 10). I can’t tell from the eBay photos what the barn door body shell has here; this spot is just above the light clusters. But I suspect that they have nothing actually fixed to the rear edge at this point, in which case it would be possible to fix tailgate strut brackets to them.

9     10    

No.1 and no.3 together might be the most difficult part of a tailgate installation - these hinges and brackets clearly must be perfectly aligned or the tailgate won’t close properly, but there does not seem any way to make fine adjustments. I guess they are placed accurately by robots on the production line. So anyone doing this would have to take very accurate measurements and think carefully how to get round this problem.

The same might go for part of no.4 as well. As far as I can tell from photos 7 and 8, the top barn door hinges are fixed to the shell’s flat rear edge in the same way, and would also have to be positioned accurately. Each hinge does have two large bolts and so might be adjustable, but there’s no way of telling in the eBay photos what those bolt into – I suspect there’s a second plate spot-welded to the body under the actual hinge, and this might not have any means of adjustment. That the rear edge of the shell is quite flat here (photo 11) probably adds to the problem.

Zion suggested that there may be some sort of extra strengthening for these hinges inside the body shell. I admit this could be a sticking point; the only way forward I can think of is if someone with a barn door model could have a look inside what seem to be plastic vents in the rear edge of the shell just above these hinges (photo 11), to see if there is any strengthening inside the shell.

11    

While you’re at it, also try to see how easy it would be to insert strengthening for barn doors into a tailgate model. If it needs welding to the shell, that would probably ruin the paintwork.

I’ve also got these ‘vents’ on my tailgate model (though curiously they’re just blanking plates without louvres – is that because this is a tailgate model?) – but of course there’s no point looking inside them becauae I donlt have barn door hinges.

As for the lower barn door hinges, the eBay photos aren’t very clear. The hinges seem to have stays which latch onto clips on the inner edge of the door opening instead of the shell’s rear edge, and my tailgate version has pre-drilled holes with blanking plugs in the same place.

But the doors also seem to have lower hinges fixed onto brackets just above the light clusters. If this is right, how are those brackets fixed to the shell?

More...

[Gryffindor]

That just leaves no.7 and the light clusters. The first point is that the looms exit the shell in different places on the two variants; therefore they will be routed differently within the body shell and this might be the second biggest hurdle to leap over. Maybe someone with access to Citroen wiring diags can confirm the loom routing inside the shells?

On the tailgate version there are two looms, each exiting the shell next to one of the tailgate hinges (photos 5 & 6).Comparison with the shallow depression in the eBay photos suggests that these depressions have holes punched into them for tailgaste model looms.

The eBay photos (7 & 8) seem to show the barn door looms coming out of the tops of the light clusters. Is this right? If so, then that would make wiring up barn doors fitted to a tailgate model fairly easy, though the job would require different light clusters, or holes drilled into the current ones.

I haven’t considered electrical equipment fitted to the different types of door (wipers, door locks, lights etc.) because they are probably the same in terms of a list of items (at least for those barn doors with windows and wipers).

Lastly, there is the Diagbox question – even if there’s no change to the presence or absence of rear wipers etc., do we have to tell the van that it’s had a rear end graft?

Even more lastly, I bet there’s stuff I’ve missed!

[MathieuW]

This is great! Hope someone with barn doors will check these things.