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MG MGB Technical - inner wing damage

I am in the process of checking under my newly acquired mgbgt and discovered this morning a very small jagged hole in the inner wheel arch at the centre of the wheel arch just above where the inner and outer wings meet. There is no sign of rust and no bubbling of the outer wing. I thought I might inject waxoyl under pressure either throught the hole or by drilling a small hole in the b post. I would appreciate any advice on whether this is a good idea and on how to seal the hole without welding.

Rod
R E Merrall

From your description, it sounds like a drain hole.

I found a small plate spot-welded into both wheelarches and was informed by several people that there is a drain hole behind it.

Dave O'Neill 2

A jagged hole isn't likely to be a purpose made drain hole. I fitted new outer and inner rear arches on my GT and don't remember any drain holes - there shouldn't be any rain in that area, so why have a drain?

I assume we are talking about the rear wheel arch here as you mention drilling through the B-post. Don't do that. Take off the trim panel inside the car behind the door opening and you will gain access to the area above the wheel arch and will be able to see the top of the inner arch. If no repairs are needed, spray the area with wax while the weather is warm and it will creep. It helps to dilute the wax slightly with white spirit.

The danger point for rust, as always, is where the two panels meet, in this case the outer wing and the inner arch meeting at the wheel arch lip. Rust starts at the lip and works upwards from there.

Can you get a photo of the hole and post it here?
Mike Howlett

Thanks for that Mike its very helpful. It is not a drain hole. I will take a picture and post it asap.
R E Merrall

Picture of hole attached. What's the best way to seal it?
R E Merrall

Have to admit I don't know how to load picture. When i select file it tries to load then says no web site. Help!
R E Merrall

Rod, this is how you load a picture.
1. click on upload at the bottom of the comment box
2. click browse and pick the photo you want to upload from your PC, Camera, or Phone
3. click submit in the upload box - you will get confirmation that the upload has been successful.
4 Finally click submit at the bottom of the comments box

Andy

Andy Robinson

Thanks for your help. Picture of hole attached and would really appreciate advice on how best to close it without welding.

R E Merrall

That doesn't look like corrosion to me. I know from bitter experience how hard it is to get things right when you replace the outer rear wing and/or the inner wheel arch. As originally made the inner arch would come right down to the lip of the outer wing, so either or both components must have been replaced in the past. I guess whoever did it had as difficult a time as I had and what you see is the way he had to cut the inner arch about to get it all to fit. I had to cut mine too, but I did manage to get it down to the lip.

You are quite right in wanting to fill that gap so that water doesn't get sprayed up between the panels. You could use a number of things; seam sealer would probably be my choice with a light coat of underseal on top. there are many types - just search for them, but to give you an idea here is one http://www.frost.co.uk/brushable-seam-sealer.html. It needs to be flexible when dry. A thick wadge of underseal would also seal it. Or you could use RTV silicone mastic like you would use in a bathroom. Anything to keep the water out.

Getting wax down from above is a very good idea once the gap is sealed, then any dampness that might get in there shouldn't attack the panels. Best done in warm weather so it will run down. Access can be gained from behind the trim panel for the front part, and from inside the boot space for the rear part.
Mike Howlett

Thanks for the advice, I will certainly look into seam sealer. I have taken off the interior trim and sure enough the wheel arch is easily accessible. I'll shove plenty wax in there although surprisingly there is no sign of rust.
R E Merrall

That looks remarkably like the plate that I mentioned above, but with a hole in it.

Dave O'Neill 2

I certainly agree there seems to be a plate, but the hole is ragged and as Mike said why would there be a drain hole there. Strange.

I like your car. I wanted a chrome bumper but a 1975 gt was for sale locally and was in great condition. My wife and daughter preferred the rubber bumper so what could I do! I'm under the thumb I know.

Regards

Rod
R E Merrall

Far be it for me to go against what Mike Howlett says…… but in this case I agree with Dave.

There is a drain hole with a cover plate in the centre of the arch just above the lip. Looking at yours I would say it's past it's best and needs fixing if it's not to get a lot worse. Take the underseal off and the plate will be all but non-existent! It needs to be removed and the arch repaired before the tin worm spreads.

Why a drain there I have yet to understand and the only reason I came up with is the possibility of water entering via some of the seams in the top of the wing or at the qtr glass. But why put it at the top of the arch, who knows?

Best of....
MGmike
M McAndrew

"why would there be a drain hole there. Strange."

Indeed, it is at the top of the arch. Any condensation forming near there will simply run down either side of the arch, I can't imagine any running out of a hole up there at all. Unless everything below it is full of water :o)
Paul Hunt

Hmm. One can only go on one's own experience. As you can clearly see in the accompanying photo, taken in 2006 while in the midst of my rebuild, there is no sign of any drain hole on the new Heritage inner wheel arch. As Paul said, I can't understand why there ever would have been one. What good would it do? 'Tis a mystery to me.


Mike Howlett

Whatever the rights and wrongs all agree it needs fixed. What I am thinking of doing is to clean up the area, which I have done, and bond a metal plate over the damaged area. Then a good layer of underseal on the outside and waxoyl on the inside.

While on the subject, all the underseal on the car is in perfect condition. Is there any advantage in putting on another coat?
R E Merrall

I've just looked in the archive for 2014 and found my original thread, entitled "Rear Wings/Arches".

It seems it was MGMike that mentioned the drain hole.

No-one else commented on the spot-welded plates.
Dave O'Neill 2

Mike H, sorry if my post caused offence. It wasn't intended to and was a poor choice of phase on my part.

Your experience fits with mine on "new" arches ie no hole. I think I might have an original NOS Rover arch knocking around the garage which comes with the hole (I'll see if I can get a pic at the weekend for comparison). I've also got a bare shell with the same plate which will be removed before paint!

Best regards
MGmike

Rod,
there's little or no DISadvantage therefore my take on it is add more :-)

Best of...

MGmike
M McAndrew

No offence taken Mike McA. As I say, in my experience (which is limited to a '71 roadster I owned for 12 years, and my current '69 GT) was that a hole and plate were not part of the inner wheel arch panel. It seems that such things do exist, but for the life of me I can't understand why.

Are you going to the Bo'ness Hill Climb this year? I hope to be there with the Lotus Drivers Club in my recently finished Elan Sprint FHC.

Mike H
Mike Howlett

Thanks for all your help guys. Thought you might like to see finished repair. Needs one more coat of underseal.

R E Merrall

Mike H,
I too can't fathom why they are there.
Wasn't planning on going to Boness as I'm working away all week if very limited time to do all those domestic duties expected of me. But I might be tempted if your new toy is present :-) Drop me an email to confirm your attendance and I'll see if a pass out can be arranged....

Rod, Looking good.

Best of....
MGmike
M McAndrew

This thread was discussed between 09/08/2015 and 13/08/2015

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