Old patrol roof rust repairs

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:
Attachment 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:
Attachment 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
Attachment 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:
Attachment 80541

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

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

This is what I'm left with:
Attachment 80537
Attachment 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

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

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.

Quote:

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Originally Posted by 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 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!

Made some progress on the patrol over the weekend.

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

Attachment 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:
Attachment 80592

How this side of the thing looks overall:
Attachment 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)

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:
Attachment 80667

Clamp it in place:
Attachment 80668

Tack it in:
Attachment 80669

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

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

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

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

Stand back and stare at it:
Attachment 80674

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

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

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.

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

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.

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

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.

Got some more done:

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

Chopped a rusty bit out of the B-Pillar:
Attachment 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:
Attachment 80710

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

Finished welding and started grinding:
Attachment 80712

Gave it a shot of primer:
Attachment 80713

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

Chopped out and ground the paint off the edges:
Attachment 80715

Apply some dodgy bending methodology:
Attachment 80716

Tack it in place:
Attachment 80717

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

Go nuts with the flap disk:
Attachment 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!

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:
Attachment 80844

Tacked in:
Attachment 80845
Attachment 80846

Welding up:
Attachment 80847

Welded up:
Attachment 80848

Flatteneing off:
Attachment 80849

Then rinse and repeat with another patch:
Attachment 80850
Attachment 80851
Attachment 80852
Attachment 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.

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:
Attachment 81021

cut out and bent up some patch plates:
Attachment 81022

Spent an afternoon playing metal tetris:
Attachment 81023

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

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

A problem easily solved with the air body saw...
Attachment 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):
Attachment 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.

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

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

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

Sand it back and drill some holes in it for plug welds (I did paint the back of it with weld-thru primer):
Attachment 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:
Attachment 81039

Weld it up, then grind it back:
Attachment 81040

Give it a coat of weld-thru primer:
Attachment 81041

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

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

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

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

You have the patience of a saint. Top work.

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)

Quote:

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Originally Posted by PureCaboose

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.

Finished welding in and grinding back a patch:
Attachment 81066

Complete with some primer:
Attachment 81067

Marked out some steel:
Attachment 81068

Then chopped it up:
Attachment 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:
Attachment 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...
Attachment 81071

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

You are amazing, brilliant work, top stuff

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

Welded in some temporary support struts:
Attachment 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:
Attachment 81083

Marked out the cut on the rear:
Attachment 81084

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

Test fitted the gutter I fabricated earlier:
Attachment 81087

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

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

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...
Attachment 81549

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

Do a bunch of fiddly welding to rebuild the edge piece:
Attachment 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):
Attachment 81552

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

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

Weld everything up:
Attachment 81555

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

Hide all that with some primer:
Attachment 81557

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

Some more welding...
Attachment 81560

Add some primer:
Attachment 81561

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

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

Made up a patch using a paper template:
Attachment 81573

Tacked in place:
Attachment 81574

Welded in:
Attachment 81575

Hit with the grindy tools:
Attachment 81576

Quick squirt of weld-thr:
Attachment 81577

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

Weld in the first patch:
Attachment 81579

Grind it flush:
Attachment 81580

Stick the second patch over the top:
Attachment 81581

Weld it in:
Attachment 81582

Grind it back:
Attachment 81583

Apply paint:
Attachment 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.

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

Fabricate the last piece that fits at the front:
Attachment 81639

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

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

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

Gutter attached:
Attachment 81643

I admire your skills and patience :clapping:

Looking good.

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...
Attachment 81780

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

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

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

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.

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

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:
Attachment 81880

Started chopping some of the gutter out:
Attachment 81881

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

Stripped off the rusted mess that was once the passenger side gutter:
Attachment 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:
Attachment 81884

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

Got the passenger side finished off.

Started with this:
Attachment 82093

Cut out some steel sections
Attachment 82086

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

Ended up with three of these:
Attachment 82088

Welded them end to end and test fitted:
Attachment 82089

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

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

All welded up:
Attachment 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:
Attachment 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.

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:
Attachment 82928

Flipped the roof over:
Attachment 82929

Started tacking:
Attachment 82930

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

Gave it a whack of etch primer:
Attachment 82932

Chopped all this rusty junk off the edges:
Attachment 82933

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

Last patch going in to the roof support frame:
Attachment 82935

All coated in rustkill paint:
Attachment 82936
Attachment 82937

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

Plug welded both ends in:
Attachment 82940

Gave it the usual rustkill treatment:
Attachment 82941

Left it to dry for a few hours, then dropped the roof on top:
Attachment 82942
Attachment 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:
Attachment 82944

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

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

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.

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.

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: