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MG MGA - Inner sill questions from Glenn

Hi Folks. As you have gathered from a previous post, my inner sills, and rocker panels are toast, and need to be replaced. To define inner sills, I mean the flat metal sheets, stamped "U channel" inner sills, and the outer rocker panels. My question is: Is it possible to replace these parts with the tub on the frame, or does the body need to be removed? I have inspected the vehicle, and it sure looks like the body will have to come off in order to install the inner sill flat plate parts. Glenn
Glenn

Glenn, I am about to start on this same project. From studying the photos on the Eclectic Motorworks web site it looks like it will be possible to replace the inner sills with the body on the frame, but it would be easier to prep these areas with the body off. Problem is that unless you have a body jig you need the frame to keep everything in alignment. The tough part seems to be cleaning the spot weld area on each end of the center inner sill panel where it attaches to the front and rear clips. If you can do that then the rest of it should be fairly straight forward. The upper frame covers on my car are in good condition so I don't want to cut them to separate the body sections and there is not enough strength in my sills now to lift the body in one piece even with a jig installed across the door opening.
Bill Young

Glenn, that work can be done with the body on the frame, and some would argue that is the best way to do it and maintain alignment/location of the sheet metal. The sill plate (using Moss' terminology) is the narrow horizontal piece that welds to the front body mount and the sloped rear deck near the battery access opening. It runs along the top of the frame rail, with a piece of foam between it and the frame. I left my foam piece in place when locating my new sill plate. The foam will be reduced in cross section quite a bit after years of installation. If you are eventually going to pull the body off you'll probably replace this with the rest of the body packing materials. The inner sill panel is the vertical piece between the doors. It welds to the lower inner fender panels front and rear. You will probably have to do some repair work to these areas as well, also possible to do on the car. The inner sill will also weld to the outside flange of the sill plate. The bottom of the inner sill should end up parallel and approx. even with the bottom of the frame. Do one side at a time, and take measurements from your remaining sheet metal if possible before cutting out the rusted sections.
G Goeppner

Glenn - I didn't do the work myself, but had a local body shop do the replacement of the entire A/sill/B section on both sides. They had to do it with the body still on the frame since we were pretty sure the body would fold in half due to the existing rust through both sides in that area. If you like, I'll send you a picture of the section as it looked immediately after pulling the body off the frame.
- Ken
Ken Doris

Hi Glenn,
I have read that you can and should repair these
sections with the body still on the car. Even if you plan to take the body off it is best to repair these first so that the body doesn't break into 2 pieces when you go to lift it off, since then everything will be totally lost. Also in place your body mounts will be holding the body sections in alighnment with each other like a fixture at least in theory. I wouldn't loosen them. Even so, what I did, after the experience of having to redo some of the new welds due to shifting while welding, was to put the fenders and door back on after the sill assemblies are tack welded in place and several more times during final welding to be sure that nothing has pulled or shifted. This is a pain in the neck, but can save you a lot of trouble in the end! Weld in short beads and move around to different areas to avoid too much heat in one area and shifting. I removed the guard (be careful) from my 4-1/2" disc grinder and used the back side of a cut off disc to get between the frame and the old spot welds to clean them up. Also do one side at a time (I know, its pretty hard to weld both sides at once!). What I mean is leave one rusty side intact while you do the first side. It will be extremely valuable for measurements etc. since everything is still in the right place. Then when the first side is complete move to the other side. If I think of anything else I'll repost. Will we be seeing less poetry now since you now have something to do this winter?
Good Luck
Ralph
Ralph

Definately body on. Try to remove the spotwelds with as little damage to the underlying panels as possible. This will preserve useable metal that might otherwise need replacement. My biggest challenge was replacing the base of the front panel immediately aft of the wheel well. I needed to do considerable shrinking to remove weld warpage even though care was taken to minimize shrinkage. A dent-pulling stud gun with a shrink tip worked very well.
BOL,
Doug
D Sjostrom

Glen,
The chassis is your body jig. It keeps all of the body sections in alignment. With the body off the chassis you have nothing to relate the front and rear body sections to each other during sill repairs. So unless your chassis has been twisted in a collision or rotted so badly that the body sags in the middle, do your sill repairs on the frame first then pull the body but install a brace from the front cowl to the rear and/ or across the door openings with a roadster. The roof of the coupe gives that shell a lot more rigidity so you don't have to brace it.

Frank
Frank Graham

Hi Doug. How the devil do you remove the flat sill plate that runs fore and aft from the front fenders to the rear fenders. This sheet metal piece sits perilously close to the frame, and seems impossible to extract without removing the body. Can you shed some light on how this piece is removed and replaced with the body still on the frame please? The outer rocker panel, and inner sill on the passenger side have been removed. I have been hacking away at what is left of the flat sill plate, but it seems to go between the door pillar, and another piece of sheet metal. Does this mean that spot welds holding the pillar to the body HAVE to be drilled out,in order to remove the flat sill plate? Sorry for the dumb questions, but this is new to me, and sheet metal replacement is not my forte. Thanks! GLenn
Glenn

Hi Ralph. Does THIS answer your question? lol

MGA Rusty Sills

A lovely car, the diminutive MGA
I drive mine almost every day

The B series engine purrs like a kitten
Or so some people have sometimes written

Handling and road holding are first class
Less agile cars, on curves it can pass

The boys at Abingdon really built her tough
Has withstood fifty years of weather and rough

Poor car’s coachwork and sheet steel
Really has held up pretty well, I feel

It’s a wonder of British engineering and design
With very little to complain about or malign

However, the MGA’s body is made of sheet steel
Many structural parts left uncoated with no paint to peel

Sill plates, and inner sills, to name just a few
On these thoughts your mind should chew

Unprotected steel will certainly rust
The inner sills will turn to powder and crust

You say just replace the inner sills
What about the mounting bills

For sheet metal parts, primer paint and a spot weld cutter
No wonder that under my breath, I am heard to mutter

Removing rotted metal parts is hard and dirty.
And remember, I am no longer thirty

Who says you can’t teach an old dog new tricks
These bloody rotted sills I do intend to fix

Kind MGA forum people give me lots of help
When on this internet forum, I do yelp

Of major structural repairs I am not a fan
But my attitude is, I must and I can

My MGA will again be made stout and sound
For another fifty years she will be around.


Written by Glenn Hedrich


Glenn

Glenn,
You're about to enter the dark side. This is about patiently drilling through the spot welds only through the layers being replaced. The key is finding all the spots and having a tool that can be controlled and manipulated to remove just the weld. I made my own out of a good quarter inch drill. Instead of an angular drill point, I sharpened it more like a ball endmill which allowed me to "walk" the cut around as necessary.

I didn't use all of the rear replacement component of the two pice vertical panel. Just enough to replace what was unsound. After cutting out the rot, I used the pneumatic punch/ flange tool to create a flange along the upper edge to recieve the edge of the repair panel cut and punched for mig plug welding.

I'm going to scour my photos and send any that may help. Most are fairly high resolution, so you should be able to enlarge areas of interest.

You'll get mail.
BOL,
Doug
D Sjostrom

Thanks everyone, and thanks Doug for the additional photos. I'm sure they will be worth their weight in Twin cam engines. Cheers! Glenn
Glenn

Glenn,
If you are as good at bodywork as writing poetry
your MGA will come out great! I especially like the line "And remember, I am no longer thirty"

Ralph
Ralph

Hi Ralph. Thanks for the kind comments. I was going to do a complete body and paint job on the old girl anyway, since it was last painted in 1980, when I restored it the first time. I'm reasonably competent with bodywork and paint, but am a newbie to structural repairs. Fortunately, I have a friend who is quite knowledgeable about such things, and who is willing to assist me with this tricky work. Cheers! GLenn
Glenn

Hi Glenn
Measure BEFORE you cut. Building door supports to wrong door opening will do nothing for you. Close enough is not good enough. Use piece of plywood to precise dimensions to see that the opening is corect and square.
Martin
Martin

Inner sill update. It is surprising how fast two MGA fenders and a door can be unbolted and removed! This chore was done on the passenger side of my 1500 roadster (working alone) in just uner two hours! Then, mainly all yesterday, I cut / ground /chiselled / drilled out the old rusty passenger side inner sill components, and my friend Terry fabricated gorgeous new inner sills, and inner sill plates out of heavier than stock guage galvanized sheet steel. Terry is a metal fabricator by trade, and is a true wizard with sheet metal! I have never seen anyone work so quickly, but so precisely) Today, we did an all day, no break "marathon", and replaced the passenger side sill plates and inner sills. When not helping Terry with the sills, (He did the welding) I fabricated new pillar bottom patch panels, which were MIG welded in place with no problems. The new sheetmetal sill parts he made fit very well, with just a bit of persuasion. (hammer and hydraulic jack) The front and rear fenders, new rocker panel and door can go back on the passenger side sometime next week, for fitting/adjustment. (After I recuperate a bit) 8^)~ Next weekend we will hopefully "marathon" the driver side inner sills. Weather permitting of course) It is hell working outside in the driveway. Definitely adverse conditions! Not surprisingly, replacing the inner sills IS a daunting and potentially perilous undertaking with lots of ways to go wrong! I am indeed fortunate that Terry is so experienced and competent at sheet metal fabrication and replacement! (Terry hand fabricated four new door pillars, and two inner sill sets for his 1600 last year)! Careful measurements and trial fits of my fenders, doors, and rocker panel along the way indicate that things should fit pretty nicely on final install. Thanks to everyone who provided input and photos as to how the sills are replaced. I am truly exhausted, so its a hot bath and then bed for this MG restorer! lol. Glenn
Glenn

Good work Glenn. Re the galvanised steel - does it MIG weld OK? No zinc fumes ?
Art

Hi Glenn,
Ask Terry if he would like an all expense paid vacation to Texas for a few days to get me off dead center doing my sills!
Ken

Hi Art. The sheet metal used was "satin coat" which I am told is lightly galvanized. The gasless, flux coated wire welder, (a Cheapie) worked extremely well and burned through galvanizing and light rust with no problem. Terry had initially scorned the cheapie Campbell Hausefeld flux wire MIG welder that I borrowed for the sill replacement, but at the end of the day, he was quite impressed with the little buzz box! There were some fumes, but we were working outdoors in my driveway, so they were not an issue. I am hoping to blitz on the driver side inner sills this weekend. Ken: If you are serious about the all expense paid trip to Texas, I will ask Terry if he would be willing to go, although I suspect his busy work schedule would make such a trip difficult to arrange. Cheers! Glenn
Glenn

Glenn,
I am quite busy right now myself but would anticipate doing something like that between Thanksgiving and Christmas. I have all the sheet metal together and have started one side but would like an experienced hand to help things go a bit quicker. Weather is nice that time of year and I know some great BBQ spots! If he has an interest just let me know!
Ken

Inner sill update #2. Well, Terry and I again blitzed on the other side of the MGA, and managed to install the new inner sills on the driver side, and to also patch a large section of rotted out rear (latch) pillar bottom. I also got one door and one rear fender (temporarily) bolted back on. The door latches well, and fender gaps look excellent. Both rocker panels are a bit too big, top to bottom, and will need to be trimmed a just a tad 8-( Other folks might not want to get rocker panels from Moss Motors UNLESS they are willing to modify them to fit. I have been repairing minor rust damage on fenders as I go, so the car has that primer splotch look. So I am now committed to a complete body and paint job next year. That's good, since the paintjob is 25 years old and well faded anyway. Cheers! Glenn
Glenn

This thread was discussed between 28/09/2005 and 10/10/2005

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