Hi!

I've been asked whether the rust protection that the Born factory gave the Volvo 300 range changed significantly over the years.

The "early cars" from 76-77 have a worse reputation for quality, but that may have been more due to lower quality steel and plastics than anything else. Design changes, such as the lack of a "nose cone" on Mk2 cars, or the larger bumpers on Mk3s may have reduced rusting on the front end of the car due to stone chips etc, but that doesn't say much about the actual quality of rust protection or painting techniques.

Did very early cars (76-77) have PVC on sills, wings, and valances for example? Did all model years get cavity sealing? Any other significant changes over the manufacturing period?

Cheers

Tom

I don't know much about factory changes but I have experienced the rustiness of most years from 1980, aswell as comparing newer cars of various makes.

I don't think the type of metal or underseal makes that much difference. From my perspective it seems much more like a quality of joint issue as well as quality of application of materials.

Joints that are not flush bluge out inbetween spot welds and these leave gaps that attract water. Newer cars the design are different and don't involve simple spot welded outer L joint. Hard to put my finger on it but they seem to use inner L joints to make boxes.

Additonally its not uncommon for internal sections to be missed entirely because of the wrong technique. An example is the front windscreen corners.

I think my 1980 345 was blistered and rusted at about 4 or 5 years old all over(that sounds very young, but was alot less than 10 years), later cars where much better and generally fail for the above reasons.

A you might know I had a 77 car.

From what I remember there was no underseal on the sills or lower wings as on the later cars. No underseal on the front nose cone type valance (which received many stone chips between 1977 and 1995 when I filled a few holes and resprayed it. From what I remember, the valance wasn't that bad just a couple of small holes. The nose cones where bad though, I think the later ones may have been better painted better inside but that's guesswork (I do still have the original one, what's left of it!). The panel behind the back bumper was not undersealed. The protection was on wheel arches and underside only, beyond all visible seams on wings, sill etc. (not including forward chassis rails). I don't think there was any protection in the way of cavity sealing (I assume that means inside box sections).

Improvements were made by leaving the bottom of the wings open forward of the front wheels (to let air circulate) and undersealing part way up the front and rear wings, valance and sills.

The lower wings rear of the rear wheels rotted out badly in my car, as did all wing to wheel arch spot welds, far worse than later models. Front suspension mounting areas also rotted badly as did front outriggers/floor section. Rear number plate panel upper was bad (still a problem on some later cars).

By the late 1980's (at 10 years old) it was very rotten but I brought it back from near death by having new sills welded on in 1992 for a serious MOT failure. (This was just after I was given the car while at college). In 1995 I had to have the front strut areas welded and also filled/fibre glassed all the wheel arches.

It was very notable in the early 1990's that there were loads of early Mk2 cars (and some late Mk1s) around with far less rust if any visible....very annoying!

Thank you both for that info. The only "official" info I found on the improvements were in the 1978 model year brochure where they specifically mention the pvc lining of the sills - which could mean they didn't do that in the years before.

But I guess the main improvements were "evolutionary" rather than "revolutionary" and the marketing people didn't make a big song and dance about it all ...

Tom

Did they get penny-pinching later on? Late cars seem to rust like nobodies business at the corners of the scuttle panel.

macplaxton wrote:Did they get penny-pinching later on? Late cars seem to rust like nobodies business at the corners of the scuttle panel.

Yep, I think they did - H and J plate cars in the UK seem to suffer more for rust than even slightly earlier examples.

Penny pinching or just couldn't be bothered? You could see where they didn't spray on my June '91 car

trabitom99 wrote:The "early cars" from 76-77 have a worse reputation for quality, but that may have been more due to lower quality steel and plastics than anything else. Design changes, such as the lack of a "nose cone" on Mk2 cars, or the larger bumpers on Mk3s may have reduced rusting on the front end of the car due to stone chips etc, but that doesn't say much about the actual quality of rust protection or painting techniques.

Did very early cars (76-77) have PVC on sills, wings, and valances for example? Did all model years get cavity sealing? Any other significant changes over the manufacturing period?

Sorry for the late answer, but while working on an article 'bout the early 300, I came across the answer.
Early in MY'77 the PVC underseal was introduced as one of the improvements originating from "Operatie Pijplijn" (operation pipeline).

Cavity sealing was market dependant and usually done by the local workshop. Refering to the pic of the '91 innerwing; this area will never have been waxoiled by the factor as the car would have been painted (wing in place) by the time rustproofing would have been applied. On my own car I have seen the proof that our local workshop waxoiled the innerwing cavity.

Main problem cause of the rustiness of the early (pre -79) cars was the use of French steel that contained a lot of impurities. No amount of waxoiling would have prevented that steel rusting (it even starts to rust in my dry and heated attic!).

1986 340. Rustproofing must have been carried out by a chap on a bicycle,and possibly a racing bike at that!
When my car was under two years old I checked all box sections with a light probe through the rustproofing access holes and only got lucky on five occasions! Yes FIVE out of some 50 + rustproofing holes ,and even then you had to look very carefully for evidence that the chap had actually pressed the gun lever before passing by.

Looks like the robot did the easy access underbody, but needed a human for the cavities. Inconsistent comes to mind, but this is a typical factory problem. Probably not enough quality control on the training and technique.

Hi,

I bought my '80 343 2 years ago. B14.1 with Variomatic . About 40.000 miles.
Was prepared to weld the whole thing together. But - it needed no welding at all!

All cavities I found where sealed and in perfect condition. Even on the underbody no rust found.
I'm now wasting my time in technique issues and a little paint repair on the edges of the wheel arches - and that's it.

So it seems to differ from car to car or maybe the RHD's differ from the LHD's ?

Regards
Ralf

Thanks for that info everyone. Seems like the early cars really did deserve their reputation! Still, makes them sought-after rarities now.

Cheers

Tom

I have been breaking an F plate 360 GLE limited edition 5 door and the rust protection really was a half arsed job on it and I noticed the little patch that goes in between the valence and the fog light on the side wasn't even fitted on this one.