4X4Labs Rear Bumper Build

[TrillyPop]

If you don't mind, I'd like to see a photo!

Absolutely. Here you go. If it does every start to fall off, it's really easy to replace as I got a pretty big sheet of ABS for free at a local plastic supply place. It's the best solution I could come up with.

 

[changingground]

I saw an 80 series 4X4 Labs bumper that had something that I don’t know how to explain. It had a concaved dome piece under where the end of the arms meet. The tabs on the bottom of the arms that push against the stop slid over the concave piece and it helped hold the arms in place. I wish I had a picture. Would like to try the same with mine to decrease the rattle.

Can you post a picture of what you’re referencing? I’d like to see it.

 

[VagabondJesse]

Well, it's been pretty slow going. Mostly due to the fact that the garage is right under my 2-year-old's bedroom. I can't run a grinder in there while he's sleeping, and I've... uh... needed to do a lot of grinding.

I welded the towing crossmember, guessets, receiver tube, and recovery points and stuck the assembly back on the truck so I could fit the side tubes and "trim pieces" as I'll call them. Started by fitting the end trim piece with the tabs and rounded part, making sure they were square to the top surface of the bumper and square to the front edge. Tacked in place, then tried fitting the other trim piece- the bent one with four sides shown below. I was hoping to have the bent edge fit against the bumper side wing, and have the other edge sit along the edge of the trim piece with tabs. The geometry just wasn't working for me though, and the best I could do is what you see below (shown after I tacked the side tubes).

I figure I'll cut that end trim piece so it doesn't stick out, after I get a little further along. I was left with a little gap between the tube and the rear trim piece, but not so much I couldn't fill it at welding time.

Cutting the side tubes was pretty straightforward, but I failed to measure/mark twice before I cut once. Ended up welding the tube back together and cutting it a second time. No real tips at this point other than make sure you leave a bit of space between the tube and the truck. Whether the tubes stick out for added protection or sit more flush for a cleaner look is a matter of personal taste, as far as I can tell.

At this point I decided to start assembly of the tire carrier. I hammered the sleeves into the swing arms, welded, and ground flush. Nothing exciting there. Same with the swing arm end caps. The wording for the actual tire carrier assembly was a bit confusing for me, but pictures seemed to clear everything up. There are two pieces- I'll call them the upright and the clover, with the upright being the part attached to the swingarm and the clover what the tire bolts to.

Tack the vertical piece of the upright to the piece which bolts to the swingarm. Make sure the upright is square. Then tack the gussets in place. I did my best to make the gussets use the full width of both pieces. I don't have any pictures of this, but its the same you can see in the official instructions or on the other threads. Positioning the mounting assembly on top of the vertical piece was a bit tedious. I ended up using a c-clamp to affix the side pieces to the upright for positioning. I also used a ~1/16" spacer between the clover tube and the top plate as suggested. It doesn't seem the front/rear positioning of these side plates relative to the vertical tube really matter. Just make it look good.

The clover assembly was simple enough I didn't take any pictures. Just mark the center of the clover and position the tube on it, keeping an eye on your rotational alignment so the "star" is pointing the way you want it when you're done.

That's about as far as I've gotten. Lot of welding, grinding, and welding again not shown. But my beads are starting to look a heck of a lot better than they did at first. I took the day off yesterday and bolted the unfinished bumper shell to the truck and took it to the trails. Rode it pretty hard and got warm and fuzzy every time I came off an obstacle that previously would have resulted in my rear end dragging. None of that now!

 

[VagabondJesse]

I'm 99% done with the rear. Rather than document every little weld I've done, I'll just list a couple of pain points and tips. First, the swing arm stop needs to be mounted toward the rear edge of the bumper, with the corresponding stops on the swing arms on the trailing edge. Originally I had the stop like in the photo below, and you can see the damage on the tailgate when I carelessly lowered it the first time without thinking to check clearance. The good news is that so far the latch doesn't rattle or clunk at all. If that changes I'll add in some plastic to keep things tight.

Originally I had planned to put the included antenna mount on the rear of the tire carrier, and attach the high-lift mount to the ladder. I was having a heck of a time getting the geometry right on the high-lift mount, so decided just to attach it to the rear of the tire carrier. The instructions say that's an option, after all. If I was running some super skinny tires, this might not be a problem. However, the plane of the jack passes pretty much through the center of my spare (285/75/16) as can be seen below. I'm going to get a short section of square tube and extend and angle the back, hopefully solving the problem. I think I'll put one antenna mount on the spindle and one on the roof rack for times when I need all the range I can get.

So all that's left is to fix the high-lift, attach antenna mounts and license plate bracket, and take it for powder coating! Overall I'm pretty happy with how things turned out. If it weren't for my sloppy welding at the start, I think this could have been tackled in a long weekend, either with two people for installing/removing the bumper, or with a hydraulic table.

The almost-final result:

Now on to the front so I can make a single trip to the powder coater...

 

[atnolan94]

Dude i did the exact same thing with my tailgate and had the exact same hi lift issue. Mine is welded on there but it can't be used.

 

[VagabondJesse]

Dude i did the exact same thing with my tailgate and had the exact same hi lift issue. Mine is welded on there but it can't be used.

Well, that makes me feel a bit better! I'm glad I caught it before taking it for powder. Still time to fix it. Do you just throw your high lift inside?

 

[atnolan94]

Well, that makes me feel a bit better! I'm glad I caught it before taking it for powder. Still time to fix it. Do you just throw your high lift inside?

I actually ended up forgetting to do anything about it and didn't take a hi lift on my last trip. May just figure out a roof rack setup or swap to a bottle jack. Putting it inside seems a little too dangerous. That's one heavy javelin.

 

[Tanner H]

I ended up not using the high lift mount provided. I'm not a big fan of hi-lifts for several reasons, but i was also able to slide the spare tire much closer to the tailgate without fear of the mount bouncing into the tailgate on rougher trails. i think closer to the truck puts less strain on the tire holder. maybe im overthinking it.

i just carry around the oem bottle jack and one of land cruiser phil's adapters.

 

[atnolan94]

I ended up not using the high lift mount provided. I'm not a big fan of hi-lifts for several reasons, but i was also able to slide the spare tire much closer to the tailgate without fear of the mount bouncing into the tailgate on rougher trails. i think closer to the truck puts less strain on the tire holder. maybe im overthinking it.

i just carry around the oem bottle jack and one of land cruiser phil's adapters.

View attachment 2762867

Yeah now that you say that, I slid the tire carrier arm all the way back as far as I could. It sits tight to the body but not tight enough that it would touch. Not that this affects your ability to get the hi lift on it, because it still doesn't work.

 

[ceylonfj40nut]

When I was 18 I had a job installing loading dock equipment where I did a lot of stick welding. I never really learned how to weld properly though. It was a situation where the welder was already set to the current that we used, we only used one type of rod (didn't know what kind at the time), and pretty much everything was 3/16" mild steel. I welded a few different types of joints in a few different positions and directions which required different techniques, but my skills were rather limited.

I didn't realize that until I started this bumper. It's been a long time since I was 18. The little skill I developed is long gone, and I learned mighty quickly that different electrodes behave very differently. I now believe everything I did when I was a kid was probably with 6013, and I've used 6011, 7018, and 6013 for this project. All of my 7018 beads looked like crap, and all but the very last 6011 bead was just as bad. When I switched to 6013 everything magically turned out great! Luckily I did all of the hidden welds with the 6011 and 7018, and most of the visible welds are with 6013. I'll be grinding all the visible ones for aesthetic reasons, and nearly all of them have some awful looking welds on the other side of the joint, so I don't have concerns about the structural integrity. This is a very stout bumper.

Oh, and I had it in my head that I would have the patience to TIG weld this whole bumper, since I've had a fair amount of practice at that in the past couple of years. Granted, most of that was on stainless, and on rather small stuff around my home brewery. I did about 6 inches of TIG before I realized that it would take me weeks longer than I had planned. That was when I grabbed some stick electrodes and decided to refresh my muscle memory. Anyways, back to the bumper at hand.

With the basic shell in place, I made sure all of the mounting bolts were tight and then tacked everything.

View attachment 2729336

I thought the next step was to take the bumper off and then finish weld everything. It turned out the next step was to drive to Harbor Freight and pick up a hydraulic table so that I'd be able to move forward without another set of hands. The cruiser is the only vehicle I had big enough to bring the hydraulic table home, so I drove there with the tacked-together bumper on. Luckily it's less than 2 miles down the road. Back at home I welded all the joints I could reach. If you know what you're doing, the gap at the corner of the bumper shouldn't be too hard to fill. If you're me this past weekend, it's a bit of a pain.

Then grab a beer and wait for the bumper to cool before installing it back on the vehicle to make sure it all fits, welds aren't getting in the way, and nothing deformed so much as to make reinstallation difficult or impossible. Luckily I didn't have any problems here. Remove the bumper again and we'll add the receiver, towing crossmember, receiver gussets, and recovery points. The crossmember will likely need to be cut to length. Do this, then tack in place on the top edge, somewhere that will not interfere with sliding the recovery points flush to the crossmember. You can tack the recovery points in place next. The bumper is upside-down in this photo:
View attachment 2729348

Then you can slide the receiver tube in place. It will sit flush up to the towing crossmember, but because it's a bigger tube than the crossmember, you won't be welding all four sides of it because the bottom face will sit about 1/4" below the crossmember. The gussets can be tacked in place at this point. I welded mine flush with the edge of the crossmember so they're as low as possible. My thought was that will make it easier to attach safety chains when towing.
View attachment 2729350

Then it's a matter of finish welding everything to this point. And in my case grinding. If you're a better welder you can probably just chip off slag and move on to the swing-out spindles. I'm halfway through grinding and cleaning up, so I'll add more once I move further.

 

[Golden Dragon]

Stress fracture. Just weld again?

 

[kevgentile]

Stress fracture. Just weld again?

View attachment 3623771

The areas along the perimeter of a weld are always the weakest. No room to plate it under the swing out.
Drill out the crack at the ends, channel out the crack for good bead penetration, clean, and weld. Might crack again down the road but it'll hold for a while.

 

[hoser]

Was the spindle welded through the bottom as well or just that top plate?