VCCA Home Forums TECHNICAL - GENERAL Body - Sheet Metal, Paint & Wood "Oil Canned" Rear Fender

While removing the rear fender side stainless from my 55 Belair during restoration a small area of the panel above the wheel house "oil canned" in. It can easily be pushed out from the inside and shows no signs of any damage, this car is rust free and never been hit. Seeing the molding held it place all these years I guess I can reinforce the back until it's painted then when the molding is reinstalled it should hold. Is this a common problem in these long fenders and is there a way of fixing this problem? Also does anyone know a paint code or seen a fizz can to finish the inside of these side moldings, it looks to be an off white? Thanks for the help

I know there is a way to "shrink" metal, but I don't know how to do it or if that will solve your problem. This did work on my '55 hood, but I didn't do the work myself.

You might want to check some body work books.

Vanst: You didn't "dent" (i.e. cause damage to) the fender when you removed the trim, at least I don't believe that's what you meant. Didn't you mean that, without the support of the trim, the fender naturally will 'oilcan', but returns to normal shape just gently by pushing it out? Maybe I misinterpreted your original post. :confused:

-Bob

vanst,

Your question on body panel "oil Canning" (panel buckling) is a "loaded" question. Chevrolet struggled with his phenomenon over the years and it seemed to have multiple reasons as to why it occurs. In some cases it was a result of the design, in others (still design dependent) it was caused by build variations and part quality, and it can occur due to changes in the vehicle structure over time. Two identical vehicles might have totally different sensitivity to the condition. The older body/frame type vehicles are more prone to expose the problem that are the newer Unibody vehicles. Be thankfull that your condition is not currently a permanent one.

Quarter panels were not the only areas that experienced problems. Front fenders were known to "buckle" under certain conditions. The 1971 thru 1976 Impala - Caprice vehicles used a "mastic" patch on the inner surface of the quarter panels and in some cases on the inner surface of the front fenders as a "Band-Aid" for this condition.

Chevrolet conducted vehicle evaluations for Jacking, Hoisting, an Wrecker Towing at curb and full rated load searching for such things as panel buckling on every new model that they introduced. Who in their right mind would use the service jack and jack up each corner of the vehicle while it is at a full passenger load? The dynamics involved with the use of a wrecker can cause panels to buckle as well. Even having done those evaluations didn't mean that you were trouble free because of the variability within identical vehicles. Convertibles, Hardtops, and Station Wagons were more susceptible than were Pillar Sedans for panel buckling

Back to your problem. You said that your vehicle is rust free. Even so, you should take a good look at the body mount cushions and the body cross sills that they attach too for any signs of deterioration/corrosion. It's kind of like having a bad foundation in your house, not knowing it, seeing a crack in a wall, and wondering what caused this?

Bowtie Bob, I guess I mean to say the car looked great with no signs of the "oil canning" until I removed the side molding.

Now I have this problem at the front edge of the right rear wheel house. Any ideas? Thanks Terry

It sounds like the condition is a temporary one, just until you re-install the trim that reinforces the sheet metal and prevents the 'oilcanning'. The problem then is how to prevent the sheetmetal from flexing while you're working on the car, painting, etc. - is that correct? If so, how about a reinforcement piece on the back side of the sheetmetal, which could be taken off after the body is re-installed, just before the trim is put back in place? Maybe I'm not visualising the problem correctly and, if so, I'd be glad to stop over and take a look and give you my 2¢ worth. Let me know.

-Bob

Bowtie Bob,I work on the car basicly every night and weekends. If you have time and wish to stop over and give me a second opinion that would be great. I'll send over my number on a e-mail or I'm in the book. Thanks Terry

"...used a "mastic" patch on the inner surface of the quarter panels and in some cases on the inner surface of the front fenders as a "Band-Aid" for this condition."

oldie, if you have the time, could you expand on this comment? In addition to 'helping' the 'oilcanning' it would sound proof a little. If it can't be seen, why not? is there any downside to using this patch?

Well Gator, The "Mastic Patch" I referred too was used (in my opinion) to cover up a short coming in the design of that particular vehicle. When that vehicle was raised using the service jack or hoisted with a chainfall or wrecker sling during its development stage, a buckle would occur in the sail area of the rear quarter panel(s), depending upon which area was raised. I don't know for sure but I suspect there was some body deflection that occured which caused the buckel. Rather than attempt to identify and correct the problem, Chevrolet chose to reinforce the affected area using a "Mastic Patch". As I recall this patch was a fiberglass type material (approx. 1/8 X 6 X 12 inches) which incorporated some sort of bonding and hardening agent. The patch was installed to the inner panel just prior to the vehicle entering the paint oven where it would set-up to be pretty hard. I talked with my old boss this morning, who was the development leader at that time, about the "mastic Patch" and he just laughted.

I don't know about using a patch as a sound proofing material but I don't think it would be practical.

You asked about a down side. I don't recall any down side for Chevrolet's usage other that the expense of using it rather that identifing and fixing the true problem. In their case, if it hadn't worked, they would have just thrown the idea away and tried something else. In vanst's case there is a risk. He could bond on some type of fiberglass patch or even spread a Bondo type material over the subject area which might fix the problem, chase the condition to some other area, or accomplish absolutely nothing other than making a mess. Either his vehicle has had the condition since day one or something has changed over the years that allowes it to occur. In essence, his removal of the stainless trim was the removal of his "mastic patch". If his condition is one that has slowly occured over the years, then reinstalling the stainless may cure the condition for the short term, but at some point in time the condition could become worse. If vanst isn't able to identify the root cause of the problem at this time, my advise would be to reinstall the stainless and hope for the best.

Thanks guys for takings the time to write about the problem. I have planned most of the dat Saturday to investigate the cuase of this problem. I may even use a floor jack under areas of the frame up see if a gentle lift may alter the problem. Being a convetible with the X-member frame and stiffner plates I would if lifting it will show anything, I'll probly need to lift the body itself. I don't feel any rubber seal around the wheeelhouse as was mentioned before and I don't see it for sale in any catalogs I have. If this is the problem it looks as if it would difficult to install. Again thanks for the help and wish us luck! Terry

vanst aka Terry,

Just to clarify something. You mentioned something about a rubber seal around the wheelhouse. What was referred to earilier was body mount cushions and the structure on either side of them. I don't remember what was used in 1955 as a cushion between the body and the frame at the body to frame attachments. In later years it was a large rubber piece that resembles a hockey puck in size and shape. In '55 it may have been just a rubber insulator resembling a section of tire carcass, I don't know. Anyway, you need to inspect the areas where the body attaches to the frame for any deterioration of the rubber insulators or any corrosion to the body cross sills at those attachments.

I don't have any '55 information but I do have some '56 information and in that information it states that the Convertible body to frame has 20 attachments total. Seems like a lot to me but who can remember what was done back then? As good as your car may be, those are the areas where the highest concertration of load is and the cross sills are shaped in a way that allows them to collect debris and corrode from the inside out.

Having judged in VCCA judging over the years, I can tell you that there are a lot of nice looking cars around where the body cross sills are in bad shape.