Bodywork Quality 1950-1970

[Lester H]

This will have been asked before and it’s a bit of a ‘pub bore’ topic, but was thicker steel used in everyday family cars on sale in GB from the end of the war until about 1970.? (Just seen an article about Standard Vanguard.)

[alabbasi]

For the most part yes. Thicker Russian steel that rusted at an alarming rate.

[2xChevrons]

Lester H said:

This will have been asked before and it’s a bit of a ‘pub bore’ topic, but was thicker steel used in everyday family cars on sale in GB from the end of the war until about 1970.? (Just seen an article about Standard Vanguard.)

It's hard to generalise - as ever, using thicker steel sections cost more money which manufacturers wanted to avoid if they could help it.

A lot of early unitary-build cars had relatively thick body steel when compared to the panels of body-on-frame cars and tended to be somewhat 'overbuilt' because engineers were still somewhat feeling their way with the the new methods and erring on the side of caution. But not always - the Morris Minor used quite thin steel (20-gauge/1mm) for a lot of its exterior panels because their strength was in their domed/curved shape not the metal itself (this is why 'jelly mould' shapes were so common in the 40s and 50s - the alternative was to use corrugated flat panels as on the Citroen 2CV and H-van) but 18-gauge (1.2mm) and 16-gauge (1.5mm) steel for the floorpan, bulkhead and front 'chassis' legs.

The Vanguard (body-on-frame) was deliberately overbuilt because it was intended as a 'world car' with an eye on the Empire/Commonwealth markets. So the chassis was made from 14-gauge steel and most of the body was 18-gauge with 16-gauge doublers in areas of high stress. Which is why the Vanguard's were so durable and so ponderous. Standard went the other way with the Eight, which was intended to use as little steel as possible for weight and cost savings - it's a unitary car but lightly-made from 20 and 22g steel, which is reflected in their survival rate!

That became the industry standard for mass-produced unitary road cars, though - a Mk1 Cortina or Escort is nearly all 20g with bits of 18g around the suspension and steering mounts. Designers became cleverer at getting strength from flatter, thinner panels so you see the end of the 'jelly mould' in the 1960s until you get to 70s stuff like the Alfasud which is virtually all 16g for the structure and 20g for the panels. - which is why the only weigh 860kg and partly why they fizz so readily.

I think there was a decline in the inherent quality of the steel, too. Maybe manufacturers came to rely more on paint and rotodip/electro-priming for corrosion resistance, or it was just cost cutting? Speaking of Standards, my Dad has a 1940s Flying Twelve, made at the peak of post-war shortages. The entire inner rear of the body, behind the seats and rear cabin trim and inside the boot, is not only unpainted but unprimered - just bare metal. It's been like that since Attlee was prime minister and other than some tarnishing and some freckles of surface rust it is essentially pristine. I can't believe a 1970s Mini's boot would be the same if it wasn't painted.

Or am I getting things wrong and is it the higher-quality metal that rusts more readily (I'm not a metallurgist!)? Is the fact that my Dad's Standard hasn't turned to ferrous oxide a sign that there isn't much ferrous material in it and all the iron is already bound up with other impurities?

Edited by 2xChevrons on Sunday 29th November 14:33

[LuS1fer]

It's not necessarily the steel, it's the degree of protection it had.

A mate once crashed his dad's 1968 Jag 240 and the wing was torn back. Loads of rust in there and not a drop of paint on any of it.

I think the biggest advance was the plastic wheelarch liners and the zinc plating of steel.

[bartelbe]

The other issue is water traps which led to rust on many older designs, which modern designers seem to be better at engineering out. Water could get trapped between double skinned panels and in box sections. Even worse was if mud got into a box section or stuck next to a panel. The mud simply didn't dry out, creating the perfect conditions for rot.

As for plastic liners, not sure they are that great. Sure they stop the wheels sand blasting the paint off panels next to the wheels but if you look behind them you often a big old pile of rot causing mud and other crap.

[finlo]

bartelbe said:

The other issue is water traps which led to rust on many older designs, which modern designers seem to be better at engineering out. Water could get trapped between double skinned panels and in box sections. Even worse was if mud got into a box section or stuck next to a panel. The mud simply didn't dry out, creating the perfect conditions for rot.

As for plastic liners, not sure they are that great. Sure they stop the wheels sand blasting the paint off panels next to the wheels but if you look behind them you often a big old pile of rot causing mud and other crap.

A plastic liner is preferable to Ford's soggy carpet type stuff.

[grumpy52]

A combination of quality of metal used , the design of the body and how many water mud traps there were , very little if any rust proofing and the type of winter treatment used on the roads .
Some paint colours also aided the preservation of the metal .
Some garages also cottoned on that spraying old engine oil to the undersides of customers cars helped keep the rust at bay . My fathers Hillman super minx certainly benefited from oil and Tartan Red paint as it was not welded until it was over 10 years old .

[silverfoxcc]

I recall Vauxhalls in the late 50s esp the first Victors visibly rotting. My mate,even at 11, was really into insects and reckons they had finer lacewings than the actual insect.

[Mr Tidy]

I had to laugh when I saw the reference to a Standard 8!

I'm sure my mate's younger brother had one of those back in the early 80s and it had no boot-lid - the only access to the boot was by folding the rear seat-back down.

As I was born in 1959 I don't have much experience of 50s and 60s cars, but I do remember my Dad's 1954 Austin A40 wasn't as rusty when he sold it in 1967 as his 1964 Hillman Minx was when he sold that in 1972!

[a8hex]

grumpy52 said:

Some garages also cottoned on that spraying old engine oil to the undersides of customers cars helped keep the rust at bay .

As did some manufactures it seems. Jaguar appear to have carefully designed a rear oil seal on the engine so that it carefully sprayed the underside of the car as you drove.

[alfaspecial]

One of the benefits of positive earthed vehicles was built in rust prevention.
Negative earthed vehicles are far more prone to rust - when the change was made (1950's) car manufacturers did not properly engineer a solution to the problem.

[austin]

As I am (slowly) replacing a huge amount of rust / metal on a Morris Minor at the moment I can back up the lack of rust protection point made above.

At best I reckon it was driven past the paint factory on a windy day, a lot of bare metal still visible once you start cutting away the chod.

That's then compounded by failing waxoil or similar that's gone hard and come away from the metal and created a perfect moisture trap, rusts away in there without anyone being able to see it. I'm removing it all and doing a proper paint job on it.

[crofty1984]

alfaspecial said:

One of the benefits of positive earthed vehicles was built in rust prevention.
Negative earthed vehicles are far more prone to rust - when the change was made (1950's) car manufacturers did not properly engineer a solution to the problem.

Why is that? I'd genuinely like to know.

[LuS1fer]

alfaspecial said:

One of the benefits of positive earthed vehicles was built in rust prevention.
Negative earthed vehicles are far more prone to rust - when the change was made (1950's) car manufacturers did not properly engineer a solution to the problem.

Shame nobody told BMC because my positive earth A40 Farina was just as rusty as any other car.

[alfaspecial]

crofty1984 said:

alfaspecial said:

One of the benefits of positive earthed vehicles was built in rust prevention.
Negative earthed vehicles are far more prone to rust - when the change was made (1950's) car manufacturers did not properly engineer a solution to the problem.

Why is that? I'd genuinely like to know.

Hazy memory from physics, forty years ago.... positive electrodes rust faster than negative electrodes.
This may be of interest: https://www.motorsportmagazine.com/archive/article...
Quote "Whether car manufacturers were aware that body corrosion would occur with positive to earth installations we do not know, but in our opinion it was a genuine effort on their part to improve the efficiency of the electrical system."

I think the physics also links to the principles of electrolytic rust removal


But I may be wrong!

[2xChevrons]

silverfoxcc said:

I recall Vauxhalls in the late 50s esp the first Victors visibly rotting. My mate,even at 11, was really into insects and reckons they had finer lacewings than the actual insect.

The original F-type Victor (the one that looks like a miniaturised '57 Chevy) was infamous even in its own time for rapant and rapid rust and lumbered Vauxhall with a reputation that it took decades to shift. The Victor was designed for high volumes and low price - in contrast to Vauxhall's previous decidedly middle-class market position - and also 'benefited' from GM's lead and experience in making unitary body shells (in fact Vauxhall had been one of the leading divisions in this area within GM itself) which meant that it could use the miniumum amount of steel possible and a relatively low unladen weight for its size. It was also the first Vauxhall (and first GM product) to use a stressed floorpan, where the entire floorpan and bulkhead takes the whole load of the car, unlike the older unitary Vauxhalls (and stuff like the Morris Minor and Ford Consul) which are 'unitary' but have box- or U-section channels welded to the floorpan to do most of the work.

The flamboyant styling was the main issue, though. The wraparound front and rear screens (including the 'dog-leg' A-pillar shape) led to door apetures with a shape that was beyond the abilities of the standard door seal material of the time, and which in the best case scenario required very careful fitting and adjustment to keep the water out. The exhaust tailpipe was 'hidden' inside the jet-like rear overrider which just caused the lower rear wing on that side and the rear valance to fill with corrosive exhaust gas and water vapour. On top of this were the usual indifference of the time to eliminating seams, voids and pockets where the various elements of the floorpan, sills and bulkheads were welded together.

The Victor was built in quantities and at rates that Luton was not used to and even by the standards of the time the body protection used wasn't great - the completed body shells were simply cleaned with thinners, dried and then dipped into a bath of primer. This did not cover the car above the waistline (since the shells were suspended on the overhead track by dollies and slings passing under the roof through the door apertures). I remember speaking to a Cresta Club member who had restored a number of P-type Crestas and Veloxes who said that when you stripped the paint off you often found a 'tide line' of primer that sometimes barely came halfway up the doors, implying that Luton was not very diligent about keeping the primer bath topped up to the correct level. I doubt the Victor was any better.

For the North American market GM head office warned Vauxhall about the fierce amount of salt (and other corrosive de-icing mediums) used many cold parts of the USA, and Vauxhall's response was to use a hot-spray plastic undercoating on NA-market cars. This didn't work since it easily chipped or cracked and was actually itself corroded by some of the stuff sprayed onto roads in some states, which just let water get behind the undercoating and collect against the floorpan, bulkhead and wheel arches. Combined with the leaky door seales, Victors tended to rust from the inside out (rather than the usual way of first going at the wheel arches and lamp bowls, then the outer sills, then the foot wells and then around the windscreen seals etc.). In severe cases the stressed floorpan would suddenly fail and the car would basically split in two. UK-market cars didn't even have the benefit of the undercoating, hence why original Victors often only lasted five years or so before going to the scrapyard with huge holes in their bodywork and underside.

If I remember right it was the same Cresta-restoring chap who said that he once did some body work on a friend's Silver Shadow and the thickness of just the paint on the Rolls-Royce was greater than the metal and paint combined on an ordinary car of the same period. True or not, it doesn't seem to stop Shadows rusting at quite a speed once the moisture gets in.

alfaspecial said:

One of the benefits of positive earthed vehicles was built in rust prevention.
Negative earthed vehicles are far more prone to rust - when the change was made (1950's) car manufacturers did not properly engineer a solution to the problem.

My understanding was that it was the opposite, and this is one of the reasons why negative earth became the standard. The positive/anode side of an electrolytic circuit will always be the sacrificial side and thus the one that rusts. On a positive earth car this means the bodywork, especially around any areas that collect damp (wing seams, door bottoms, overlapping body sections) and where any electrical fittings mount to the bodywork (lamp units). On negative earth systems the electrolytic corrosion (not including any other factors such as rust traps, poor paint, badly-prepared metal and so on) will tend to happen in the (positive) wiring - especially the body connectors - rather than the (negative) body, and it's easier to protect wiring and connectors from corrosion and cheaper to replace them if they do corrode. Apparently this is one of the reasons why Lucas electric had such a bad reputation in the 70s because the British industry switched from positive to negative earth and Lucas didn't alter the material or design of their wiring or connectors to suit, so they were especially prone to corrosion and bad connections.

austin said:

As I am (slowly) replacing a huge amount of rust / metal on a Morris Minor at the moment I can back up the lack of rust protection point made above.

At best I reckon it was driven past the paint factory on a windy day, a lot of bare metal still visible once you start cutting away the chod.

That's then compounded by failing waxoil or similar that's gone hard and come away from the metal and created a perfect moisture trap, rusts away in there without anyone being able to see it. I'm removing it all and doing a proper paint job on it.

Minors are especially nasty. I sometimes think that Issigonis was not merely indifferent to rust prevention but actively wanted to encourage it. Maybe he held shares in Dinitrol or something? The Minor has loads of nasty overlapping elements in its floor pan which are a breeding ground for tinworm. I believe that for much of the Minor's production run Cowley used a similar rather crude primer bath setup as already mentioned at Luton, while Austin was one of the first UK car makers to install rotodip cleaning/priming baths at Longbridge when the plant was rebuilt in the early 50s.

Edited by 2xChevrons on Monday 30th November 17:11

[NMNeil]

I worked at a garage in the early 70's and a customer had asked for an aerial to be fitted to his DAF.
The mechanic who did it marked and taped the spot and intended to drill a 1/8" pilot hole. The drill pushed through the wing before he even turned the drill on, the metal was that thin.

[droopsnoot]

For all of the usual criticism of seventies Vauxhalls rusting while you wait, I blame some of it on Vauxhall applying underseal and making a big thing of it. My Dad bought a Morris 1300 new in 1970, and late summer was always the time that he'd get under it and make sure the underseal he'd added was OK, touch up what needed it. I wonder whether Viva (and other 70s Vauxhall) owners thought that wasn't necessary because of the emphasis placed on the factory protection. This is part of the brochure.

[Glosphil]

My father's 1964 Vauxhall VX-4/90 had door sills that had rusted through by 1968/9.

[Hippea]

Which cars of that era were best for repelling rust? I’ve heard Volvo Amazon’s were good, is that down to a mixture of thick steel and less water traps?