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MG MGB Technical - A Question About Rust Repair

Hello, I'm new to the MGB threads, but a long time participant on the midget forums. I'm looking to buy a B of some sort to restore. I found a roadster shell not to far from me that has had new floorboards and sills welded in. I'm thinking of going to look at it, but I wonder what I should look at to see if they were proper repairs or a bodge job. I saw picts of the floorboards and they were spot welded in and looked neat. And I thought that the doglegs would go before the sills? How can I inspect all of this to make sure I'm buying a sound car and not someone else's problems.
Terry Mills

Are the front wings off, if so you can see most of the inner and outer sills, the centre one which is essentially flat and is sometimes called the diaprhragm is harder to check but you can see some of it through the drainage holes. There is also the castle section which sholud be 100% visible . Be sure to check that the jack reinforcing bracket is present and correct. Harder to check is that the car was correctly supported and there is no sag or hog to stop the doors fitting.
this may help.

Stan Best

re the B+G site, click on MGb then go to repair panels
Stan Best

Terry, there are other MG enthusiasts in Oklahoma, do you have any contacts in the area of the car? You might consider joining the NAMGBR, they publish a handy list of members who have volunteered to be listed to aid any other members who might be in the area and would probalby be glad to either inspect the car for you or meet you there. If it's in the KC area maybe I can help also.
Bill Young

Bill's advice is most excellent. Finding an experienced MGB guy to go with you would be really helpful, and the NAMGBR directory is really useful. On trips, it has been a big help on the rare occasions when I needed it. Glancing at mine, I see 17 members registered in Oklahoma: in Broken Arrow, Choctaw, Claremore, Edmond, Guthrie, Midwest City, Newalla, Oklahoma City, Piedmont, Ponca City, and Tulsa.

Other things to look for:

1. Door gaps - are they even? If the car was welded with a sag in it, they won't be.

2. There should be an open vertical seam from the rear of the door opening down to the bottom of the shell, and the front door gap runs down through the sill also. Actually, not "through" the sill, but the front wing join is open; hence a gap all the way to the bottom. The sill runs the full length from the front wheel well to the rear wheel well, underneath the front and rear wings. From that open seam, it runs under the dog leg. That's why it has to go on before the dog leg. The front wing bolts over it. BTW, the sills are a structural as well as cosmetic element in the MGB.

3. look under the car; the castle sections Bill mentions appear as a ribbed piece running from the bulkhead to the rear inner wing. It often rusts in the area forward of the door. While you're under the car, you can see if the old floors have been neatly cut out or not. The floors should show the original stamping pattern. It's possible to do a good job with all home-made panels, but unless the car is VERY cheap, I'd tend to keep looking.

4. Unfortunately, sill repair panels are available that just cover the area under the door that you can see. Make sure the full length ones have been used.

5. If you bend about a one-inch "L" in the end of a piece of coathanger wire or similar, slip the "L" end in a few drain holes and see if you can rotate the wire with the "L" (now upside-down) inside. If you can rotate it toward the center of the car, the diaphragm is gone. Usually the bottom of the diaphragm is the first thing to go - long before there are any visible signs of rust on the outside.

6. If the engine is in the car, I always ask the seller to demonstrate use of the jack sockets and watch for any give in the sill. If he refuses, or if there is, you've got trouble. If the engine is out of this car, then this test is less effective.

Check out all the drawings in the Moss catalog to see how all these parts fit together. If you already done some welding on a Midget, you already know that while very tedious and time-consuming, these repairs are not particularly difficult. Beware the freshly painted or primed shell - you want to see exactly what's going on.

Allen Bachelder

now im at work and cant think of the correct name, but there are two line that start from above the trunk and then down below the trunk lid. Sometimes when a car is redone they bondo over it, I dont know if the car has paint on it or not but its another way to check for prior work done, although not structural work. Hope someone ca explain it better than myself. Im pretty sure its in the DIY MGB Resto book

Allen B. Quote > "6. If the engine is in the car, I always ask the seller to demonstrate use of the jack sockets and watch for any give in the sill. If he refuses, or if there is, you've got trouble. If the engine is out of this car, then this test is less effective."

Sorry, but I wouldn't let any one near my MGBs with the original jacking equipment. Well I would if Neal Armstrong was still on the moon at the time! The late 60's that is.
The jacking points were known to MG as being a flawed design. I read [can't find the official text] that the points were not suitable for use & so have these owners from the archive>

"I have seen an official recommendation, as I recall, that the factory jacking points should not be used on a car more than three [[[THREE!]]] years old (or more than three years since a comprehensive sill/castle rail/crossmember replacement, one assumes) unless they are *known* to be structurally sound."
"I have read that the original MG jack should definitely not be used on older MGBs and MGCs as it stresses the body terribly. I think I also read that MG recommended that the original jack not be used on cars more than four years old."
Paul Morgan

I looks like from the photos that the jacking points were not reinstalled. Maybe a good thing? It also looks like that the doglegs were cut off and rewelded on. I assume this means that complete repair sills were used and not the shorts patches mentioned above? The front fenders are off and the sills run all the way forward. It worries me though that the seller states that the sills were already removed when he got it but he supported the car properly in the middle to weld the new ones in. This may be a great shell, but I don't know. I'm thinking about passing. I would have to drive 120 miles or so to look at it. Its in the Oklahoma City area.
Terry Mills

Thanks for all the info confirming that my suggested jack-socket tests are a good idea! If a recently-repaired sill section cannot withstand stresses that should be expected of a car less than three years old, that car has NOT been properly repaired. I stand by my original statement - all the more so for having read your comments! Thanks for your confirmation!

Now, if anybody wants to jack my '73 B/GT or my '65 B up by the jacking points, I will expect it if the car is for sale and the "jacker" is a potential buyer. I've done it, just to demonstrate to myself that I did the job right. I would never use the factory jack for any other reason (like, for example, changing a flat tire on the road), but I would never, NEVER, buy a car that could not pass this test. If you don't want me to try this on your car, I simply won't buy your car. That's OK. There are others.

The quotations you selected make it clear that this is OK on a car less than three (or even four) years old. If a restored car cannot meet that criterion, it is not restored!

Your cue is in the gaps around the doors. If the car is sagging, the doors cannot be made to align correctly. Maybe a little bondo around the door edges could cover the problem, but a little whittling with a pocket knife when the owner isn't looking would quickly show that. If in doubt, keep looking. There are still lots of good MGBs out there that ARE what they appear to be. My wife and I have a mutual agreement about buying anything for the house: it has to jump out and say "buy me!". The same for a car, if it doesn't jump out and say "buy me!", keep looking for the one that does.
Allen Bachelder

If someone took a pocket knife to a car I was trying to sell, they had better be prepared to defend themselves. You don't know this owner from Adam. Lets say that it may have bondo on the hood to repair damage. I don't recommend that you whittle away at the hood just to find out. A safer method may be to use a small magnet with a piece of paper to protect the paint.

Mine is a 74 and I use the point where the "jack socket" is welded on to place my floor jack when lifting. It probably puts less stress on the car than the original jack but that is just a guess since I don't have the original jack to test it.

I stand corrected on my pocket knife suggestion! Yes, certainly, a magnet would be better! I too would ask buyers to check their pocket knives at the door. But then, don't we get a bit nervous when guys come around with the oft-recommended ice picks?

I need to clarify that I did not say I would come "near [your] MGBs with the original jacking equipment." What I did say is that I'd ask YOU - the seller - to jack the car on the original jack. I didn't think of it in my last response, but there is a difference. I went on to say that if the seller refused to do so, "you've got trouble". Perhaps I should have refined my statement to say "you may have trouble".

If I made any statement to imply that a buyer has a right to potentially damage a car that's for sale, I spoke carelessly and apologize.

If a seller tells me the car has brand new sills, castles, diaphragms, jack socket supports, etc, he should have no problem doing the "jack test". Otherwise I would not buy the car unless there was a pretty compelling reason to the contrary. For example, if the price was very low, I might buy it knowing I'll need to replace the sills.


Allen Bachelder

When I restored my '67 Roadster several years ago, I did'nt even bother to install the jacking point hardware. This seemed, to me, to be asking for trouble from a weak design. Ray

Part of the problem with the original jacking point on the MGB is that it lifts the weight of half the car with both wheels on one side off the ground. Modern cars tend to have four jacking points wheras the MGB makes do with two.
Another problem is that the original jacks are not a good design, are up to 45 years old and may also be fatigued and fail.
But I agree with Allen the jack test done with care is a reasonable request when purchacing.
Although mine are sound, I never use the original jacking point I always use a trolley jack under the front crossmember or rear spring.
R J Collier

Also, with the jack test, as the jack begins to bear some weight, one ought to keep a close eye on the sill. If it shows any sign of flexing, one can halt the test right there before any cosmetic damage is done. That alone would be sufficient to answer my question.

Allen Bachelder

This thread was discussed between 19/02/2007 and 25/02/2007

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