Old patrol roof rust repairs

[Nhoward]

After enjoying my patrol for a few months, I started to notice the dreaded rust bubbles appearing on the outside of the 4x4, along with random flakes of rust falling on me while I was driving.
This is what it looked like from the outside:
80531

I pulled the headliner and everything looked fine.
I used an inspection mirror to see down into the gap between the roof skin and the frame. Not even close to fine .
I made the mistake of poking at a few places with a screwdriver, and found a few places where someone had managed to make rust and filler take on the appearance of metal.

I started cutting some of it out with an air body saw:
80540

After seeing that mess, and what I saw with the inspection mirror, I decided that if I was going to fix this properly, the whole roof skin would have to come off.

I started the process:
Removed the windscreen
80534

Used a stripping disk to clean all the seam sealer and it's underlying layer of rust out of the gutters
Ground back the paint on all four corners to find the brazing line where the roof is attached to the pillers
Cut through the roof skin above the brazing line with a combination of air body saw and angle grinder
Removed the chunk of hillman hunter bonnet that the previous owner had pop-riveted over the very rusty sunroof
Removed the sunroof assembly
Went nuts with a spot weld removal drill bit - there are a lot of spot welds so this took me about a day of drilling

spot welds around the windscreen drilled out:
80541

Once all the welds were gone, I stood on the back seat and shoved the roof skin upwards and backwards:
80542

Took the whole skin off and stuck it on the lawn:
80539

This is what I'm left with:
80537
80538

A bit of a mess.

The plan from here:
- Weld in some temporary bracing
- Drill out spot welds and remove roof superstructure
- Strip off gutters
- Chop out all the rusty bits from the frame and weld in steel patches
- Fabricate some new gutters and weld them on to the frame
- Weld the roof superstructure back on
- Remove temporary bracing
- Chop out all the rust bits from the roof skin and weld in patches
- Weld the roof skin back on
- Drench everything in rust proofing
- Paint the outside of the thing

[0-TJ-0]

Looks like a big job! Glad it's you and not me. Good project though.

[Rossco]

Amazing work mate. My GQ had the dreaded roof rust, after doing one semi-dodgy repair and having it rear its head again with vengeance ended up getting a new shell and doing a cab swap. Once it starts poping up on the outside you know it's pretty bad in there. . . Good luck looks like fun can't wait to see how it comes up.

[Nhoward]

Amazing work mate. My GQ had the dreaded roof rust, after doing one semi-dodgy repair and having it rear its head again with vengeance ended up getting a new shell and doing a cab swap. Once it starts popping up on the outside you know it's pretty bad in there. . . Good luck looks like fun can't wait to see how it comes up.

I toyed with the idea of swapping the shell or grafting on a donor roof, but I have very little chance of finding either in good condition over here in NZ. Our humid climate and day/night temperature swings are excellent at causing the condensation that causes these 4x4s to rust from the inside out.

Many of the issues I am dealing with are as a result of dodgy repairs that were done to get the thing through it's next inspection - steel patches welded in with no rust proofing, RTV sealant masquerading as a roof gutter etc.

I payed $1000 for the patrol, so I had some idea what I was getting in to. I figure it doesn't really owe me anything, and worse case scenario I have to scrap it after I have learned a whole bunch about doing bodywork on a 4x4.
Best case scenario I fix all the rust and drive the thing for several more years.

I'll update this thread as I continue to hack away at the thing. Fortunately I have a MIG, an air body saw, and an angle grinder - and I'm not afraid to use them!

[Nhoward]

Made some progress on the patrol over the weekend.

Out came the air saw, and off came large chunks of bodywork:
80590

80591

The Headliner support brackets were removed, more rusty bits chopped out, rear window removed, all edges ground back with a stripping disk, and the inside of the frame rails coated with rust kill epoxy primer.
The edges where I will be welding new steel in got a shot of weld-through primer instead of the epoxy stuff. All the cavities will have cavity wax injected when I'm done with the welding bits:
80592

How this side of the thing looks overall:
80593

Still quite a bit of rust on this side, but I want to get some new steel welded in around the B pillar area before I go chopping any more bits out (I don't want the body getting twisty on me)

[Nhoward]

Got a bit more done today. Nice to be putting metal back into the patrol for a change.

Cut out, bend up and prime some sheet metal:
80667

Clamp it in place:
80668

Tack it in:
80669

Mark out a big chunk, then cut it out:
80670

Bend it with clamps, hammers and a chunk of angle iron, then tack it in place:
80671

Weld er' up (did some grinding as I went):
80672

Paint it (weld-thru primer on the area the gutters will attach to, etch primer on the rest):
80673

Stand back and stare at it:
80674

One small part of a very big job with tons left to do, but it's progress in the right direction.

[PeeBee]

Clever guy, watching this with interest, thanks for the detailed posts and 'how to' ideas.

[MudRunnerTD]

Yeah wow! Big Task. Great Effort mate. I will watch with interest. Why have you left the seats in mate? Surely they are going to get weld splatter and be wrecked during this resurrection.

[MudRunnerTD]

What panel steel are you using? Have you got a Donor Bonnet or something? Are. you using a bender or just hand shaping?

[MudRunnerTD]

Ghee, a Donor car would be bloody handy here though. something that is wrecked that you can cut out those roof mounts would be sik. Chat with your local wrecker, he might have something that is fully stripped that he is looking to crush or send to smelter that you can cut a heap out of. Nice work mate.

[Deano2506]

Best post I've seen on here in a long time.great looking work too.
Keep up the updates mate

[Nhoward]

Figured I would answer some of the questions you guys are asking...

I left the seats in because they are already rather tired/stained/ratty so I'm not worried about the odd burn mark (and I don't currently have anywhere else to put them)
I am however protecting the interior from weld splatter as best I can using a mixture of wet old bedsheets and spare steel panels that I wedge between what I'm welding and the interior.

I'm using the side panels from some server racks that we decommissioned at work as the donor steel. It's the right thickness and I have a pile of them.
I'm hand shaping the steel at the moment - lacking a sheet metal bender I'm afraid. The usual process is to clamp the steel to a large chunk of angle iron, then bash it with a hammer until it looks about right.

A donor car would be handy to chop bits out of, however finding one without any rust in the roof would be tricky. All the patrols I have seen at wreckers have visible rust in the roof area, and even if I find one without visible rust, I won't know its condition until I haul it home and yank the roof skin off. At this juncture, I think it's a better/easier option to just fix the rust in what I've got.

At this point it's unfortunately a slow project. I can only really work on it during the day on weekends, when it's not raining, and at reasonable times so I don't drive my neighbours insane with the dulcet tones of air compressors, saws and grinders.

[Nhoward]

Got some more done:

Cleaned up this bit where the frame had rusted out:
80708

Chopped a rusty bit out of the B-Pillar:
80709

measured up and chopped off a piece of server panel that had a convenient 100* bend in it and tacked it in to place:
80710

Started welding it up. Doing a little bit at a time so that nothing gets too badly warped:
80711

Finished welding and started grinding:
80712

Gave it a shot of primer:
80713

On to that hole in the B-pillar.
One CAD template transferred to steel:
80714

Chopped out and ground the paint off the edges:
80715

Apply some dodgy bending methodology:
80716

Tack it in place:
80717

Finesse it with a large hammer, and weld it in:
80718

Go nuts with the flap disk:
80719

Not bad for a Saturday afternoon. Once piece at a time.
With the country going in to covid19 lockdown on Wednesday, the upside may well be more time to work on this thing!

[Nhoward]

I'm trying to be nice to the neighbors during lockdown, so I have not been working on the Patrol much.
I have made a bit of progress though;

A couple of patches coated in weld-thru primer drying in the sun:
80844

Tacked in:
80845
80846

Welding up:
80847

Welded up:
80848

Flatteneing off:
80849

Then rinse and repeat with another patch:
80850
80851
80852
80853

At this point I was rapidly running out of daylight so I called it a night.

Progress is still slow, but the driver's side of the truck is now more metal than rust and air.

[Nhoward]

between the covid lockdown and a few weeks of bad weather I have not managed to get too much done, but I have made some progress;

Chopped out a big chunk around the B-pillar:
81021

cut out and bent up some patch plates:
81022

Spent an afternoon playing metal tetris:
81023

Got it all welded in (and most of it ground back & painted):
81024

On to the next problem... quite a bit of rust on the A-pillar:
81025

A problem easily solved with the air body saw...
81026

That did leave quite a bit, oddly shaped hole though :jawdrop:

For my next challenge, I need to make the piece on the left look like the one on the right (minus the rust):
81027

While I was tearing some of that apart it did make me wonder - do any of you lot know why the roof skin and gutters are brazed on at the corners?
I'm hoping it was done for ease/speed of assembly but I'm not 100% sure.

[Nhoward]

Right... time to something about that hole...

Use some paper to make a template, then trace the result on to some steel:
81036

Cut it out, stuck it in a bender then bash it with a hammer (or 3):
81037

Sand it back and drill some holes in it for plug welds (I did paint the back of it with weld-thru primer):
81038

Weld in the plug welds, tack some of it place then align it to final shape by bashing it with a hammer some more:
81039

Weld it up, then grind it back:
81040

Give it a coat of weld-thru primer:
81041

Got this other patch tacked in, then ran out of daylight:
81042

I'm getting tantalizingly close to finishing off this frame rail.

[Rossco]

Love your work mate keep it com'n. She's looking good can't wait to see how it comes up [emoji106]

Sent from my SM-G930F using Tapatalk

[Plasnart]

Yep this is a bloody tops thread. Loving it Nhoward Brilliant work so far mate, keep it going.

[mudnut]

You have the patience of a saint. Top work.

[PureCaboose]

I love your work, I am so limited in what I can do in my workshop at the moment due to all the joeys in care...can't even finish putting the engine back together.

Great to see someone repairing rather than just throwing away a lovely old truck.

It's amazing how much time we don't have when in quarantine (not that it changed anything for us, if anything we go out more. sigh)

[Nhoward]

It's amazing how much time we don't have when in quarantine (not that it changed anything for us, if anything we go out more. sigh)

Yup... I work in IT so I am able to work from home pretty easily. Combine that with a senior management team that are bored senseless as a result of the lockdown, and it's very easy to get buried in more work than you would have otherwise.

[Nhoward]

Finished welding in and grinding back a patch:
81066

Complete with some primer:
81067

Marked out some steel:
81068

Then chopped it up:
81069

I did three of these in total, then ran them through the bender and welded them end to end.
The end result is too long to easily take a photo of, but it should be welded to the side of the frame rail in due course.

Cleaned up the rear of the thing - removed what remained of the rear gutter and marked out the bit I need to cut out and patch:
81072

I ground off the rust in the good areas and gave them a shot of primer, but it was too dark to get a good photo.

The next task is the back corner. A bit rusty...
81071

I'll have to fabricate and weld in a temporary support for the roof frame before I chop that lot out.

[PeeBee]

You are amazing, brilliant work, top stuff

[Nhoward]

Time to do something about the rear right corner of this thing...

Welded in some temporary support struts:
81082

Removed the rusted bit of the existing support, removed the remains of the gutter and marked out the intended path of the body saw:
81083

Marked out the cut on the rear:
81084

A few moments with the body saw... no more rust, but some big holes to patch:
81085
81086

Test fitted the gutter I fabricated earlier:
81087

Needs to be another 250mm longer, but looks like it'll work.

[oxmann]

How is your project coming along ? would love to see some more updates.I have just started doing this to my "92 GQ patrol" not as bad as yours, but still needs doing....and your pics,ideas etc are excellent.I see you are in NZ as I am,where abouts ?? Anyway thanks for your project updates,would love to see some more....cheers

[Nhoward]

Unfortunately life and Auckland weather have been getting in the way as of late, but I have managed to get a bit more done:

Time to do something about this oddly shaped hole where the A-Pillar connects to the roof frame...
81549

Cut up some patch plates and give them a shot of weld-thru:
81550

Do a bunch of fiddly welding to rebuild the edge piece:
81551

Weld in the first part of the patch (had to call it a day at this point so I just fired some primer over it):
81552

Picking up where I left off, grind back the primer etc. and get ready for more patching:
81553

In with the next patch. This area has a join between panels, so I replicated that with my repair (overlap & plug welds):
81554

Weld everything up:
81555

Apply the finger sander, angle grinder and die grinder:
81556

Hide all that with some primer:
81557

That's all the rust in the driver's door are repaired, on to the rear end.
Tack in the patches:
81558
81559

Some more welding...
81560

Add some primer:
81561

Just need to finish off the back right corner, then the drivers side frame repairs will be complete.

[Nhoward]

Got this weirdly shaped rusty area on the right rear corner to sort out:
81572

Made up a patch using a paper template:
81573

Tacked in place:
81574

Welded in:
81575

Hit with the grindy tools:
81576

Quick squirt of weld-thr:
81577

Now for this one... As it was originally where two panels overlap and join, this was a little more complicated.
81578

Weld in the first patch:
81579

Grind it flush:
81580

Stick the second patch over the top:
81581

Weld it in:
81582

Grind it back:
81583

Apply paint:
81584

With this bit done, I can now say that the driver's side roof frame is rust free!

Next is to fabricate and weld on a new gutter, then do something about the roof support framework that is currently hanging mid-air.

[Nhoward]

Managed to get the driver's side gutter completed and on the truck.

Fabricate the last piece that fits at the front:
81639

Weld it on the bit I made earlier, grind it back and paint it:
81640

Spend quite a long time doing many, many plug welds:
81641

Almost there (welding up the front at this point)
81642

Gutter attached:
81643

[TimE]

I admire your skills and patience :clapping:

[mudnut]

Looking good.

[Nhoward]

Got a bit more done on this project.
Unfortunately I was rushing against an incoming storm so I did not take too many photos.

Mark out some steel that will become the end of the roof frame support...
81780

Use a combination of a sheet metal bender and some hammers to fold it up
81781

All three bits welded in and primed - the roof frame is no longer hanging in mid-air.
81782

With that, the driver's side is done! Now to do the same process on the other side...

[Nhoward]

I'll mention the photo makes it obvious why these vehicles rust from the inside out.

the roof is attached to the top of the gutter, leaving a void between the roof skin and the roof frame for moisture to accumulate.
The rust proofing in this area also appears to be sub optimal - paint does not seem to make it down in to the void during manufacture, so we are just left with the phosphate coating to protect the underlying steel.

My current theory on the corrosion is condensation forms on the inside of the roof, runs down the inside and pools in the void, with nowhere to go.

In order to prevent the roof rusting out again any time soon, I am planning to insulate the inside of the roof skin with dynamat or similar, inject something like two-pack stone chip paint into the void between the frame and the roof skin, and drill some drainage holes in the gutter so that any moisture that accumulates has somewhere to escape.

[0-TJ-0]

Always happy when I see your thread pop up with a new update. Satisfying watching it come together mate, good job.

[Nhoward]

Had the first weekend with good weather in a while so I got the tools out and pressed on with the patrol repairs...

Started drilling out many spot welds holding the rusty gutter on:
81880

Started chopping some of the gutter out:
81881

Welded in some temporary supports for the roof frame, marked the ends of the roof frame that need to go, and started cutting:
81882

Stripped off the rusted mess that was once the passenger side gutter:
81883

Hauled out the old oxy-acetalyne rig and used that to get the old braze off the corners.
Kind of scary holding the torch in one hand and the drill with the wire wheel in the other, and playing "dodge the flying molten metal" but it came up well:
81884

Went at what remained with the wire wheel, the stripping disk and the sanders:
81885

After that was done I gave the area a wipe down with some rust converter to catch anything I missed with the power tools and called it a day.

[Nhoward]

Got the passenger side finished off.

Started with this:
82093

Cut out some steel sections
82086

Persuaded them into the shape I wanted with this contraption (yes, that's a sheet metal folder clamped to my kitchen bench):
82087

Ended up with three of these:
82088

Welded them end to end and test fitted:
82089

Finished it off, drilled a bunch of holes and clamped it to the truck>
82090

Spent far too long making far too many plug welds:
82091

All welded up:
82092

Welded on some new roof frame support brackets I bent up, ground back all the welds and gave it a shot of rustkill paint:
82085

Now I have to sort out the not insubstantial rust in the roof support frame, then it's on to the roof skin itself.

[Nhoward]

I know it's been several months since I have updated this thread, but the project is still ongoing.

So... what have I been up to?


Welded up a ton of rivet holes on the sheet of steel that used to be over the sunroof:
82928

Flipped the roof over:
82929

Started tacking:
82930

Back over it goes to begin a very long, slow stitch welding job:
82931

Gave it a whack of etch primer:
82932

Chopped all this rusty junk off the edges:
82933

Ground off the last of the rust in the roof support frame:
82934

Last patch going in to the roof support frame:
82935

All coated in rustkill paint:
82936
82937

Started building this support to bridge the gap and reinforce the roof frame where the sunroof used to mount:
82938
82939

Plug welded both ends in:
82940

Gave it the usual rustkill treatment:
82941

Left it to dry for a few hours, then dropped the roof on top:
82942
82943

Next is the fun task of welding in strips on all sides to fill the air gap, then plug welding them to the gutters.

Also found this mess lurking under a tin's worth of filler:
82944

Should be straightforward after what I've done so far.

[PeeBee]

Was wondering where you have been? Great job, loving this build. Brilliant documentary also. thanks

[Plasnart]

Great to see you back NH. This is such a great thread, love your work mate! Can't get enough of skilled panel work and so well presented.

[MudRunnerTD]

Looking great mate. I too rebuilt a GQ in the back yard and used one of those White Tents. it got it done but loving a Shed now. I had the tent set up and the car fully prepped for paint. masked up and rubbed back, washed down with wax and grease remover and ready to go...... Got up at 7am the next morning for Paint and it was blowing a bloody gail from over the side fence and it got up and under the tent and destroyed it.... On Paint Day! Hours and Days of prep was gone. Was a very shit day. i was gutted. i could just sit and look at it.

Your project s coming up a treat mate. a Credit to you.

[Intrinsic]

I just bought a 1980 MQ that has what appears to be a couple small rust sections in the roof at the gutter line (as well as the door corners but that should be easy). I was thinking an easy fix, but after seeing what happened to this one I am dreeding to see what lurks behind. I can only hope that it is not as bad as that :1087:

[Nhoward]

I just bought a 1980 MQ that has what appears to be a couple small rust sections in the roof at the gutter line (as well as the door corners but that should be easy). I was thinking an easy fix, but after seeing what happened to this one I am dreeding to see what lurks behind. I can only hope that it is not as bad as that :1087:

You might be lucky and it is just surface rust, but if you can poke a screwdriver through it I'm afraid it has rusted from the inside out.
You'll have to pull the headliner and have a look in the cavity to be sure.
Best of luck!

[Nhoward]

Got a bit more done...

Clamped up the rear gutter section:
83038

Plug welded it in:
83039

Started on the first side piece...
Apply a bunch of clamps:
83040

Realise that due to sitting on your lawn for about a year, along with having bits chopped out and more bits welded in, the roof is not exactly the right shape, so persuade it with a strap:
83041

Apply many tacks:
83042

Spend a few hours stitch welding the whole lot (going slowly to minimise warping)
83043

Grind it all flush:
83044

Throw on some etch primer:
83045

Now I have to repeat that process until there is a new band of steel around the whole roof, fabricate the corner pieces, then plug weld the whole lot to the gutters and braze the corners.

[Rossco]

Bloody awesome work mate can't wait to see how she comes up [emoji106][emoji106]

Sent from my SM-G930F using Tapatalk

[Plasnart]

Nhoward how you going with this mate? So looking forwrd to seeing you finish this. So impressive.

[Sprock]

Bloody hell I just went right through this thread . Incredible 👍🏻

[Nhoward]

Unfortunately I have been rather busy with work/life in general so progress has been a bit slow (and there is a subdivision going in next door, with construction 6 days a week, so I am trying to not piss off the neighbors with my own power tools)
I have managed to get a bit more done though.

I have not taken as many photos this time, as it's the same procedure I used on the other side in the last post.

Setting up the left side for welding (with added strap persuasion and a ton of clamps):
83647
83648

After that came the usual deal - tack it in a bazillion places while shoving it this way and that to get the bits in alignment, then weld it all up:
83649

Did the same thing on the back:
83650

Also added some er... substantial... reinforcement to the long-suffering bunnings tent keeping the rain of the project as it was trying to take flight:
83651

Next step will be to fabricate the 4 corner pieces, then roof attachment time!

[Nhoward]

Well... MudRunnerTD called it - the tent got trashed.
A couple of months ago we had the worst storm of the year, and at about 4am the top of the tent took off into the night. I was up to my eyeballs in my day job, so I let the patrol sit under the tarp for a while. Shortly after that, delta hit our shores and it was back into lock down we went. What fun.

What was there before:
84373

What resulted after:
84372

Fortunately the tent had started leaking, so I was in the habit of keeping the patrol under a tarp inside the tent.

Right then... If I want to progress this thing I need some shelter since the weather is still garbage.
Fortunately I'm known amongst my friends as that guy that hoards random useful crap (I often get calls along the lines of "hey we are about to throw out <random stuff> do you want it?) end result - I had some timber laying around.

I added "vaguely sufficient carpentry" to my list of random skills and constructed this lot:
84379
84380

Excellent... somewhere dry to work, and with a much lower chance of it blowing away in the night.
84371

Right... now that I have somewhere dry to work, back to the patrol.

Fabricated what was the most irritating piece of metal in the whole project and started persuading it in to place:
84374

Welded it in:
84375

Fabricated the bit for the back right corner, then stuck that in:
84376

...and ground it back:
84377

Similar deal with the front left:
84378

Next up:
- Finish fabricating the piece for the back left corner
- Finish fabricating one tiny bit for the front right corner
- Pull the roof off again, clean up any of the welds that need it
- Prepare the corners with flux for brazing
- Final roof fit-up and far, far, far too many plug welds!

[Plasnart]

Far out mate, you have to be the clear leader for best first 25 posts in the history of this forum. Just love what you've done so far.

[Cremulator]

Far out mate, you have to be the clear leader for best first 25 posts in the history of this forum. Just love what you've done so far.I agree!
Congratulations, you can now download the manuals.
[emoji23]

[Rossco]

Yeah wow Kudos to a job done well, bloody amazing can't wait to see hire she comes up [emoji106][emoji106]

Sent from my SM-G781B using Tapatalk

[Nhoward]

Managed to get a whole lot done since the last update...

Fabricated this bit for the front left:
84399

Welded in:
84400

Fabricated this bit for the rear left and welded it in:
84401

Cut the last roof patch piece and tacked it in:
84402

Welded up and ground back:
84403

Propped the roof up to get better access to some bits at the edges I needed to weld:
84404

Clamped up the front of the roof to the windscreen frame, welded it in, then ground it back:
84405

Dropped the roof back down, and applied a ton of clamps and some straps:
84406

Commence far too many plug welds:
84407

End result: roof skin now bonded to body:
84408

[Cremulator]

Great job [emoji108]

[happygu]

Great job ... a looootttt of work, but so awesome to see it done at home with minimal tools and amenities

[Nhoward]

Got some more done on the patrol...

Dragged this thing out of the depths of my storage are:
84430

Did the flux/bronze/fire thing and brazed the corners on:
84431

Dressed the brazing and the plug welds from last time:
84432

Flooded the gutters with a couple of tubes of POR15 seam sealer/filler (also sealed the underside) :
84433

Once that lot cures, I have a couple of liters of cavity wax to blast in from the inside.

[budgie]

Hey mate great thread!

I will be starting my roof in the next month, although mine isn't as bad but i did find a whole roof that was cut at the pillars as a spare and will be replacing the whole roof skin as well as cutting sections out and using the spare panels i have!
i haven't had much time to strip my spare roof back Ive only stripped back the silicon in the gutters and rubbed the paint back where the brazing is.

couple quick ones for ya,
Q1 What size spot weld drill bit did you use? i bought a 6mm Sutton one but i think its to small maybe a 8 or 10mm might be better?
Q2 I noticed you got an oxy set up to melt away the bronze. i haven't even looked into a oxy set up so don't know the costs and if its worth it. maybe a small grinder might work?
Q3 Also why did you bronze the corners like they are originally in your last post and just not mig them up?

Ill most likely have more questions later on haha but don't want to pester you with a whole bunch!

Good thread its defiantly giving me more courage to do mine and although mine is my daily i have some time over xmas to do it so hopfully i can get it done!

Cheers,
budgie