Father & Son Build - Rear Suspension Subframe

Way back in April, Nathan and Sam had finished a rush of assembling and getting Nate's Baja "show" ready. The car was rushed together enough to drive on its own, and it did, into and out of a show. Despite being a driving car at that point, the car didn't have any rear shock absorbers. Aftermarket 3x3 trailing arms don't have shock mounts, and the design of the arm doesn't allow the stock upper mount to be used. Since Sam & Nate don't want to cut into the rear fender wells to run an off road style shock absorber, they will have to come up with another way. This rear subframe should help and if nothing else, it will help support the rear of the chassis, possibly offer a mounting point for an air conditioning condensor, and will give the "show cage" a place to tie in to the chassis at the rear of the car.

Video Transcript

Nathan, I am your father.

All right, guys, we're back at it again. Obviously, we've got our body in place temporarily. Just looking up yesterday, we played around with it and took some measurements. Now, we're just taking out the cold heater ducts because we're not going to be using heater boxes. We're taking out these guys—this one's actually in good shape, but the other one, not so much. We'll set this aside for now.

All right, you can drop that down. It just so happens to sit ever so nicely right there. From here, we're going to go from this corner down to the frame horn, and then from that point, up forward into our torsion housing to give this a nice rear subframe, for lack of a better term. To do this, we're probably going to have to pull the transmission out so we can weld some plates on. For now, we'll at least get this bar measured and cut, and possibly test fit.

I've got some straps so I can weld over the top of that. Yeah, just a whole bunch of cutting, fabbing, notching, grinding, and welding to get this bar mounted in place here and then supported there. Sound good, Nathan?

Yeah, buddy.

All right, inch-and-a-half, 0.095 tubing—nothing fancy. We're not building a race car, so it’s not DOM or chromoly or anything like that. The measuring tape's over there. We need to go from here to there, which means we also might be using the tubing bender today. Maybe?

Yes, I think so.

It’s a good thing they have these little notches for the heaters because then we can just run the tube right straight down into them. Two pieces of tubing at 17 inches, and then we’ll start worrying about that.

We did some temporary testing using our old original shock as a mockup and verifying it with some measurements from work. A stock Bilstein IRS shock is 16 1/4 inches extended and about 11 inches collapsed. That’s roughly equivalent to this. This one will actually get a little bit shorter, but it is what it is.

If we were to go to full droop and put the shock somewhere roughly here and mount it here, we’d end up getting about 10 inches of suspension travel in the rear. Again, not cutting into the body. We’re limited by how short of a shock we can get, and at full up travel, the shock would be up into the fender. We don’t want to do that.

To go from there to there, it might just be coming up over the top or something. We’ll figure it out once we get all this in place. This is the easiest part because it’s just boom and boom.

For now, you want to yank that transmission out?

Sure.

That tube out of the way.

Don’t want to use a big dog.

You get it?

Yep.

To give some reinforcement to these frame horns, I’m just going to take a piece of flat stock and weld it and beat it over the top of that. That’ll give it some meat because this is literally just a piece of sheet metal—not a whole lot of strength there. Even though it does have a piece of metal on the inside, it’ll also support the transmission.

From this tube to this tube and this tube, we’ll actually have a plate on the bottom side here. Most likely, we’re going to tie the inside roll cage into this frame here.

First, we’ve got to grind our core seal off and then I’ll start buzzing this guy in place. I’ll just keep shaping it over the top of that tube.

Welding that on now. It doesn’t even look like it’s ground down, huh?

Yes, welder helmet. Well, at least now you can MIG in fancy new gloves.

You mean ones that you won’t burn yourself on because you have PPE in?

Hopefully not.

I just got a new welder. I’m trying to get used to it. I’m not a welder—I just know how to weld, kind of.

That will do.

All right, Nate, are you going to play all day or what?

I might just weld this off back there and then off this tube here.

Oh, I see what you did.

Would’ve seen it a lot closer if you’d been over here paying attention instead of playing around.

What?

Yeah, all right. Well, anyway, this tube’s in—17 inches should be more than long enough.

That tube will go from there to there.

Honestly, we don’t really need a whole lot of notch on that guy.

Where’s my measuring tape?

That worked really well. Nice notch. Now I’ve got to fit out our angle for this guy. That notch is there.

Let’s get my angle finder. It’s 43, but I want to come in a little bit more, so I’m going to set it at 45. We’ll see what she does. Identical.

I like that. That guy’s in my way. No longer in my way.

Now I’ve got to make sure the bar is from the torsion housing, inch and 3/4 and two inches, inch and 7/8. All right, that’s good.

Twenty-one, just that. Got 20 and 15/16, 10 and 1/8 to the shock hole, 10 and 1/8 to the shock hole. We’re just kind of like right in that middle ground.

That’s definitely going to have to be solid when we do the forward bars, but that’s a start. I guess I’ll get these things better tacked in, but still just tacked in until I get these forward bars done. What I want to do is go from this tube to here. This angle it’s currently sitting at is about 2 degrees.

To go from the torsion housing to there should clear the body. That angle is 47 degrees, so another 45-degree bend. This was a 45-degree notch, and this is going to be a 45-degree bend on the Rogue Fab bender. My bender has a 6-inch die and a 6-inch offset. I don’t have any scrap pieces to check with, but I’m guessing about 9 inches is where I want the bend to start, and then overall about 25 inches long when finished. If I’m starting there and dragging the tube that way, I’m going to give myself 10 inches before the bend. I need 4 inches of tubing sticking out of my die. We’ll go five, just because.

I think that worked out kind of well, although my camera’s probably dropped. I think that worked out well. What’s the diameter on this housing? I think about 3 inches, 2 and 3/4. Start cutting it and go from there. Cut a little bit more for there.

I’d say that could have been a little bit longer, but it’s a good proof of concept. Should’ve made it just a snug bit longer, but I can do that. I have enough pipe. Yeah, a little bit short. You can always cut more off, but it’s not quite as easy to add more. Proof of concept there, and honestly, it’s not that far off, especially if I were to come out to this joint so I can come in over the top of that tube right there.

If I do that, that needs to be notched a little bit more. There we go. That will do. I can deal with that. If I get out here, and I want to get straight into the body, the body’s kind of in the way. So if I just kick it in just a touch, I’m really happy with the way this notch is and this fitment there.

Ideally, I’d like to have this pipe even with this body right there. That gets me an idea of where I want to be. Bring you guys in so you can see. All right, so I want this tube to be pretty much flush there and then drop down to here. Obviously, I’ve got a big gap here because I wasn’t planning on this initially, but having bent it and gotten it in shape, I think that’s what I want to do.

There’s just too much body in the way right here to be able to take this thing straight. So doing that little kick the way I had it a minute ago will get me in line across the bottom here, get that tube fit nicely there, and out level there. I need to make a new one of these tubes, but at least I’ve got a better game plan now that I’ve got this piece done.

Luckily, that one’s not long enough, but I have another 10 feet over there. So I’ll measure this, make it a little bit longer, and start off on another piece. Finally, all done. Almost all done.

What’s this other one for? That was my test piece.

Cut out our hole again. That’s not promising. Sit down. It’s not good. I’m done. Well, I’m tired. We’ve got plans for dinner, so I’m going to call it a day. We’ll be back at this again tomorrow. See you.

New hole saw, new day, old clothes. I’m in the garage, I don’t care. I got this tube marked here. This is my vertical, and my horizontal.

It’s got the degree on here. Yeah, not straight. This is going to come in and dog-leg that way.

Oh yeah, almost there, almost there. Keep going. Boom, a little bit more. Yeah, good. All right, make sure that’s right, buddy.

I’d say we’re doing pretty darn good, right in that neighborhood right there. Yep, that’s much better. It looks so cool, huh? Just like looking from here. See? Yeah, I think that works pretty darn well.

Perfect. That will do the job so much better. Get some of this stuff out of my way down here so I can actually come in here and get some proper tacks on this. That looks really awesome.

Then we’re going to have the shock mounts. The next step is going to be seeing if I have some stuff we can use for shock mounts. Once I have the shock mount, I’ll know what we need to build to get up to it from here. Something a lot thicker than this, I’m guessing. Do I want to pull this transmission out of the way? Probably should. Yeah, let’s do that. Jack it up a little and see if I can get to that mount.

Also, we’re going to have to spot all those little holes in too. Yep, maybe I can do some welding. Wow, look at that, huh? It looks so good.

All right, that’s about as much as I can do for today. I guess I could go through and weld the rest of these tabs on these control arms. The new welder I got, this guy over here—the Firstess VP 200 YesWelder—anyway, this machine can do TIG, MIG, stick, pulse, and a whole bunch of different stuff. I don’t have all the stuff to do TIG yet, but I want to get that soon.

Hi, Nathan! Here’s the camera over there. He was inside. He didn’t stay out for this part.

Until we pull the body off, I can’t weld much more. I do have enough welds to the point where we can put in shocks now. So I’ve got to get shocks and threaded shock bosses. Then I can worry about getting the upper shock mount located and start connecting it to our subframe.

That’s it for about all the work we can do today. We’re kind of at a standstill until I get shocks and upper threaded mounts.

On that note, life’s full of good people. If you can’t find one, be one. Later, guys! Solid as a rock—like a Chevy commercial.

Nathan, I am your father. Maybe we’ll leave that in the video because we’re still recording. Maybe we’ll do that as an intro. Yeah, all righty. Call it a day.