MGB - floor pans (Part 3)

Continuing the effort of replacing the floor pans. In Part 1, I talked through decisions about parts and methods. In Part 2, we removed the old pans. Today, we focus on prepping the new pans and getting them welded in.

Context

paint from below, p-side

Remember that the original pans were spot-welded to the rails. This was done at the factory where very long spot-welder arms are available and things like the doors, dashboard, etc aren't yet installed, so there are fewer obstacles. Even with some crazy-long spot welder extension arms, you will not be able to avoid another solution for some of the mounting locations. Your options: seam weld from below or plug weld from above. At least on the right side, the wires, tubes and cable make a seam-weld from below option very difficult. Most do-at-home folks go the plug-weld route. The folks at British Auto Works in North Plains run seam welds around the outer edge from above, but plug weld the inner frame rails. If you're going to do this, they recommend running beads that are about an inch long and space them every couple of inches to prevent warping. It will hold at least as well, if not better, than plug welding the whole thing.

Fitment

p-side pan prep

The passenger floor fit like it was supposed to fit. It literally dropped right into place. It wouldn't shift too much side to side or front to back, but my hammer/chisel work bent some of the edge along the transmission tunnel, so I had to work the metal back into shape. Once the floor was stable (no wobble or weird clunks from my stepping on it), it was ready to go. The driver (left) side, however, did not fit right. The front right corner on the pan assumed the floor had a squared-off point to it, but my floor had a rounded edge. I had to bend the corner of the pan to test fit and then cut it off with my grinder for welding it in. It would not naturally sit flat either, so I had to be extra careful as I did my first few welds to get the floor to hold flat. You may experience a similar situation, even with the OEM pans. We know the aftermarket ones don't fit without cutting, so be advised.

What's a "Plug Weld"?
A plug weld is performed by drilling a hole through one material, setting that on top of a second piece of material and welding the two pieces together through the hole. In our case, we are making 1/4" holes in the new flooring. The weld is formed by setting the MIG wire into the center of the plug hole, pulling the trigger to start forming a puddle and then extending the puddle into the floor after the puddle has started to grab into the frame rail. Before we can weld, we need to poke holes in the floor, but where? I tried 2 methods. I'll explain them next.

Option 1 - Paint and Measure
Once the frame rails are clean, you just can't help yourself. You just have to drop the new floor on there and admire how nice it looks. It looks so pretty. Looking at the passenger-side pan sitting there, I wanted an easy way to spot the holes. I fiddled with the pan to make sure it was exactly where I wanted it and then set some tool boxes on top so it held still and firm on the rails. Then, I grabbed a can of white spray paint, slid underneath and spray-painted the edges of the frame rails where they met the underside of the new pan. When I lifted the pan off the rails, there were clear white lines showing where the frame rails were. I ran blue tape along those edges and marked drill holes every inch or so with a sharpie. The p-side prep picture on the right shows what the prepared pan looked like.

Option 2 - Use Old Flooring

using old floor, d-side

When I removed the driver (left) side floor pan edges, I didn't crumple them up as I went. Instead, I would separate a section and then cut it free with tin-snips when the trim started getting in the way. Once all of them were free, I arranged them on the ground with the larger sections I had cut out earlier. With the puzzle so completed, I could see where the old spot welds were. So, I arranged the puzzle onto the bottom of the new pan, and shot spray-paint through the taped-on floor-pan edges. When I removed the old edges, I had dots showing me where to drill the plug-weld holes.

Drill Baby Drill
Regardless of which method you choose, drilling the plug holes is a two-step process. First you drill a pilot hole and then you drill out to 1/4". I suppose a step-bit would work so that would be only one drill effort. Similar to cutting out the spot welds, this is time consuming. I understand why British Auto Works (and probably most other shops) reduce costs by seam welding the outer edges. For that reason, I drilled plug welds into the floor to correspond to the inner frame rails, and only a few around the outer edge of the p-side pan. My paint-from-below method worked pretty well, though my alignment slipped a little bit and I had a few holes that didn't align with the rail.

On the driver (left) side, I chose to plug weld the whole thing, so that meant more drilling on that pan. The holes I produced with Option 2 were an exact match. They aligned on the rails perfectly. Unfortunately, the holes that cut all the way through the frame rail were now completely exposed as well. The drilling out of a single pan took me 2-3 hours and overall there really wasn't that much of a difference in time between the two sides, even though there were far fewer holes on the p-side. That doesn't math-out logically, but that's what happened. The all-in time at this point is over 14 hours and no pans are welded in yet.

Plug Welding

If the grinding was the best part of Part 2, then the welding was the best part of Part 3. I borrowed a 110V Lincoln MIG welder from my wife's sister's boyfriend, and bought a small 20# tank of "steel mix" gas for the project (cost me $100 for the tank plus gas-fill on craigslist). I've heard these small tanks have 6-8 hours of gas in them, so that should be enough for multiple pan replacement projects. Once I had the passenger side ready to weld, I hosted my wife's sister and her boyfriend for a welding party. The plan was simple: he shows us how to weld, and I keep a fresh beer in his hand. It worked out well for everyone. While he got the welder set up, he taught us with welding scraps from the old torn-out floor. This gave us opportunity to work on pieces that didn't matter, but were the right thickness and material. We ran the temp / voltage as high as it would go (D) and the feed set pretty fast too (just below 9). Because if the thickness of the rails, the high-voltage setting makes sense. For other work, like repairing the rear bulkhead the previous owner cut a big hole in, I'll need to bring the temp way down. Before we were done for the evening, the passenger pan was in, and 3 of us learned how to MIG weld, including my wife's sister. Very fun.

During the actual weld-in, we had setbacks, of course, like some burn-through of the pan when we novices tried to run a bead, or small fires from grease or paint catching fire from the welding. Not to worry, though, they were small enough to blow out. Still, the decision to weld on the driveway rather than the standard low-ceiling garage turned out to be a good idea. We tested a few of the welds just for curiosity sake by banging on them with a hammer and trying to separate the panel with pressure from below. No dice.

I've gone back and forth about grinding down the plug-weld humps. I know the floor is going to be covered with sound reducer, a carpet pad and then carpeting, so no one would ever really see them. At this point, though, I'm trying to get the car on the road before the weather turns, so maybe I'll grind the humps down under a canopy once the weather changes this fall. Or I may just leave them alone, and focus energy on value-adding efforts, which grinding down weld-humps in an area no one will ever see... frankly isn't.

That's it for today. My final steps are seam-sealing the floor edges, and getting some paint or undercoating on the steel pans. That work may not be interesting enough to warrant a post. After that's done, I am going to focus on getting the fuel system and master cylinders re-installed. Expect posts on those efforts soon. As always, thanks for following along.

MGB - floor pans (Part 1)

Today's post is the first of a series dedicated to the removal and replacement of the floor pans in my MGB. This process would be the same for any car whose floors are not a critical part of the structure. I believe most cars fit that description, but I'm sure there are some unibody cars out there which have particular demands on the floors requiring a little more expertise. On that note, let's be very clear: I have zero prior welding experience. Nada. Zip. I've tried to play with a stick welder and was unable to strike a spark without getting the stick stuck to the target material. After a few hours of that frustration, I gave up, put the welder under my workbench and moved on. Until now.

The Patient

right side floor - before

I have posted quite a bit about the journey with this little British car since I acquired it late last Summer. After a spirited drive home with no seatbelts, no brake lights and little understanding of how it operated, I've made many improvements:

• brakes (link)
• fuse box (link)
• master cylinder / pedal box removal (link)
• engine mounts (link)
• rebuilt the front suspension (link 1, 2, 3, 4) including front wheel bearings, etc
• new seat belts, rear suspension rebound straps, fixed the brake lights (no links)

While working on the front suspension, I had a volunteer in K2 ask if he could help out. I wasn't in a spot where unskilled hands were really a help, so I asked him to start removing the interior. The carpets smelled bad and were pretty worn, so I'd intended on at least getting the smelly stuff out and putting in a temporary solution until I had the cash to do the interior well. That is where this story begins.

Discoveries

left side floor - before

With a 1/2" spanner and a small ratchet, K2 was able to remove the 4 bolts which hold in the passenger seat and pop them into a ziplock baggie. We pulled the seat, and set it on the floor. I left K2 to the carpet and I returned to the suspension. K2 did a great job pulling the carpet free from the floor, and the transmission tunnel. The floor looked fair, with surface rust, but half of it was covered by the original sound deadener. We split the task of hammering that out with a chisel so we could evaluate what lay beneath. There were some rusty spots as you can see in the upper picture, but only pin-holes through.
Prognosis: fair, but will require some work to have them sealed up. Replacement suggested.

With the limited space in the garage, K2 had to perform some gymnastics to get after the bolts holding the driver seat in, but once removed, he made quick work of the carpet and we cleared the sound deadener much faster as well. Unfortunately, as "okay-ish" as the passenger floor was, the driver floor was pretty bad. There were multiple small holes and the sound deadener came out so easily because of the heavy rust underneath it. Upon further examination, the floor around one of the nuts for the seat had cracks in it.
Prognosis: This floor was toast. Replacement required.

Decision made: we'll replace both pans, one at a time, and hopefully have the MG road-able before the next rainy season starts.

Pans

aftermarket pan

When it comes to the floor, there are OEM and aftermarket floor pans. The OEM cost about twice as much, but they have all of the little things that make them easier to work with. They have the nuts for the seat-bolts already installed, and the reinforcements to the floor around them. There are various little threaded studs on the underside that are on the OEM pans. Last, of course, they are heavy British steel. The aftermarket pans do not have most of the fasteners attached, are made with thinner (not British) steel and they reportedly have an extra lip around the edge that needs to be cut off. Based on the pictures, it looks like the aftermarket pans also lack the drains. neat. I chose the OEM pans, and ordered a set through my local MG specialty shop: British Auto Works in North Plains.

Weld or Glue

OEM pan

There is a whole religious war about using a structural glue to attach floors, or other "non-structural" panels. The glue argument goes "modern cars are glued together, and the new glues are far better than anything they had back then so the manufacturers would have used them if they'd had them". Sounds reasonable. The weld counter-argument goes "modern cars are CAD designed with things like cost of materials and time/effort factored into the engineering so the glue is part of the engineering work, the crash testing, etc so gluing anything that isn't purely cosmetic on a non-glue car is a bad idea". This also sounds reasonable. I decided that I'd err on the side of caution and learn how to MIG weld on these floors. I have always wanted to learn how and while floors may not be structural, my seat is bolted to it, so it feels a little more important than, say, a rear spoiler. With this in mind, I reached out to my wife's sister's boyfriend to borrow a welder, and some welding instruction. But, before we get too far down that path, we need to remove the old. We'll get to that next time.

That's it for today's appetizer of a post. More to come on this topic for sure. Thanks for following along.

MGB - Front Suspension Refresh (Part 4)

This post finishes up the front end rebuild I started in Parts 1 (See MGB - Front Suspension Refresh Part 1), 2 (See MGB - Front Suspension Refresh Part 2) and 3 (See MGB - Front Suspension Refresh Part 3). At this point, the front beam is back in the car. The front shocks (and upper control arms) and lower control arms are installed with the spring pans. Today we will get the springs in, the swivels mounted and the front sway bar attached to the lower arms. By the end, the car could go back on the ground. The how-to for the springs I lightly touch on because it is pretty well documented around the internet. Not so much with the sway bar, so that's a little long.

Spring Thing
Back in Part 1, I described the concerns about how the springs were under load when the lower control arm was to be removed and that some level of care was needed to prevent it from launching across the garage. That concern returns as we approach the install. I followed the exact same routine: zip-tie the upper end of the spring to the top of the beam. Getting the zip-ties in the right spot may take a few tries with the jack (during the Jack Be Nimble step), but for now, just get the spring all the way up in the beam pocket and zip tie them so they are mostly in the right spot. Once the springs are suspended from the beam, we move on to the swivels. I did one side at a time, but I don't think there's a compelling reason to other than I confuse easily.

Swivels, bottom mount
The swivels are really nicely balanced lumps of steel, when they are mounted to the suspension. When you are holding them in your hands, or trying to attach them, however, they feel unwieldy. So, to protect yourself from, uh, yourself, put something soft under the end of the beam to catch the swivel when it inevitably topples over. It will topple. Since I had a bunch of things shipped, I took a larger flat box and filled it with the crumpled newspaper and air-filled bags that arrived with the parts. I highly recommend it. The alternative is a damaged swivel. Anyway, take the swivel for the side you're working on (caliper is on the rear), and fit the lower mount into the lower control arm. Thread the bolt from the kit from the front to the rear, minding the order of the washers (nut - washer - rear arm/bushing - swivel - front arm/bushing - washer - bolt head). Once you thread the castle nut on, you may feel driven to crank it on tight. Don't do that yet. Get is on pretty well, though; finger tight.

Jack Be Nimble
With the swivel attached at the bottom, it will want to fall over, especially when you start lifting the lower control arm with your jack. To prevent that, I looped a stretch of bailing wire around the top of the swivel and then around the shock absorber. This loosely held it upright, but didn't restrict movement. Now the fun part begins. Lift the lower control arm under the spring and set the inner edge of the spring inside the spring cup. Now, set your jack as we did in Part 1, on the outer edge of the underside of the spring cup. Slowly start raising the jack. I did it in spurts and then wiggled or rubber-mallet'd the bottom of the spring so it would shift in the spring cup. My thinking was that the cup was rotating 90* so the spring would be under weird tension as is was set into place, putting more pressure on the inner edge than the outer edge of the spring. I don't think it did much other than create more danger of the spring flying out, so consider that optional.

As I got closer to fully-installed, I found that the spring tension was greater than the weight of the car. I mean that the car started lifting off the jackstand before the top of the swivel was within an inch of the holes lining up. If you have a friend, not even a very heavy friend, have him or her sit on the wing over the wheel well. I was flying solo, so I stacked tires on the wing instead. Yes, that actually worked.

Swivels, top mount
As I alluded to in Jack Be Nimble, most of the top mount work is getting the jack positioned right, and raising the swivel while keeping the car solid on the stands. Once the holes in the upper control arm / shock absorber align with the hole in the top of the swivel, it's easy. I found that getting the top of the swivel to sit in the arms wasn't simple though. I needed to loosen the bolts that hold the top arms together a little bit so the swivel top could fit. You may need to do that same, just don't forget to torque them back down when you're firming up all of your fasteners.

Now do that again for the other side. I found that the first one took at least twice as long as the second side. Ironically, I had more spring slippage on the second side, but that didn't slow me down as much of the fear of that happening on the first side slowed me. Interesting.

Anti-Sway Bar
With the rest of the suspension put together, all that's left is the front (anti-) sway bar. In my searches around the internet, all of the articles I found about replacing the sway bar had the classic "install is the reverse". That is not helpful, so I'm documenting what I did that worked. If you're using your original bar, clean it up and paint where it's been chipped when you're doing your other parts. It is so much nicer, and the bushings go on much easier. We start with those bushings. The graphite-poly bushings are a solid trapezoid, so you will need to cut along the seam so it will wrap around the arm. I tried sliding it on from either end, including removing an arm-end, but that doesn't work. You have to cut it parallel to the path the arm would take through it.

Get the bushing onto the bar. This can be hard, but with some window cleaner (or plain water) as a lubricant, and a little force, it pops on. Use the little locks on the bar as a guide for where they should be located (just to the outside of the lock/clamp). Now test fit the bar with the new brackets. For the MG, there are 2 small black pieces of steel that hold an air deflector that need to fit between the bracket and the frame. Just test fit that it will roughly fit and that the bar is pointing the right way (ends pointing rearward).

With the brackets now removed you're ready to start the install for real. Hold the bar in the rough spot where it was during the test fit and wiggle one end of the bar into the lower control arm. Since nothing is preventing complete movement, this should be relatively easy. If the sway bar end is not making it through the hole no matter what you do, you could be experiencing a manufacturing defect in the arm. I had this happen: the rearward hole was too small for the sway rm end to pass through. I had to widen it with a drill.

Once the first one is through both holes so a bunch of threading can be seen/felt on the rear side of the control arm, switch to the other side. You may need to work kind of hard to get the second side in. I did. Lots of pulling and pushing before the bolt passed through both holes. Set the ends all the way in with a couple of whacks with a hammer. Place on the lack-washer and the 3/4" nut, but don't tighten it all the way down. Now shift to the brackets, the metal thing, and the bushings. Thread in the 2 pairs of 1/2" bolts, but again, don't tighten. Now, push/pull on the bar left and right to makes sure it is centered and there isn't any torque holding it out of center. Now, tighten the bolts and nuts down. Again, I recommend new fasteners.

Now, we can lower the car. I set the jack under the rear edge of the front beam, lift the car just enough to get the stands out and set the car down. After so many months of the front being in the air, it really looks kind of weird. Really low. For fun, I jumped up and down on the front bumper. Where there used to be considerable bouncing both on the initial jump, but in aftershocks as well... the MG barely responded to my jump and didn't bounce. It just returned to it's ride height. So tight. Once I get back on the road, it is going to hold the road like a brand new (or better) MGB.

That's it for today. This has been an incredible marathon, but feeling the difference bouncing on the front bumper tells what it will be worth. The front end should be in solid operating shape for another 40 years. Thanks, as always, for following along. I will get the festival review, the bus improvements, another road story, etc. posted as I can get to finishing the stories.