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Discussion Starter #1
The inner rocker panels on my 73 convertible need to be replaced. I am thinking about attempting the repair myself. I've been doing a lot of research in these forums and others and am looking for any information that members can share.

I am not doing a full restoration as my floor pans are sound. I've been told that a 71-73 replacement of inner rocker panels is actually easier than in earlier models. Any truth to that? Can I do this with the car on jack stands or is it best to do repair when the car is sitting on its suspension? I've heard arguments for both.

I'm currently dismantling the interior and am taking off the passenger front fender (doing one side at a time). I was told the passenger side is my worse side. I plan to replace the inner front fenders too. The passenger side is crap with a piece of metal welded in where the battery tray should be.

Any information, help, and suggestions would be greatly appreciated. Thanks.
 

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#1 - Use as many screw-adjustable jackstands as you can get a hold of to support the car so it doesn't sag when you're doing the work. - The inner rocker is actually your structural frame on a 'vert. Once it gets compromised by rust or you cut it out, the car will sag in the middle
#2 - Get a copy of the chassis manual for the factory frame measurements. You might have to 'preload' the car to get things back where they belong. Confirm frame measurements before and after you weld in each piece (torque boxes, front fender aprons, inner rockers, etc) because you definitely do not want to rebuild your car out-of-square!
#3 - A good MIG welder is worth it's weight in gold - don't go cheap!
#4 - remove all rustproofing/seam sealer before you start cutting/welding. When working on AlphaCat's rear wheelwells, the undercoat inside the quarter panels caught fire and I didn't catch it until it had already burned my power window motor and scorched my NOS door trim panel - DAMMIT!
#5 - if your inner rockers are toast, chances are your torque boxes and floorpans are too. Use the full-length replacement floorpans for a cleaner look
#6 - At least now there are '71-'73-specific floor pans available. Use them! I only wish they were available when I did mine!
#7 - Floor-to-rocker flange goes one way for coupes, and the other way for 'verts (one goes up, the other down - I can't remember which is which.)
#8 - Since the rockers are built onto the outer rocker, that takes up space inside the car. Remember that 'vert floorpans are narrower side-to-side.
#9 - The replacement inner rocker pans are Mustang pieces, and are a bit short for our longer Cougars. You'll need to be creative at the back end.
 

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Discussion Starter #3
Thanks for the information. I'm slowly dismantling, photographing and labeling all the parts as I go. I've got the passenger fender off and beginning on the interior.

I have 6 jack stands and two 3 ton hydraulic jacks. I can already see a narrower door gap on the passenger side and some slight paint damage where it rubs. I've got the manuals and will look for the measurements. I was told the floor pans look good, but haven't taken the carpet up completely yet to check for myself. How can I tell if the torque boxes need replacement too? What can I do about the shorter rocker panels? I bought rockers from Mustangs Unlimited which are 77 inches long.

Can I do this with a MIG flux welder and not use gas? I'm reading that this is mostly spot welds too.

I'll be picking your brain if you don't mind. Thanks again. Tony
 

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I have a set of four of screw jack stands similar to these which are a much better choice than hydraulic bottle jacks for holding something in place. Bottle jacks and/or hydraulic floor jacks can leak down over time. They are meant to be lifting jacks, not 'holding' jacks'. The screw jacks can't move once they're set.

I've never used the flux wire for welding. Not sure of the flux welder's ability to weld thicker gauge metal like the torque boxes and inner rockers. I've always used the Argon gas when mig welding.

If the torque boxes need replacing, you'll know once you start cutting the inner rocker loose since they have tabs that are welded to the inner rocker. If the torque boxes look the least bit rusty, replace them. Remember that they're structural, carrying the load from the front framerail to the outer frame (aka inner rocker)

The Mustang inner rockers will work, but they're short. You'll have to figure out exactly what to do yourself since I've never replaced them on a Cougar. Probably just need some thick gauge metal to make up the difference - not a problem if you can weld.

When we did my buddy's Mustang 351C-4V Q-code 'vert 25+ years ago, we didn't 'spot weld' per se, but made welds about 1-1/2 to 2" long, skip an inch or so then another weld bead, and so on... at the front and back of the inner rockers where you're welding to the front and rear torque boxes, we used continuous welds.

You will need several pairs of Vice-Grips, including some of the deep-throated c-clamp style that can fit over large irregularities.
 

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Discussion Starter #5
I've been reading everything I can get my hands on regarding bodywork, welding, etc. Can I do this with the doors in place? I'm thinking I have to buy / make a pair of door braces as it is a convertible. If I were to support the car with jacks will that be enough. I don't want to take a chance of the body flexing too much either. I'm trying to do this without taking the entire car apart. I am leaving in the engine and most of the other major components.

I have 6 jack stands, not bottle jacks to support the car, but I can look for screw jacks like you show. I have two floor jacks to lift the car. I have the factory manuals as I wanted to look up the correct measurements but am having trouble finding the information. The inner rockers that I bought from M.U. are 77 inches in length. Of course, last night I found Ken's Cougars and it states on his website that he has the 'correct" size and shape 71-73 Cougar inner rocker panels.

I have most of the interior removed. The passenger side has holes in it, however I can't see the front torque box. The driver's side looks like someone tried to patch it with thin metal and rivets.

I am assuming I will probably need to replace the torque boxes too. I can't seem to find the right ones for a 71-73 Cougar. M.U. has 67-70's which state they can be modified to fit. Anyone know of Cougar-specific ones out there?

Thanks again. Tony
 

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Our Cougars share frame/floor sheetmetal with Mustangs for the front 2/3 of the car. That means everything under the skin from the radiator support to the rear floorpans. From the seat cushion pan on back our Cougars are longer so that's where they start to get 'Cougar-specific' - rear framerails, trunk floor, trunk dropoffs, rear springs, etc. So to answer your question, there is no Cougar-specific front torque box - just use the Mustang convertible torque box. Same with the floorpans.

For your frame measurements, I know I've seen them in the '72 Body & Chassis book, since that's where we got the dimensions for my buddy's '73 Mustang 'vert. If you can't find the figures, PM me and I'll try to scan the proper pages from the manual for you.

Having the doors in place will not help hold the car in place, but it will help you with some idea of the proper door gap when the car is jacked up the right amount. Bear in mind that it will sag a bit when you put the car back on it's wheels, so you actually want to hold the car a teensy bit 'too far' when you are welding in the new parts.

Another thing you might want to consider is welding in some subframe connectors. Yeah, they're not factory, but they will help stiffen the chassis. My buddy regrets not adding them to his 'vert when we did that resto 28 yrs ago since his car jiggles a lot going down the road. While not exactly driving like a bowl of jello, you do notice the body flex. You definitely don't want to have your finger in the rear door gap when it is going down a bumpy road! Anyway, if you look at the pics in the 'My Gallery' link in my signature below, you can get some idea of how we did the subframe connectors in my '73 Hardtop (more for limiting body twist when dragracing than anything else). They weld to the front subframe, and then immediately angle over to a point where the rest of the connector goes straight back to meet the rear framerail. Yes, they are semi-inletted and welded into the front seat pan and rear floor (and on a 'vert they'd also be welded to the additional front floor cross bracing), but that helps give the car a lot more structural integrity. You could leave the connector hang below the floors, but then they're more noticeable from the side, and wouldn't tie the car together as well.
 

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Discussion Starter #7
Thanks I will look into the subframe reinforcements. The car makes a lot of noise when going over bumps in the road, but now that I know that the inner rockers were rusted out, I think that may have been the cause for all the noise.

I've got the interior out, but was thinking I may try my hand on replacing the inner front fenders first to work on drilling out and then welding spot welds. I contacted a vendor for the inner rocker panels and he tried to talk me out of doing the inner rockers myself. It put some doubt in my mind that I could do this. However, reading the forums and getting information from everyone has really helped me to decide to give it a go.

Still have to order torque boxes and figure out how to make 77 inch rocker panels into the right size for the Cougar. Adding metal to the end will keep it structural sound?

Thanks again,
 

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Discussion Starter #8 (Edited)
I have most of the interior removed now. Below are pictures of under the interior trim rear quarter panels and holes that are there. Behind the passenger side, it looks like someone riveted a can there and painted it to hid the rot. I found some fiberglass there too. Looking at the pictures can you tell if the torque boxes need to be replaced too? Should I dig further back?

IMG00358-20110924-1106.jpg IMG00361-20110924-1115.jpg
 

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Discussion Starter #9
Here are a few more photos of the inner rocker panels and a couple of photos from under the car. The inner passenger doesn't look too bad. The driver side has been riveted with some thin metal. In another photo (rear passenger inner rocker panel) you can see the paper that was stuffed into the cavity of the rocker panel so that fiberglass could be put over it. Nice.

Can't tell about the front torque boxes yet, but I figure that since I can see inside the rocker panels in the rear, the rear torque boxes probably have to be replaced. I have photos of where the front rocker panel goes into the firewall. Both side looks pretty solid, but I still plan to take off the front fenders to check them.

driver closeup.jpg driver side rear.jpg Driver side.jpg Pass side.jpg rear rocker panel.jpg
 

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Discussion Starter #10
There's a lot of loose rust all over the floor pans. I'm going to vacuum it up and scrap off the old padding, etc. to get a better look at what's left. Like I've said before the rest of the car seems to be in really good condition, I can't believe all the loose rust.

Hard to tell about the front torque boxes still. I've begun to remove the front fenders, I think it will give me a better view of the front torque boxes. The rear ones (as shown in the last group of pictures) look bad.
 

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...#7 - Floor-to-rocker flange goes one way for coupes, and the other way for 'verts (one goes up, the other down - I can't remember which is which.)
#8 - Since the rockers are built onto the outer rocker, that takes up space inside the car. Remember that 'vert floorpans are narrower side-to-side.
#9 - The replacement inner rocker pans are Mustang pieces, and are a bit short for our longer Cougars. You'll need to be creative at the back end.
A couple of comments (from someone who has done this job on a '69).

#7, unless there was a change in construction in 71-73 (from 69/70), there are no flanges on 'vert floorpans to rocker, the floor just ends at the rocker and attachment is done to the bottom of the inner rocker (as opposed with a flange (down) to the pinch weld on a HT).

#8, vert floorpans are not narrower, they just don't have the flange. BTW, some (if not all) of the repro pan pieces I recall having the flange facing the wrong way (up as opposed to down), unless I am remembering the repro trunk drop-off pieces, their flange at where they join is the wrong way. Even that may be Cougar specific observation because Mustang had the trunk drop-off reliefs going one way (out or in) and Cougar the other.

#9, inner rocker repros are sold at 68-73 Mustang, so my observation should hold (unless 71-73 was longer, which I doubt). The observation is that the Mustang inner rockers are not shorter, my (MU) rockers fit in place of the original '69 rockers no problem with length at all. What there is problems with are missing tabs (for torque boxes and the like at the front end (append old pieces to the new to solve this problem), incorrectly located seat belt anchor points, no flange on the back end, no angled end at the back end (correctable for the most part by flanging what is there to make the end angled).

A few other helpful hints.

Leave the doors on, they are very helpful to see how things align before you take it apart and how you want things to look afterwards (unless the body is already out in which case corrections are needed).

Leave the top frame on, use it to help hold/support/complete the unibody structure, like the roof on a HT does (albeit not as strong).

I did the rocker job on a lift, where I extended the lift arms as far as practical (beyond the stops, but still within what I felt was safe). By doing this, I was able to support the car at the LCA attach points in the front and under the leaf shock mounting plates at the rear. I had no change in the door gaps with the rockers/torque boxes out from where they were with the rockers/torque boxes in. However, I had the engine/trans out. If you are leaving them in, support will be more important. I recommend the engine/trans be out, perhaps check with Tom at KTL and see what he thinks (see below). BTW, Tom sometimes does the rockers without changing the torque boxes, he just sections what he needs apart to get access to the rocker to torque box attachment points and R&R's, then closes the box back up and welds it back together.

I highly recommend that you study the beginning of my ECI thread in depth and detail for most everything you will want to know about this job. For anything not answered to your full understanding, get in touch with me, I am always happy to help a fellow ECI. You could also call Tom at KTL restorations (look it up on the interwebz), Tom is very knowledgeable on this job.

Regards,

Bob
 

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Discussion Starter #12
I vacuumed all the loose rust up, scraped off what I could and there seems to be a lot of surface rust. The metal still seems to be in pretty good shape. No rust through on the floor pan.

I'm posting pictures of the front passenger inner and outer torque box (removed front passenger fender). The other photos are of the passenger floor pan and what looks like a repair to the rear passenger seat belt area. How do they look to everyone?

I'm having trouble removing the seatbelt bolts. Any suggestions?

Pass front torque box out.jpg Pass inner torque box.jpg Pass rear repair.jpg Passenger floor pan.jpg
 

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Discussion Starter #13
With the passenger fender off, I plan to replace the front inner fender apron, the battery tray was a welded piece of metal. There is a rust hole in the shock tower area, however the rest of the shock tower is really solid. Once I remove the old front inner fender I'm going to see how much patching I can do.

Harbor Freight has their 90 amp MIG Flux wire on sale this month, with the coupon in R&T magazine it's under $90. Worth it? I've read different opinions on their MIG. What about the spot welder gun they sell? It looks like the one sold by Eastwoods. Has anyone used it? Thanks again.

pass upper rail.jpg close up pass upper rail.jpg
 

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From what I can tell in your pictures.....your torque boxes are looking good and your floors are looking decent.It apprears to me that your main rot is concentrated to the rear section/portion of the inner rockers along with some corresponding rear floor/platform metal(behind seat belt anchors). So,if thats the case do you really need to replace the whole inner rocker panels and floor pans? I would only remove the rotted areas of the floor to gain access to the rotted section of the inner rockers and repair/replace metal from there. Again,only do one side at a time to retain your structure of the car. Keep us posted.
 

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Agree with Fousty. On the welder, this is one of those things I would not buy from HF. Granted you will never find something as cheap but with certain tools you get what you pay for and being dollar wise and pound foolish is not the thing to do with a such a tool purchase (IMO, FWIW).

For removing seat belt bolts, you need to pick up a good quality Torx driver bit in 3/8" drive minimum, preferably 1/2" drive. Lisle or other quality brand.
 

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Discussion Starter #16
Started to drill out the spot welds on the inner front fender. I bought a spot weld bit that is supposed to cut out the spot welds but I'm finding it kind of hard to use. I went through both pieces of metal on the first couple of tries. The bit isn't lasting long though.
 

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Discussion Starter #17
an update as to where I am; finally got the front inner fender out and I am in the process of cleaning the area. I'm finding that I don't have a lot of time to work on the car during the week though, not as much as I seem to want to anyway. Some of the photos show the old battery tray that someone had welded into place sand my handy work on cutting out the welds.

Old Battery tray makeshift.jpg Getting better at cutting spot welds.jpg RH IN Fender front disconnect.jpg RH inner fender almost out.jpg RH inner fender out.jpg
 

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Discussion Starter #18
I can only add 5 photos per post, so here are some more;

Under battery tray 1.jpg Under battery tray 3.jpg Old battery tray.jpg

The rust through is part of the inner fender. What a mess. Slowly getting through this, of course like everything else, destruction is easier then construction. :)

Thanks a gain everyone for the advice.
 

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Discussion Starter #19
I've been busy at work so I haven't much time over the past week to work on my car. It's starting to get cold at night here in NH, so I am making space in my cellar to store the parts I've taken off so far. I have a rim blow steering wheel that I would like to restore and a full dash I bought years ago on ebay that was in rough shape. I still have the original leather seats stored and want to repair them so that I get rid of the vinyl ones I bought years ago that I put on. I'll have to go through the seats as I don't remember how bad the rips were.
 

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Discussion Starter #20
From what I can tell in your pictures.....your torque boxes are looking good and your floors are looking decent.It apprears to me that your main rot is concentrated to the rear section/portion of the inner rockers along with some corresponding rear floor/platform metal(behind seat belt anchors). So,if thats the case do you really need to replace the whole inner rocker panels and floor pans? I would only remove the rotted areas of the floor to gain access to the rotted section of the inner rockers and repair/replace metal from there. Again,only do one side at a time to retain your structure of the car. Keep us posted.
That's what I think I am planning on doing. I am going to start with the passenger side and replace the rear torque box. I bought the inner rocker panel from MU for the 73 convertible. I'll cut it to length from the end of the front torque box where the metal is good, since the mustang panel is shorter, patching them together with some reinforcement. As I stated before, my garage isn't heated so I'm going to try to do a lot of stuff in my basement workshop to be ready for the spring. I ended up picking up a craftsman MIG / flux core welder. It was on sale a week or so ago. Been playing around with it to get the feel of it on some of the old metal I took out already. Thanks all.
 
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