Barn Door Repair
When I bought my Patrol, it had a significant crack on the outer skin of the right barn-door side,
more or less in line with the bottom of the window.
During my initial hunt for a Patrol I noticed cracks on several of the vehicles which I looked at.
The crack on the specific vehicle I bought was one of the worst.
I read up on this forum as well as on the Australian Patrol forum about this problem.
A popular culprit “has been identified” as bigger / heavier spare wheels as well as slamming of the door.
My vehicle has a standard size spare wheel…. This argument is not valid in my case.
However, it had a sagging / misaligned RH barn door.
Below I will describe the method of repair which I applied to repair the cracked barn door.
In my opinion the root cause of the barndoor cracking is the design of the door itself.
The crack on all the Patrols with this problem appears to be always exactly in the same position.
The doorframe has been reinforced with an additional panel on the inside.
The crack runs within 1mm above this reinforcement plate.
(See Image 1)
When closing the door one needs to apply a certain force in order to ensure that all 2 door locks (bottom and top) engage properly, otherwise the “door open” signal on the dashboard stays lighted. However, forcefully closing the door puts a bending stress on it. The stress is highest in the middle of the door - at the bottom of the window. It has the same effect as bending a thin piece of metal up and down over a table edge until it breaks off.
In this case, it is the reinforcement inside the doorframe representing the tables edge.
I am quite certain that this problem would not occur If this reinforcement piece were to be significantly longer at the top. The forces created when closing the barndoor will obviously be even higher when the hinges are worn causing, a sagging of the barndoor. The Fix:
In the Ausi Patrol Forum someone posted a DIY method of fixing the problem.
He inserted a 40-cm steel reinforcement bar which he MIG-welded onto the inside of the doorframe by means of holes which he drilled beforehand into the actual skin of the barndoor.
I visited various panel beaters to request a quote on the repair.
Some were not prepared to do this kind of repair, others quoted between 5 and 6 K.
My concern was that one does not really know how well such a repair would be done by a panel beater… and will it last ?
On the other hand, I was not at all convinced that I could do a DIY job using the before mentioned MIG welding method.
I eventually decided to do the repair myself by using a different approach:
1) I stripped inside door panel, wiper blade motor assembly, door lock top, connecting rods + cables.
2) I cut a strip ~ 150 x 20 mm on the inside of the doorframe as access-hole with a Dremel tool at the height of the cracked outer skin.
(See Image 2)
(See image 3).
This picture was taken through the access-hole and shows the crack of the outer skin from inside the doorframe, exactly were the reinforcement piece ends.
3) I decided to do a sandwich reinforcement which wedges the cracked panel between two outer metal strips and two inner strips.
The outer strips are ~ 6 x 400 mm for the bigger one and about 3 x 200 mm for the smaller one. Holes for bolting were pre-drilled, and the holes in the inner strips threaded.
Outer and inner strips were coated with a layer of metal epoxy, then screwed together with bolts.
Nuts can’t be used with the bolts since it is too difficult to attach them in the time available (speed was needed due setting time of the epoxy). The use of nuts would also limit the space inside the doorframe to the extent that movement of the connecting rod (door locks) could be impaired.
The epoxy layer between the reinforcement strips and the body skin fulfills two functions:
a) It ensures that the reinforcement metal strip bonds 100% with the vehicle skin and not just at certain points as with a screw connection or welding points.
b) It gives additional strength.
(See Image 4)
After the reinforcement process as described above was complete, the remaining task was to smooth out the reinforced area, then apply primer and paint.
(See Image 5,6 and 7)
4) Thereafter came the reassembly of the components removed earlier.
5) Another important task was to readjust the door so that it is perfectly aligned with the horizontal guide / striker at the bottom.
What I did was to support the weight of the door with a trolley jack (raised on pallets). I first tried to loosen the screws (3 per hinge) on the c-pillar and then tried to lift the door with the trolley jack.
The part of the hinge fitted to the c-pillar allows only very limited adjustment.
Thereafter I repeated this process, but on the other side of the door hinge which is attached to the barndoor. The two screws per hinge on the barndoor side can be accessed by removing the door inner panel. This gave the desired adjustment level. The door is now adjusted properly and does not have to endure additional stress during the closing process.
So far so good, (after ~ 4 weeks & ~ 1000 km).