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MG MGB Technical - Sill Replacement questions

Hello All.
At long last I am at the stage of replacing the sills in my mgb roadster. I have the front fenders off and have cut away the outer sill under the door. I am using the Linsey Porter book for reference, which by the way I find only somewhat helpful.

Question 1: How is the castle rail attached to the floorboard, and what is the easiest way to remove it? Ever book I have on the subject always shows the castle section already removed ready for the new one to be welded in! On welding in the new... The Porter book shows it being tack welded from the inside. Then what? Is that it? Are any welds placed on the outside of the castle rail to the floor board? BTW, I have a small MIG welder only, and plan on using plug welds for sill replacement.

Question 2: The Porter book also does not mention how to remove the inner membrane from the back of the car where it gets "fatter". Are there spot welds here, or some kind of seem weld? Also of interest is the front of the sill forward of the A pillar. It looks like the vertical panel (inner fender) is flanged at the bottom so that the outer sill it "tucked" under it. Do these spot welds have to be drilled out as well, so that the sill can be "pulled out" from underneath? Again, the Porter book makes no mention of this area. The pictures could also stand to be a bit clearer... In the book, after the outer sill is welded in, it says something to the effect of " See how much wider the inner panel is thus giving a good surface to weld to.." HUH? Does the inner membrane get welded to the OUTSIDE of the vertical inner fender panel? I certainly can't tell by the picture in the book.

I want to be able to clearly see the steps involved before I attemt to "figure out" on my own, and make more work for myself than necessary.

I have been following these posts for a number of years now, and I know there is a wealth of information to be had from experienced MGB restorers. I just need some specific tips from someone who's been there and done that.


Thanks.


Confused in Colorado.
Scott Wooley

Answer 1 - the castle rail is spot welded to the floor - clean up the floor to find the welds and drill them out. At the ends you need to drill out the welds in the vertical sections of the rail.

When welding in the new rail, just plug weld through the holes left in the floor panel when drilling out the original spot welds. No need for external welds under the rail.

Answer 2 - yes the vertical membrane is spot welded to the inner fender and the rear panels as well - just work your way round the edge of the old panel and drill out the spot welds until the old panel will drop free from below - again , when welding in the new panel just plug weld through the holes.

New holes will have to be drilled where you replace both panels e.g along the bottom of the castle rail / inner membrane/ outer sill joint. For the top joint of inner sill/membrane/ outer sill I prefer to run a seam weld in the door opening and grind flush to provide a good seating for the door seal.

Before final welding - make sure you refit the wing and door and make sure all the panel gaps are OK - especially the rear door gap which will taper if the body has sagged or bucked - adjust by jacking up one end or the middle to get it all correct - once welded up it will be set!
Chris Betson

Chris, you make it sound so easy!;-#...
Chris Cooper

I was just thinking the same ;)

Tatty

Hi
If the castle rail is shot in my experience the edge of the floor is usually not much better, you used to be able to get a repair section for the edge of the floor, don't know if its still available
Ron
r algie

Look for the book "Practicle Classics on mgb restoration". Also a good reference. Make many measurements before taking all the old steel out so you have a reference when you start putting new steel in. Digital pictures or video may help. Take your time. I'm on my third job and I'm self taught.

Look at www.mzaff.com , he has some good pictures.
Kirk Knutsen

I don't know who mzaff is, but I sure like the pictures he has, Thanks, whoever you are.
Derek Nicholson

Thanks for the plug Kirk. Scott, Follow Chris' advice. Derek, I'm glad the images are helpful.

-mike
Mike Zaffarano

Scott

1) The floor panel is welded to both the castle and the inner sill edge. The castle is welded to the botton of the inner sill edge and the floor. There are two rows of spot welds, you may have to scrape away some seam sealer, floor mastic, and undercoating to see them. I usually replace the entire floor, but if you want to keep the floor, you have to remove the spot welds with more care.

Use a drill to remove spot welds. Then use a 1" putty knife (one where the metal extends through the handle) to split the panels apart. I used an air chisel/sawzall to cut away most of the castle, leaving just the spotwelded edge. This makes it easier to drive the scraper between the panel.

As Ron said, if the castle is rusted, the floor has problem areas too. The castle section difficult to remove, has a lot of welds, many of which are welded to thinner panels like the floor and footwell.

2) The best way to cleanly remove the inner membrane is to cut away as close to the vertical edge that is between the side panels. Drill out the spot welds, then drive the scaper between the panels.

I'm at work now, but I can send you pictures I took last month when I removed the castle/inner membrane/outer sill from my 72 BGT.

Rich
Richard Stinchcomb

I forgot to mention, before removing the castle section, I measure the distance between the botton edge of the castle rail (where the inner membrane and outer sill are welded at bottom) from both sides of the car. This way the new section can be put in place and some original point of reference is used to put it back. The measurement is taken near the front on the castle and also at the rear. For some reason they can be different.
Richard Stinchcomb

Wow, you guys are awesome. Chris, you should write a restoration book and put Porter's to shame...
As far as my car goes, the castle rail is being replace due to some small rust holes at the front. The floorboards are perfect. The inner membrane is full of holes, but nothing like it shows in the Linsey Porter book. The drivers side castle rail looks to be fully intact with no rust through. Would it be wise to try and save this rail and replace only the rusty inner membrane? I ordered all new Heritage or Steelcraft panels in advance for both sides. Would it be difficult to seperate the inner membrane from the castle rail without destroying it? I could always put the new, unused rail on ebay...

Oh, I almost forgot. All of the panels I received from Moss are Heritage or Steelcraft with the exception of the passenger side dogleg. It is a red primered Taiwaneese made piece of s---. It does not fit the body at all. I used this panel as a "rough" guide of where to cut off the rear dogleg and as it turns out, I need about 3" more height in order to be able to remove the sill! What a piece of crap. I'm going to return it, but I would like to be able to cut out the rear sill in the meantime. Is there a safe measurement to use when marking the horizontal line used to mark where to cut out the rear dogleg, other than holding up the replacement panel? I'm guessing that Steelcraft or some other company makes a correct fitting dogleg panel. Anyone else had this problem? Where can I get a good fitting panel?

Thank you so much for all who have replied to this post so far. You are all of great help.

Thanks.

Scott
Scott Wooley

Scott,

Motorhead in VA. Ask for the black panel not the red one. They will go out of there way to find the proper one for you. Helped me, as I had the same problem.

Check their website.

http://www.motorheadltd.com/

-mike
Mike Zaffarano

Hi All,

I am going to be doing a full body restoration on a GT this summer and will do a photo record of it - like the engine rebuild one on my website. It will cover full sill replacement and floor panel repair as well as front wing replacement and door skinning, plus rear chassis leg repair and rear valance repair

Like most things on MGs they are really simple once you know how they are put together....
Chris Betson

Scott:
Take a look at www.paneldoctor.com. A nice picture guide of what your going to be doing. I found it helpful.
Kirk

PS: Hi Mike, hope your well.
Kirk Knutsen

This thread was discussed between 15/05/2003 and 16/05/2003

MG MGB Technical index

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