MGB: Rocker Planel Replacement Advice

Hello all

I need some advice about how to determine if I need to replace the complete rocker panel assembly in my ’71 B. Currently I have rust in the typical places you would expect; rusty floor pans, rusty lower quarter panel section and dog leg panel behind the door. In most cases the panels are not rusted completely through, so I can’t see what is behind the panels. The driver’s side dog leg panel does have a hole in it and through the rocker but the inner panel looks like it’s solid. There is a small 1/8” hole in the driver side sill and some pitting.

I don’t think I can afford to pay someone to restore the car and my research into replacing the rocker panel assembly may be above my novice ability. So my question is, if I’m prepared to replace exterior panels my self, can any one give me step by step instructions on best way to approach removing and determining how bad things really are? I’m trying to avoid starting something I can’t finish. I realize the best thing is to get all the body work done now but I can’t really afford it at this time and I don’t want things to get worse. How do I buy time?

Any advice would be greatly appreciated.

Regards

Chris

Hello Chris,

It is not an easy or cheap job to do correctly. And then you'd want to paint it to match or paint your whole car, so altogether it's not a small project. I have three little kids which means I have pretty much zero money to spend on "non-essentials" like body work. Your car will not fall apart any time soon. Nor will it be a safety hazard. The damage is already done, so you can put off worrying about it until it starts to be a real eyesore or your car starts to sag in the middle (hard to open and close doors). It's a nice thing to fix it, but you don't have to do it now if it's not a financial or time priority for you.

If you've got lots of money and/or time and skills then go for it. If not, just live with it and enjoy driving your car. :)

Chris,
What would be most helpful to us would be some good photos of the areas you describe. There are rusting problems, and there are rusting problems, and until we can make a visual assessment of the extent of your rusting, most of our responses will be far more guess work and generalization than will do you any specific good.

now in the dead of winter if it needs it "get er done". The rockers and floors are the center of the car and its strength. I recommend a pro and it will do you well to round up the needed parts and all he charges is labor...when it is all put together spray the hell out of it with POR 15......and it is good to go for 20 plus more years. You should spend your hard earned money only once, so get quality.

Chris, you can see what is involved at mgownersclub.co.uk There is an article there on replacing sill/rocker panels.
You can do the work yourself,but it isn't exactly easy.

Stuart.:beer:

Having done both partial and complete rocker replacements several times I can see why having it done by a pro is going to cost $1,000-1,200 per side.
The first time I did it I had tons of previous experience doing a lot of minor body repairs and painting but never took such huge chunks off and replaced them.
A key to this job is welding in cross braces ( or alternatively making a turnbuckle type fixture-see below) in the door opening and remounting the doors at every stage to keep the best alignment and shut lines. Also always tack the pieces on first and trial fit the doors BEFORE doing the final weld on.
Even then there was a fit problem with the Steelcraft outer rockers and both sides had to have a "patch" if 1/4 inch steel welded and blended in to get the gap to line up by the front fenders.
It is possible to partially relplace the inner and center reinforcing parts if only the ends are rotted. This will also lessen the tendency for the body to sag or twist which it will try to do if all the pieces are removed at once. You are going to have to remove the outer rocker to assess the condition of the center and inner pieces so it will require complete replacement most likely.
This means removing both front fenders and cutting off the rear doglegs. Then it's just a matter of drilling out the spot welds and chiseling the panel off being carefull not to wreck the castle mount which is at the bottom front of the door opening.
If you decide to tackle it PM me and I will forward the file I have showing the turnbuckle door fixture which allows for fine tuning the opening. It would be a great time saver from what I can see but I always did it the hard way!LOL
Anyone else need the drawings and pics just let me know.

Step by step advice? Sure.

I've been slowly going through this, and I've tried to cover it in my journal. Feel free to take a look at http://www.mgexperience.net/journal/Steve+Lyle/2377.

First thing is to assess the damage, decide what you want/need to do, and schedule it given time/$ constraints. I agree with the above advice you've already gotten - it doesn't sound like you've got an imminent issue. You've got something you'll need to address at some point if you want to keep the car 'forever', but when that 'point' is, is up to you.

Do your research - get an understanding of the parts that make up the MGB sill, and then assess what you can externally. If your inner side member (ISM) is bad, you'll be able to tell from inside the car. Any rust holes in the forward area of the ISM, in the footwells, under the carpet or rubber covers? The bottom of the sill is the castle rail, check it out thoroughly from underneath the car. If those two aprts are solid, you've got lots of time.

The remaining two parts that make up the rocker assembly are the inner membrane and the outer sill. Rust generally starts eating away at the portions of the outer sill that are covered - the rear dogleg area and the fwd area under the frt fender. Once it eats through the outer sill (and usually the fender/dogleg at the same time, which is what you're seeing) it'll start working on the inner membrane. Once through the inner membrane, water/dirt/salt/whatever will get into the box section formed by the innser side member/castle rail/membrane and feed the rust bug, and that's what you don't want to happen.

There's a good chance based on your description that the rust is limited to the fender/dogleg/outer sill. That would be good news, since then you'd 'only' need to replace the outer sill/dogleg/lower frt fender. If you fix it at this stage, you'll save yourself some time and $'s.

If you're going to do this yourself, you'll need metal working tools (a couple of 4.5" angle grinders are critically important, plus a drill, BFH, panel separate (an old butcher knife works well), and drills/grinding & cutoff wheels. And a MIG welder. Also, if you do it yourself you'll join a long list of people that started their bodywork experience (and maybe ended it) with an MGB sill repair (i.e., if you've got some basic mechanical aptitude, you can learn 'on the job' on your car and do a passable job - it's been done before, lots of times).

There are lot's of "how to do its" for this job available on the web - Google "MGB Sill Replacement", or "MGB Rocker Replacement", and start bookmarking sites.

To be honest, it does not take a tremendous amount of skill to do this job. It is not like you are doing any metal shaping, since the panels are pre-formed.

What it does take is a LOT of work and patience. You are going to use a hand-drill to drill out about 1000 holes by the time you get the old panels off. After the first 100 you will get the hang of it. Then you are going to drill anothr 1000 holes in your new panels and spot weld them by the time you get the job done. Working in the footwell area is a joy to be experienced!

It takes about 100 hours to do the job. You need a MIG welder, a drill and at least one grinder (I keep 4 angle grinders loaded with various abrasive devices).

When you are done, it is very satisfying.

If you post up some pics, we can better advise you on how to proceed.

Here is a link to one I am doing now. It is a non-traditional approach in that I only replace the lower halves of the rocker and inner membrane. The car was a southern car and did not have the horrible salt residue damage that we get in Ontario, hence this worked well. http://www.cardomain.com/ride/3385137


Pete

I'm at the beginning of this process.I agree with all of the above and have another 2 cents to throw in. First I went to Lee Millers site Millers Garage.com and studied his resto projects. He obviously took great pains to document this process.It's a great reference. Also don't cut ANYTHING off the car till it's properly braced, AND you have parts in hand. Mine are due to arrive tomorrow. It's been hard to wait, but while accumulating parts and supplies, I've been studying and asking LOTS of questions here and elsewhere.There's alot of people on this site that have done this job, and all are willing to help with advice and guidance. Most of all enjoy the process it's supposed to be fun remember? :)

Nothing to add - only agreeing to the good advice laid out by others. I'm in the middle of replacement of the L/H side, myself. We'll see how it turns out.

Thank all for the advice. Here are few shots of the driver side. It's hard to tell but the rust behind the door is though the rear rocker as well. It sounds like from the advice, I don't have an immediate structural problem. I would like to stop what ever rust I can and attempt replacing the dogleg and lower front quarter panel. Is it silly to put my time into this? Is there enough good metal to reattach to?

Thanks

Chris

Chris:

I guess you need to have a hard look at what you want out of the hobby. Some people just want to drive an MG and or tinker with the mechanicals. Others here will only feel that they have earned their stripes, and deserve to drive the car, after doing a full nut and bolt restoration. What is your need from the hobby?

If you have a look at the link I posted, I show how to do a full repair of a rocker withoud doing a full replacment of the inner sill or upper part of the rocker. I also show the dogleg (area in your picture) being replaced.


The car you show could be left alone and driven for years. A cosmetic repair can be done with fiberglass and putty and only you would be the wiser. Proper repairs can be done later if you decide to make it a priority.

Pete

Chris,

A lot of good advise already given. it is hard to tell from your photos how bad it is. Your description makes it sound like it is more of a cosmetic problem, but without seeing behind at least the front fender, it is very hard to tell. I suggest you remove the front fenders which is quite easy to do and see what the outer sill looks like. if you are lucky, it won't look like mine. The photo below is what was lurking behind my front fenders. i have also attached a link to a series of photos documenting my replacing of the complete LHS sill assy which I have almost finished. As mentioned, bracing the shell is key. My bracing has worked out well. All my panels, front fender, door, rear fender and outer sill line up almost perfectly without any adjustments! I attribute that to the strong bracing.

Ryan

http://cid-b45ae784d720d270.skydrive.live.com/browse.aspx/LHS%20sill%20and%20floor