PDA

View Full Version : GU Patrol Barn Door crack repair guide



mudski
3rd June 2014, 10:24 AM
O.k So I have had a crack in my right barn door since owning the car. For those who don't know, the crack is caused by hanging a larger than stock tyre from the door bracket. The heavy tyre tries to pull the door outwards, hence, the window frame flexes just above where the frame meets the door skin and eventually cracks. Mine was cracked around half way through and hadn't moved, until I hung a 35 off it and it instantly cracked further. So something had to be done. Upon removing the inside door trim I had discovered that it was cracking on the inside too.
4530845309

I hunted around for a second hand door with no crack and the best I came up with was $400. No guarantees this door won't crack too...So I bought a Cigweld Gas/Gasless 130Amp mig welder for $350 and I will have this for other projects too...

So gents here is how I went about repairing the crack. I am no expert welder and body repairer to I bloody hope it stays together.
In a nutshell, I curved and slid up the inside of the door skin the RHS and plug welded it to the door...

Tools you will need....

Mig welder
25x25 RHS about 400mm long
3mm x 25mm'ish flat steel about 800mm long
A Hydraulic press to bend the RHS or something else to do the bending
Drill and drill bits
Grinder and flappy disc to sand back the paint on the area to be repaired
Body filler
Spray putty / Primer
Paint
Plenty of time and patience
Welding skills, which I don't have
Body repair skills, which I didn't have either, Lol.

Paint I used was just from SuperCheap. I gave them the paint code and they mixed up a spray can for me. I also got a can of clear for the final coat.
45316

1. Removal of parts


Inner door trimmings
wiper arm and motor
top locking mechanism and control rod
door catch
door opening handle and mech.
all wiring going up to the top of the door

2. Preparation

I went roughly 200mm either side of the crack and measured and marked it out on the door. Then proceeded to drill 8mm holes down the door staying in the 400mm length, on both corner edges of the door as you will only be able to weld to two sides of the RHS.

45310

3. Shaping the RHS

This was quite tricky and took a while to get right. Luckily I have a cheap 12ton press I bought and its been money well spent i tell you. I used the press to bend and shape the RHS to the curve of the door.
45311

To make the RHS nice and tight in the door I welded the flat steel to the side where I was to weld to basically pack it out. After I did that, I was fitting, removing, fitting and removing to still get the contours right. This take a few good hits with a hammer to slide it up the door skin, getting it out was not fun, I had to use a long bit of steel down from the top of the door where the top lock sits to punch it out... Grinding the edges off the flat to suit the contour of the RHS. Finnally the RHS was pretty close. Well good enough for me. Lol.

4531245313

This is what the RHS looks like up inside the door...
45315

4. The welding begins.

I forgot to take a pic of the finished welded door. Luckily I suppose as I as I ain't very good at welding. But all I did was slowly weld at the RHS and slowly filled the holes up with weld. Doing this slowly as I didn't want the door glass and rubber to get too hot. I had a wet rag with me and some water to pour over it just incase it got too hot. After a few welding sessions and then grinding sessions I thought it was good enough for me.
45314

Remember to mask up the back door glass, as I forgot and it copped a little grinding spray and pitted a small section of the glass. :(

5. Bog and sanding time.

This is another area where I don't shine but I had nothing to lose really and wasn't too concerned as you can see this section with the door shut. :)So the bog was applied, I waited for it to dry and sanded it back until I was happy with the result.Like my bog skills?
45317
One thing I found is I applied too much bog and didn't sand enough back. I had a though after I had painted it that there was too much bog over the cracked area and I knew the door would still flex a little. The end result was the bog cracked, so I just ran some white Sikaflex over it after the job was finished...

I forgot again to take a pic of my final sanding job put here is a pic of the final spray putty before I painted it...I did four fine coats of spray putty with a light sand in between....
45318

6. Final paint

I did around six very light coats with the paint, also with a light sand in between using 800grit sand paper. I could have used finer but thats all I had...
45319

Then four coats of clear to finish it off....

4532045321

Put all the hardware back in the door and then had beer!!! :bananarock:

Hope this helps other out with their repairs...

04OFF
3rd June 2014, 10:32 AM
Very nice job mate ! :bigthumbup:


Don't forget the paint or rustproofing on the "inside" where you worked.

mudski
3rd June 2014, 10:43 AM
Very nice job mate ! :bigthumbup:


Don't forget the paint or rustproofing on the "inside" where you worked.

I could only go as far as painting the back sides ( the unwelded sides) of the RHS as you have zero access in there once the RHS is in and welded up.

04OFF
3rd June 2014, 11:16 AM
Im thinking, if you had perfectly good door, you could use Sikaflex to attach the extra support inside , may be enough to prevent the flex and so crack in the first place ?

mudski
3rd June 2014, 11:44 AM
Yes you definitely could I reckon. Or even drill into the inside of the window frame ( under the trimming) and screw it in. But the RHS needs to go in super tight so theres no movement. Or very little movement.

megatexture
3rd June 2014, 10:45 PM
Nice job mate that looks good! You could Spray some penetrol up in there with a straw fitting, it will make a flexible airtight film to prevent rusting, great for hard to reach areas I love the stuff.

http://www.bunnings.com.au/flood-300g-penetrol-spraycan_p1560172

brimon
27th June 2014, 05:31 PM
Great post Mudski, I will be doing the same repair shortly. Do you believe that you have created enough strength for the door to carry a rim and 33" tyre, I'm going to try anyway but just thought I would get you opinion as I don't have the money to buy a wheel carrier and don't want the extra 100kg weight that comes with it either.

threedogs
27th June 2014, 05:35 PM
A 33" and rim would weigh around 40kg I would think , you could do what Ive done and mount the spare internally

mudski
27th June 2014, 05:39 PM
Great post Mudski, I will be doing the same repair shortly. Do you believe that you have created enough strength for the door to carry a rim and 33" tyre, I'm going to try anyway but just thought I would get you opinion as I don't have the money to buy a wheel carrier and don't want the extra 100kg weight that comes with it either.

Thanks....
I have a 35inch on the door and it's holding great.

Shaunyb
27th July 2014, 11:44 PM
did you disconnect the battery when welding? probably silly question

megatexture
28th July 2014, 12:06 PM
It seems like a standard practice, I always do IMO better to spend 5 mins doing that than having to replace the ecu or any other issue that could come up.

mudski
28th July 2014, 01:22 PM
did you disconnect the battery when welding? probably silly question

Not silly at all... But no I didn't. I totally forgot to be honest. Like Maga said its standard practice though.

Bulbous
2nd August 2014, 04:42 AM
Love you for this post - checked my barn door today and found a crack. Not as bad as yours but it's obviously on it way.

Thanks

Dananjen
1st January 2015, 04:19 PM
did you disconnect the battery when welding? probably silly question

Best idea is to disconnect the battery

kyle86
21st February 2015, 09:38 PM
Well done mate top job. Ill be using this one

growler2058
22nd February 2015, 02:02 PM
Cool I've also got a cracked door.
Because I'm picky I reckon by the look of it that's SHS not RHS but whatever hahahahahaha ;)

threedogs
22nd February 2015, 03:23 PM
@ Growler ,,,,Already,,,,, whats the history,,,,, as in previous owner???

Winnie
22nd February 2015, 08:15 PM
@ Growler ,,,,Already,,,,, whats the history,,,,, as in previous owner???

It was a mine vehicle, the thing is shagged!!!!

rluma
9th April 2015, 07:35 PM
Great Post, Out of interest - How long did you spend on it start to finish?

mudski
10th April 2015, 11:03 AM
I did it over a few days. The longest part was waiting for the undercoats and top coats to dry. The actual repair side took around three hours from memory.

ramma
16th May 2015, 04:52 PM
Hey was your door sqeaking and driving you crazy while driving around? I have a slight crack just under my window but its about 10mm long im going to have to do this mod or get another door I think

bigguwesty
1st January 2016, 12:04 PM
Unfortunately I'm doing this I've just found..