Patrol 4x4 - Nissan Patrol Forum banner
1 - 7 of 7 Posts

·
Registered
nissan
Joined
·
24 Posts
Discussion Starter · #1 ·
The following is a D I Y how to repair stress cracks in the rear barn door.
I have made this a two part process. Step 1 and 2

Step 1.

As per this Pic.



I have read the posts where members have had to remove the rear window to achieve this fix. This is mainly due to the fact that the stress crack was far worse than mine.
The trick here is to catch this problem before it gets worse. I would suggest that if you intend on upsizing your tyres then defiantly make this a must do....

OK back to basics...
Allow approx. 4 to 6 hours to complete.
Tools needed..

Mash Hammer. ( Heavy hammer )
Welder ( Mig is preferred )
Tape
Small angle Grinder
Pencil
Electric Drill
Drill Bits 3mm and 8mm
Star Screw Driver
clamps.

Start by removing the inside door trim and skin.
Take care when removing the plastic fixings plugs.
Carefully remove the plastic dust cover from the right side of the door.(This will be used again )
Remove the wiper blade arm from the outside of the door.
You are then able to remove the three bolts holding the wiper motor to the inside of the door. Carefully take the motor assembly off the door.
Remove all wiring that leads up the centre pillar.
Remove the locking mechanism from the top of the door and the rod too.
You should end up with this..


The next step.
Material needed.
20 x 20 RHS 400mm long.
30mm x 3mm Flat 400mm long.
20mm x 2mm flat 2 @ 200mm long.

Take the RHS place it over two pieces of timber ( Like a Bridge ) and form it to suit the shape of the door as per pic.



What I did from here.
Welded 20mm flat approx 200mm long to the top of the RHS.
I did this so the RHS will be flush with the existing support.
As per this pic.


The 30mm flat is welded to the side if the RHS for support, you will need to shape this to suite the angle of the RHS.
To understand this fully you will need to study the area where this will fit, take note of the existing reinforcement the RHS needs to be packed out to fit tight.
Looking at the door from the inside, the RHS is bent to shape with a packer at the top and one at the bottom right side. The 400mm flat is welded on the left side and trimmed to suit the shape of the door cavity.

Sorry I forgot to take a pic at this point..:(

You will need to test the fit. Once you are happy tap it into place so that you end up with 200mm above and below the crack.
This pic gives you an idea of the final fit.
Note this pic was taken at the last stage. Do not fit the wiring or door hardware yet !!!


Now its time to Drill some holes.
We are going to setup for the welding of the RHS to the door frame.
You will need to drill holes through the door into the RHS taking care not to drill through the RHS. I used the small drill as a pilot hole then the larger drill bit.
Here is what it should look like.


Please go to next post for step 2.
 

·
Registered
nissan
Joined
·
24 Posts
Discussion Starter · #2 ·
Rear Door Repair Step 2.

Rear Door Repair Step 2.

This next step is achieved by using a mig welder. This is preferred as it can be set to weld thin steel.
The object here is to fill the holes with weld making sure you weld the RHS first then start to fill the hole. (This is a form of spot welding)Be careful not to burn the metal, try making small welds allowing it to cool and then welding again until all the holes are filled. It should look like this..

Grind the welds until level with existing surface taking care not to throw sparks towards any glass surfaces.

Apply Body filler.

Body filler sanded smooth ready for paint.




The final job should look like this viewing from the inside of the door.

Note that I have positioned the top lock rod through the RHS and made some slight adjustments to allow it to operate smoothly. The wiring to was installed back the same.
Now all you have to do is put the Hardware back onto the door and refit the trims and your done.
If you have any questions please feel free to contact me.
Regards Nuke.
 

·
Registered
Joined
·
38 Posts
Barn Door Cracking

Hi Nuke,

Following with interest your steps to repair the crack. I know it's only recent, but how is the widest crack adjacent to the black window strip holding up? That is the bit that concerns me. Need to repair mine soon.

Regards

Rusty
 

·
Registered
nissan patrol gq
Joined
·
306 Posts
Hi guys/gals,
I too have had the crack of death in my RHS barn door and came across this DIY as well as another on an other site.
I set out to carry out this repair but only had a stick welder. I got a few plugged up top and down low but it was getting a little too hot for the thin gauge metal. I opted for pop rivets to hold it everywhere else and it has worked great. So if, like me, you don't have a TIG/MIG pop rivets work just fine. You'll have to spend the extra time getting the bar shape exactly right but may make things easier for you.
 

·
Registered
nissan
Joined
·
60 Posts
Big thanks for this thread :D

Fixed three doors in the last two weeks. The one on my car, one on a friends and one spare. Have access to an experienced welder (son), Used TIG on the crack to keep heat down near the window and MIG on the plug welds. Wet rag to cool after each weld.

As I said, this thread is a great guide, and thanks again.

Regards :)
 

·
Registered
Joined
·
40 Posts
Digging up an old one here. This is a job I've been meaning to do for a long time as the crack on mine had gone from one side of the area to the other. Melbourne lock down has been a great time to get this done.

The instructions were great and I did things slightly differently, that others may find useful if they decide to tackle this. I'd say overall it took me longer than quoted but that's just me and I wasn't really in a hurry.

  1. To bend the 20mm SHS to shape instead of bending it over a couple of bits of wood I held it in place against the door, marked approximate locations of where I thought it needed to bend. I then cut through 3 sides of the SHS with a thin cut-off wheel on the angle grinder. It was then easy to bend to shape. I then welded the SHS back together again, bearing in mind that as the welds cools and shrinks it will increase the bend so try and allow for this as best you can.
  2. You can probably get away without adding the 2mm and 3mm packing pieces although I'd at least add the 3mm as it adds a lot of strength and that's what we are trying to achieve here.
  3. I found it difficult to pack it out and get it into position inside the door exactly where it needed to go so I used a couple of the holes you drill at the top and bottom to put metal screws through the SHS and pull it into position. I then tack welded the other holes, removed the screws and welded up those ones.
  4. A Dremel tool, if you've got access to one, is very handy to tidy up after welding, especially if you also weld the original crack as I did. The grinder with a flap disk gets you most of the way but the Dremel does the finishing touches.
  5. I found that when I went to put the vertical plastic trim back up the side of the door that the bottom clip wouldn't go in because the SHS was now in the way. Once again I used the Dremel tool with a carbide cutter to put a slot in it.
  6. I also discovered that the wiring and plug for the stop light wouldn't go back through the hole due the SHS. I just cut it off, fed it through, and soldered it back together.
  7. It pays to also check inside the bottom of the door. I had lots of metal shavings from drilling and grinding. You really don't want to leave them in there. Best way I found to get them out was a magnetised screwdriver, the vacuum wouldn't fit.

All up I'm happy I finally did this. The door is now so much easier to open and close and I don't cringe watching a crack open up and the door flex every time you use the door. I still have to do the top coat but that's a job for another day.

Outerwear Metal
Outerwear Textile Metal
Vehicle Car Vehicle door Automotive exterior Auto part
Vehicle door Automotive exterior Vehicle Auto part Fender
Vehicle door Vehicle Room Automotive exterior Car
 
1 - 7 of 7 Posts
Top