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MG MGB Technical - interior panel rust

When I took the interior vinyl panels off my 1970 MGB (behind the seats) I noticed the beginnings of rust. Meanwhile there is no sign of rusting on the exterior rear fender side. My question is how to take care of this… access is very tight, cannot reach down into the bottom areas to sand, prime, re-paint. Someone suggested spraying insolating foam which will expand into the area. Have thought about spraying or pouring a rust remover into the area? But how do I know any of this will stop the rusting process and create a bigger mess later on… especially the expanding foam idea?
Danny Jacob

Two panels meet at areas round there Denny so even if you could get to it you'd never get in the joint where you need to be. Personally, I would Clear Waxoyl it, after some warm days when the panels and seams are dry. This liquid soaks through by capilliary action and will appear at any open joints after a week or 2. When the solvent evaporates it leaves a soft wax behind. Another nice thing is you can easily wipe it off with white spirit if there is any painting to be done later and it can also be redone every so often as the new fluid softens and mixes with the old. Rich.
Rich

Is this in the cavity between the panels? If so it is very common because it is impossible to paint *after* a new dog-leg, for example, repair panel has been fitted and the act of welding always burns off some paint if the panel is treated before hand. Waxoyl is very good and I use it extensively but I have found that unless the ambient temperature and panels are hot enough to keep it liquid while it *does* flow (difficult in the UK) it just bridges the top of the very narrow gap between the sill and the cover panel and leaves the space below and between them untreated. In lesser temperatures it can be a translucent liquid in the tin but the act of spraying causes it to become a gel which sticks to the panel rather than runs. This is why repair panels in this area often rust out quicker than the originals, which were dip-primed. I've had to replace all four of mine on two cars. Now I inject plenty of clean engine oil into those cavities with an oil gun, making sure I spray it as far forward as I can as well as downwards. The oil does run under pretty-well any conditions, only dripping out of the join between the cover panel and the sill and castle section at the bottom, allowing the cavity to fill up and get fully coated. It does then drip for several days afterwards, or more or less depending on the size of the gaps at the bottom.
Paul Hunt

Yes it looks like you've got similar temps to us at the moment. I wish it would warm up, next week they say. I do a bit of waxoyling as and when I've got a wheel off, trim out, etc. At this time of year there's no problem if you warm the panel first with an ordinary hair dryer. It's surprising how much heat these kick out now. Then spray, and warm again, and the stuff runs like water, do a panel in a minute. Good for small paint repairs too, stops blooming. Just remember to wipe the grease off before you put it back on her dresser :-)
Rich

Foam will just trap moisture and make the problem worse. Go to Lowe's or some place like that and get some Penetrol and a cheap garden sprayer. Use the sprayer coat the inside of the cavity with the Penetrol. (Penetrol is a paint additive that also happens to be a good rust preventative. Unlike Waxoyl, it will flow well under most temperature conditions.)

HTH!
Rob Edwards

Yep, I agree with not using foam. Once it does rust out any foam in there is a hazard when welding. It gives off toxic fumes when it burns.
Simon Jansen

thanks for the good advice abt the foam idea. makes sense. PO spayed a lot of undercoating type stuff in trunk, etc... a real mess to clean out. I like the idea of seeing problems develop before they become disasters. Tearing down my car for respray, wonder where other potential rust problems are lurking?
Danny Jacob

Danny, I like penetrol for this application. It is a paint flow agent and can be found in the paint department at Lowes and Home Depot -- rust treatment use is printed on the can. It will runout for a couple of days after you apply: I think it is easier to apply than waxoyl and perhaps better in some applications.
Regards,
Dennis
D F Sexton

Danny, if you want to try rust removal instead of just slowing the rust, try Oxisolve from the eastwood company. They have a website where you can buy it online. Just saturate a rag with the solvent and tuck it in the fender. It actually dissolves the rust and creates a zinc coating that resists future rust. If you keep the area wet with it for a couple days, 99% of the rust will be gone, then you can paint or Waxoyl or whatever you prefer. It really works!!!
Jeff Schlemmer

This thread was discussed on 02/03/2005

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