Author Topic: Cutting rust out of a 1971 Eldorado Convertible  (Read 831 times)

Offline The Tassie Devil(le)

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Cutting rust out of a 1971 Eldorado Convertible
« on: March 01, 2017, 05:42:42 AM »
G'day all,

Finally started on the rust-removal in the floor of a 1971 Eldorado Convertible that belongs to a friend.   What looked like a good car, that had been rust-proofed before it left USA showed up as a disaster when the owner decided to have the interior completely reupholstered.

Everything was stripped out of the interior, that is seats, rear quarter and door trims, but left the carpet on the floor, before deciding to replace that as well.

As soon as he pulled the carpet up, I had received three texts on my mobile phone when I turned it on (don't have it on when at home).   Upon contacting him, I heard the sad news that he needed assistance, and required my services.

Below are some pictures of what I saw.

Turns out that the underside of the front floor was not rusty, except from where the holes were, as the floor had rusted from the top-side down.   Looks like the carpet had become wet, and stayed wet, quietly rusting away.

The rear floor had been repaired before, and boy, was it a crappy job, and would be tackled after doing the front, tidying everything up.

When I drilled out the spot welds, and removed the original floor, I couldn't believe just how good the under-floor bracing and the side sills were.   There were a couple of rust spots visible in the firewall panel, and these would be tackled before the actual flooring.   Got to have a good solid base.

More to come tomorrow.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #1 on: March 01, 2017, 06:25:32 PM »
Next comes the repair of the passenger side firewall section.

Close inspection revealed the need for a larger patch than first thought, so removing the affected section.

I am using 1.2mm steel, which is a lot stronger than the original.

To replicate the strengthening grooves, I made up a former out of strong steel, and rod spaced at the correct intervals, and placing the panel on top of the lower part, then belted the top part onto the panel to create the nice forming.   Pity all this will be covered with sound-deadening, and a coating of rust proofing underneath as it does look pretty if I do say so myself.

The holes in the panel are necessary to place plug welds through the panel, into the subframing.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #2 on: March 02, 2017, 04:36:53 PM »
Next comes the drivers' side under the brake pedal.

It is surprising just how much metal has to be removed to get back to the original thicker stuff.

Plus, not forgetting that one needs room to get in there with the steering column in the way.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #3 on: March 02, 2017, 04:57:01 PM »
Now comes the main front floor piece.   

I had tried to construct the piece in one, from side to side, but found it difficult to get it perfect with such a large piece, and working alone, it became to hard to handle, so I divided it up into three pieces.   Two sides, and one centre piece.

Using basic tools, lumps of steel, clamps, hammers, snips and pliers, one is able to bend anything into any shape required.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #4 on: March 02, 2017, 05:29:18 PM »
Once the side pieces were welded in place, then came the centre piece to complete the, what I thought was going to be, the hardest part of the job.

After cutting off the ends of the piece I had already bent up for the main piece, I continued to fold the back edge into place, and before trimming the ends to length, I had to replicate the creases to stop drumming, and create a stronger plane so people could stand on it without flexing.

This involved fabricating up another male and female mould out of more "scrap" that I had saved for that rainy day, that eventually comes.

Placing the panel between the two pieces of forming steel, and belting it with a 14 Lb sledge hammer does wonders, and makes things look factory stock.   Each pair of creases took at least four hits.  The secret is to have a solid backing, heavy steel, and a helper (the wife this time), and a good pair of ear muffs, as this process is noisy.

One must remember when cutting anything out, to look for fittings underneath as the pieces are removed, and this included the parking brake cable support that is under the drivers' foot.   This was removed, and welded into place before putting the floor into position.

The really good part of this little piece was that it makes a beautiful grounding clamp position, keeping the grounding wire out of the way.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #5 on: March 02, 2017, 05:46:52 PM »
Now that the front is completed, apart for general cleaning up and preparing for paint, time to tackle the rear.

The rear, I thought would be a simple remove the crappy previously patched areas, and weld in nice new steel, but boy, was I in for a shock.

Pulling up the screwed-in piece on the right side, I found a horrible sight.

Some disgusting patching had been done prior to it departing USA, and all I can say is that heads should roll for what they did.   

Prizing up the screwed-down steel, turned out to be a simple task as it was paper-thin aluminium, and it simply tore off in pieces as the screws weren't holding anything as the underside had rusted further.

This revealed a thin smear of some sort of filler that had been nicely cleaned off underneath to resemble a plain patch panel, and everything covered up with rust-proofing paint.   As can be seen from on top, everything was rusted, and required a much larger hole to fill.

BUT, I was further surprised to find that the sub structure was still perfectly sound, and therefore, after cleaning everything up, I was now ready to create another, but more complicated, patch panel.

More to come shortly as I start making this panel, and then revealing what is on the other side.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline Jeff Rose CLC #28373

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #6 on: March 02, 2017, 06:51:47 PM »
Jeepers....
I have a couple of spots on my rear fender that I need to do and I am afraid to tackle it. You are braver than me, that's for sure.
Good job,
Jeff
Jeff
CLC #28373
1970 Coupe DeVille
1955 Series 62

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #7 on: March 02, 2017, 09:08:28 PM »
G'day Jeff,

I don't think it is a matter of being brave, just that nobody else wanted to tackle the job, and there were various suggestions from covering everything with fibreglass and just patching what was there.

I should have been vary wary of this car right from the start, as when I rebuilt the engine, after the owner ran it dry because of a leaking water pump, and totally cooked the engine until it seized.

Whilst rebuilding the engine, it was found that there was a '75 120cc head on one side, and a '71 76 cc head on the other side.   No wonder it was impossible to tune.

The heads couldn't have been swapped at my reconditioning shop here in Tasmania, as the chances of getting two Cadillac engines in there at one time would be virtually impossible.   Getting one every two years would be remarkable as well.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline Jeff Rose CLC #28373

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  • Name: Jeff Rose
Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #8 on: March 04, 2017, 12:28:27 AM »
Ive probably done more than the average owner---but certainly not more than you guys. I have just never done any metalwork. I would like to try some day tho.
Jeff
Jeff
CLC #28373
1970 Coupe DeVille
1955 Series 62

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #9 on: March 04, 2017, 04:42:37 AM »
Continuing with the rear floor, the drivers side was actually a lot worse than the passengers side.

But, I am getting ahead of myself.

Seeing as I was going to be making two opposing patches, I made up the right side first, measuring, cutting oversize, bending and shaping before trimming to actual size.

Firstly, I made up a simple buck to replicate the first shape that had to be made, and once the metal was folded where necessary, I clamped it to the aforementioned buck.   Applying heat to allow me to create the right shape, I hammered it into position to follow the shape of the buck.

Than more measuring and bending over another former, this time made out of a couple of pieces of wood, with a tube clamped to the side, I manually rolled the metal into shape.

Further trimming etc, I tried to create the complex inner rear form with the original piece, but found it necessary to change tack and cut out another piece to manually shape, and oxy weld to the main piece.   This made the final piece a lot neater as well.

Bruce. >:D

'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #10 on: March 04, 2017, 05:00:13 AM »
This piece was then tacked into position, and taken to the bench for completing the welding, and back to the car a couple of times for checking that everything was not moving.

This piece was then roughly trimmed to size, and as I had to make another one, but completely opposite, I used the first one to shape the second one, but the opposite bending, etc.   Plus, as the hole on the Left side was larger than the right, I had to allow for the increase.

This also meant that in the trimming of the hole, I had to remove the Seat Belt Mounting bracket, which will be replaced when the patch is completed.

If one looks closely at the last picture, notice the two silver crescent things on the front edge?

These are very strong magnets that I use for holding steel into position when required.   They have a remarkable magnetic ability, and come out of Computer Drives, as in CD Burners and the like.   When trying to pull them apart, one has to be extremely careful not to get ones' fingers caught between them as they DO hurt.

I tacked both into position tonight, and tomorrow, I attack them to complete the welding.

Bruce >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline Rob Troxel

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #11 on: March 05, 2017, 09:31:59 AM »
You deserve a trip to the Drunken Admiral after all this work!

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #12 on: March 05, 2017, 05:20:59 PM »
Been there twice over the years.   When did you go there?

But, it will have to wait, as I now am about to attack the area under the back seat?   Heaven knows how it got this bad.   Must have been submerged, as the rusting, apart from a couple of spots, above the Exhaust pipe, has been from the inside out.   At least the subframing is good.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #13 on: March 13, 2017, 04:24:05 AM »
Completing the rear floor required the re-installation of the front left inner seat belt mounting point, which necessitated the drilling of holes for the bolt itself, and the spot welding points, then completing the welding around the rear pans.

Next task was the area under the back seat.   There were only three small patches there, but with a bit of poking around, I located many more "soft" spots, so the decision was made to continue in this area.

Turns out that it needed a virtual total replacement, as it was really bad.   

This time, I decided to change tack, and like the front, instead of one piece of steel, I used three.   Two small pieces on each side, and a larger one in the centre.

And again, I changed manufacturing the parts by making the patterns prior to cutting anything away.   This allowed me to be far more precise with the awkward folds and bends in the sides, as these were a lot different to the fore-done parts.   Plus, I could actually shape them almost to perfection, before cutting out the rust, and with leaving the new stuff oversize, it was easier to trim them to size before fitting.

Using the remaining centre section as a guide, made placement ideal.   Plus, as both left and right were the same, but opposite, I could make both pieces to fit the same.

After trimming and tacking into place, it was time to complete the welding before moving to the centre, and last piece.

Bruce. >:D



 
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #14 on: March 13, 2017, 04:36:59 AM »
Completing the side pieces then allowed the removal of the centre section, and the making of the new patch.

Using a pair of 1/2" UNC bolts in the seat belt holes allowed me to have some permanent locating points, until I was ready for the final tacking into place, before final trimming whilst welding.

The last three pictures show the cleaned up areas before covering everything up with Seam Sealer, and Body Dampening material.   It is a pity to cover everything up, but such is the joys of working with steel.   At least a run-over pedestrian won't get cut badly through striking rusty metal.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #15 on: March 13, 2017, 04:49:04 AM »
The final pieces that had to be made were the lugs to hold the wiring loom into place along the left side.

There needed to be four of these things made as the originals were either rusted, or had been so poorly reattached from prior repairs, that they were plain ugly.

Here I used a pair of tin snips and a edging machine to fold the edges to try and match the original.

These were then cleaned up of sharp edges, and welded to the places under the rear seat base, and floor to protect the wiring loom by keeping it securely held in position.

One thing that I have learned from this whole task is that by making my own sections, is that with a few basic tools, anything can be accomplished.   I was fortunate that I had sufficient tools to complete the task, and it is surprising what can be done with a 14 Lb Sledge Hammer, down to the simplest magnet.

Would I do it again?   I will need a rest first.

Bruce. 
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #16 on: March 14, 2017, 07:05:49 PM »
Well, the time has come to pack away all the tools that I used, but first, I thought it best I show what I actually used to complete the task.   I have neglected to show the trolley jack and the four extra Jack Stands, as they are still under the car.

Looking back, yes, this job isn't for the tool-less person, and as we down here don't have places where one can hire tools, I have had to buy a bit over the past 50 years, and I am glad I did.

I calculated the actual hours it took, and so far have come up with 93.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline boseephuss

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  • Name: Justin S
Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #17 on: May 22, 2017, 04:35:33 PM »
Excellent work!  Did you have to replace anything in the boot?  I am afraid that is the only area that needs attention on mine...
J. Sims
CLC Member #48960216

Offline The Tassie Devil(le)

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Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #18 on: May 22, 2017, 08:21:04 PM »
G'day Justin,

Surprisingly, the boot was good.   Underneath, the car was virtually rust free, so all the problems to the interior came from soaked seats, carpet, etc.

My summations of the car was that it had sat out in the weather for many years, whilst in USA, was brought back to life with some dubious quickie repairs, including a quickie re-upholstery job in vinyl, and a repaint, and then sent to Australia.

Even when I got the job to rebuild the engine, because the owner had boiled it dry, due to a collapsed water pump, and didn't realise it because none of the dash lights were working.   Yes, it seized.   I found that some time previously it had been fitted with a 120cc head on one side and the original 76cc head on the other.

Bruce. >:D
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'55 Buick Special Post Coupe (LHD)
'74 Chris Craft Gull Wing RHH
(Past President Modified Chapter)

Offline Caddy41

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  • Name: Doug Charter
Re: Cutting rust out of a 1971 Eldorado Convertible
« Reply #19 on: May 31, 2017, 06:57:18 PM »
Hi  Bruce..The average Joe wouldn't have a clue whats involved doing this type of fabrication..I've done it for a considerable part of my life and trying to get paid sometimes make think is it worth the effort...sometimes I've started to do a minor floor rust repair and finished replacing the whole floor pan..firewall to trunk......