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Rust hole wisdom

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Thanks Jack ... I read your article, and this one you just posted, with great interest.

This weekend I will take a much closer look at the state of my dogleg, take and post some better pictures. I'm a born optimist, so maybe it will be better than it initially looks :smile:

Haynes MGB Restoration manual has a line I love: "it takes an awful lot of rust to make an MGB unsafe"!
 
Julian,

That is a true statement about taking a lot of rust to make an MGB unsafe. This was MG's first unibody car and they were massively over-designed. I read in one of my MG history books that one sill prototype, placed in a jig that measured torsional rigidity, had about 90% of the torsional strength of an entire MGA frame. That was <u>one</u> sill unit. Now recall that the MGB has two of those, plus the central tunnel that also provides a lot of chassis strength.

Early crash tests of B's were very succesful because in a front-end collision, the front tires crumple straight back into the sills, which feeds the impact under and through the car to the whole unibody. I have seen photos of barrier-crashed B roadsters with massive front end damage but the doors still opened. In this respect, they were on a par with Volvo as far as energy absorption and dissipation and way ahead of their time.
 
Julian - take some photos up underneath at the bottoms of the "castle rails" - front where it curves up & rear by the spring hangers...if the bottom is solid & the interior of the sill (under the carpet) is solid, replacing the outer rocker isn't hard.....
 
Jack_Long said:
I guess mine was the exception, then.
Click to expand...

Jack - with all due respect, I would suggest your B is an anomaly. The dogleg covers the outer sill rear trumpet and there is maybe 1/4in clearance space between the two. Rot starts inside the trumpet/kickup and eats outward and downward.

But don't take my word for it, read Porter, Twist, Robson, et al and see what they have to say.
 
Scott,

I don't have experience with enough MGBs to say with authority, but what appears to have happened with mine is that crud and salt water accumulated in that 1/4 inch space between the outer sill and the dogleg (which is really just a part of the quarter panel)and rusted in both directions - outward toward the outer sheet metal of the dogleg, and inward into the sheetmetal of the outer sill. The amount of rot in both pieces was about the same, suggesting that they had both been rusting for the same amount of time. The rust did not appear to have been coming from <u>inside</u> the trumpet area of the sill, but rather from that "sandwich" area under the dogleg.

It may be that this is because my car was Ziebarted when new - there is a row of yellow plugs with their logo on them that I found when I removed the rubber sill covers to re-carpet the car. It appears that whatever they injected into the inner sills kept them intact. The Chicagoland web site that I referenced in my earlier post made a similar statement - that the car with the intact inner membrane and inner sill had been rustproofed from new.
 
Jack_Long said:
It may be that this is because my car was Ziebarted when new - there is a row of yellow plugs with their logo on them that I found when I removed the rubber sill covers to re-carpet the car. It appears that whatever they injected into the inner sills kept them intact. The Chicagoland web site that I referenced in my earlier post made a similar statement - that the car with the intact inner membrane and inner sill had been rustproofed from new.
Click to expand...

Could be. I've owned a couple of Bs and when the dogleg has a hole in it big enough for a baseball, this is usually what lurks beneath...

sillold.jpg
 
jlaird said:
Wonder how Jay Leno does it? Supose he has an accountant that tracks parts and time on each vehicle.
Click to expand...


Jack Jay be making 15 Million Bucks a year at that rate you can drop a few an not even notice it! Letterman, on the other hand be a car man too but he only make 31 million bucks a year so he be a bit slower!--Keoke- /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif
 
Trash, water, et.al. gets in between the outer fenders & the rockers & causes rust in both directions...that's what is meant by "MG's rust from the inside out"...Ziebart protects the inside of the sills where it is injected but can'ty do anything about the area between the fenders & rockers - that's why, when I put front fenders back on an MGB, I put washers between the rocker & fender - so I can wash the trash out....but, there's nopthing to do about the rear quarter.

If the hole in the dogleg is that big, there's a pretty good chance the same hole is in the rocker....only way to know is stick a screwdriver into the hole...if it goes in more that asbout 3/4", its going through the rocker also.

However, if the inside of the sills & the underneath are all solid, its just an outer rocker & dopgleg repair which is easy to do at home.
 
OK, so here are a couple more photos of the offending area. I cut the outer skin using my Dremel tool, and then broke off the rusty pieces of the inner metal with some pliers:

357595845_12f75e7a17.jpg


(Large version here: https://farm1.static.flickr.com/124/357595845_12f75e7a17_o.jpg)

I seemed to be cutting through metal, not rust, for the most part. You can also see some bare metal scratch marks I've made on the sill with a screwdriver.

Now (thank goodness for digital cameras ... I couldn't even see this by eye, but I was able to put the camera lens right up against the hole) a shot of the interior cavity:
357595946_0ca09eee5a.jpg


(Large version here: https://farm1.static.flickr.com/145/357595946_0ca09eee5a_o.jpg)

Comments? What should my next step be?
 
jjbunn said:
Comments? What should my next step be?
Click to expand...

Julian - that doesn't look too bad. The outermost portion of the rear outer sill is gone and so is the dogleg, but the inner looks Ok. Can you point the camera the other way (toward the front fender) and snap a few so see the condition of the sill bottom/castle rail?

You'll need to replace the dogleg anyway, might want to order a new one and carefully trace the outline then cut away the old area with a hacksaw blade. Just be careful not to take off too much.
 
OK Scott ... I'll take a couple more photos tomorrow, and post them.

Thanks! Julian
 
You have been liveing right, that's not bad at all.
 
Wow! You WIN!! Scott's right: it doesn't look like you've got structural damage! A "rust converter" chemistry and some "space-age adhesives" will have Harold up-and-running!
 
DrEntropy said:
Wow! You WIN!! Scott's right: it doesn't look like you've got structural damage! A "rust converter" chemistry and some "space-age adhesives" will have Harold up-and-running!
Click to expand...

Iffn this were my car, I'd drill a 3/8" hole in the inner "membrane" (the thing with the circle on it) and inject a cloud of steaming hot Waxoyl. Same into the sill cavity lengthwise. You will not have better access than right now :smile: Then glue at will.

Or maybe use the old wadded-up-rag-on-a-coat-hanger-coated -with-POR15 down into the sill abyss.

But I live on the right coast, which loves road salt.
 
Julian - go out and buy a lottery ticket right now! You are in luck, your inner membrane looks great. I would cut out the dogleg completely (get a new one first so you have a cutting template)and then cut out any rotten areas on the outside of the outer sill. Spray that open cavity full of Waxoyl or Penetrol. Maybe even spray POR-15 in there. Patch the inner sill with a 16 or 18 gauge metal patch with either welds or a good body adhesive, and then glue the new doglegs in place.

Have fun!

Jack
 
Not bad, Julian....so, it looks like you need a RH dogleg (457-580), outer rocker (457-160), & inner membrane (457-180)...you're talking around $175.00 for parts!! How's the other side though?
 
They likely "match." The dog-leg panel repair using Panel Bond adhesive or similar structural epoxy will work fine! Don't cut until you've the new panels in-hand, as stated before. I drilled and pop-riveted mine when bonded, stainless rivets and ground all down after the 'set'. Looks bespoke now.
 
Sorry but I am soon to start this same project and have a question

isn't the inner seal in the picture gone?
If so how can he replace it without cutting it out?
If not why is he being advised to make a patch or purchase the seal part number 457-180
 
gcan said:
Sorry but I am soon to start this same project and have a question

isn't the inner seal in the picture gone?
If so how can he replace it without cutting it out?
If not why is he being advised to make a patch or purchase the seal part number 457-180
Click to expand...

Yeh, I'm a bit confused as well, mainly by the terminology.

The innermost flat structure is the sill ... it appears to be intact to me, and I don't understand why it needs replacing. There is a very light amount of surface rust on it.

The outermost body panel is the dog-leg, and that has been cut back to solid metal.

Then there is an inner panel (the seal?) that is non-flat. That too has been cut back, not quite as much as the outer panel. It was the piece that was most rusted.

Now I have POR-15'ed inside and around the hole, over everything, and am waiting for it to dry.

I have a crazy idea: use some Touch 'n Foam expanding foam to fill the hole. After it's dried, sand/shape the outside surface to match, then use some metal meshing to cover, and then filler/Bondo over that.

Obviously that wont be as strong a metal, but I don't plan on kicking in that part of the car :smile:
 
Dont do it! Aside from the structural strength issues, ~ask me how sills hold up to a BMW @90 degrees and @ 40 MPH! They saved my rear when the door was pushed in 8" and the seat over 2"! Both occupants of the B walked away

The next time anyone has to go in there the foam will make life heck! You cant get it out and it burns with toxic fumes.
 
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