4x4 Labs Rear Bumper System for My 70 Series (2 Viewers)

[wardharris]

When I got my BJ 73, one of the key shortcomings was the OEM rear bumper and redneck trailer hitch.

As the former owner of an expedition built 60 Series, I had added a 4x4 Labs to my wagon and loved it. That was my ideal solution but Luke Porter at 4x4 Labs did not list a model for the 70 Series.

No disrespect to other vendors here, but the design, fit, finish and functionality of the 4x4 Labs offering were preferred. The Labs product replaces the rear frame crossmember which allows a tighter and more integrated fitment, pulling the bumper closer to the body. They also look really cool.

After a bit of dither, I discovered that Luke's first bumper build was for @dieselbigot for his Canadian BJ 70. Unfortunately, it was so long ago that the specs were not retained so a duplicate could not be produced.

After a conversation, Luke offered to build one for my 73 if he could get hands on the truck for a couple days to measure, mock up, prototype and get the build into his CAD system.

Two years later, following the build-up of my 73 with a new drivetrain, it was time for a road trip to Grass Valley, CA. Luke and Ryan pulled the rear cross member of my 73 and got to work designing and mocking up the new bumper. I will return in a few weeks for final install and keep you posted on progress and results.

Luke plans to offer the 70 Series bumper in kit and finished form.

BEFORE

AFTER

 

[wardharris]

For those with concerns about the amber turn signals blocked by the spindle housings/swing arms, the European 70 Series tail light lenses on my rig (and others) provide location of brake and turn lights above the blocked position. The bottom third of the left lens is "dead" without a bulb and I plan to add LED reverse lights to the bumper and retire the back-up light on the right side.

 

[wardharris]

WHAT A CAD
The guys at 4x4 Labs have a pretty sophisticated operation. After 15 years Luke and the crew have figured out how to design and produce a range of metal products that can also be modified, enhanced and delivered to end users efficiently.

In the case of my 73, they started by assessing the "patient" and conducted an extensive discussion of what I wanted to accomplish. They then proceeded to carefully remove the rear crossmember as noted above. Some folks get a little queasy at this point, but there are a total of eight connections between the frame rails (four frame tubes, one rear crossmember, the engine, the transmission mount and the body, which is secured with ten body mount bolts) which keep things where they belong. The rear mount is not permanently removed, but is replaced by the 4x4 Labs bumper system.

My frame is shown at left below after a robust effort by the Torfab crew - both wire wheeling and painting, but also cleaning up the mangled rear cross member - which was subsequently removed by Luke and Ryan.

They didn't just attack the truck with a plasma cutter, but carefully assessed the OEM metal and went at it with angle cutter, sawzall and grinder. The rear of the frame rail has lots of stuff going on - body mount bracket, crossmember, corner brace, etc.

Here is a view after the first several cuts:

Ryan working the grinder:

And the end result (sniff, whimper):

 

[wardharris]

With the back end exposed, it was time to make a paper template of the rear attachment horn and then tracing of the hole positions - using a mounting horn for an FJ 55, Luke determined how close to that existing item the 70 Series would be:

With some measurements and that tracing, he managed to get the 70 Series horn into the CAD system and he was then able to use the plasma table to zap out the first prototype mounting bracket:

And here's the finished prototype in place on the 73 - this was a little tight so he took a Mulligan /do-over to increase the clearance from the rear doors:

Here is a shot of the same bit as installed on a Piggy:

 

[wardharris]

QUICK & CLEAN

I don't know anything about CAD design and production systems, except Luke can quickly crank out different versions of new parts in flat steel, then bend, finish and test fit them on the truck in no time at all:

Documenting:

Cutting:

Finishing:

And fitting the final product - in this case carrying a bumper shell borrowed from a 60 Series parts bin:

 

[wardharris]

WHERE'S THIS GOING?

Good question - the end result will look something like this, except a little narrower and with a nice coat of powder

Here's the mock-up fitting, with the aforementioned 60 Series bumper shell. This piece is too wide for my little 73 by about 1.5" and the shackle horn holes need to be moved in line with the frame rails. In another change from the 60/80/100 Series bumpers, the hitch receiver retention pin will likely live on the outside of the bumper, rather than behind. The bumper sits so close to the crosspiece, it is not likely possible to internalize access.

There are plenty of options for accessorization of the dual swing arms as shown below. I am going with a spare carrier on the driver's (left) side of the truck with a low-mount 3-can gas carrier on the passenger (right) side. Luke says the 3-can is also a popular mounting point for a Yeti 35 cooler. The can rack also has a license plate mounting plate and that's where mine will live.

 

[ForealBoreal]

Paying very close attention. Keen to see how this works out as I am very very interested......

 

[wardharris]

Will keep y'all posted. I am interested as well.

PS - Staff hydration is always important.....

 

[Diesel Cruiserman]

I like the clean lines...

 

[wardharris]

I like the clean lines...

High praise from a guy who knows steel.....

 

[wardharris]

MORE CAD

Here is a picture of the 4x4 Labs side plate in 3D. This component fills several roles - it is the outer frame for mounting the bumper shell, it protects the lower rear quarter panel of the vehicle, it attaches the bumper system to the frame at the body mount bolt and it provides a secure receiver for a Hi Lift jack.

FINAL MOCK-UP

There is a square tube cross-piece that goes between the added frame horns - bolted between the two. This photo shows Luke and Ryan bolting it in for the first time.

Here's another snap showing it in place. The internal cross-bube is also the internal connection point for the hitch receiver.

Here is the cross piece and hitch receiver in place on a different rig, fully installed.

 

[orangefj45]

Awesome!!

Really looking forward to seeing the completed product.

I've got one of Luke's bumpers on my 100 and have installed them on customers vehicles.

Top notch!!!!

Georg @ Valley Hybrids

 

[deepseacruiser]

I want!

 

[ForealBoreal]

Updates?

 

[wardharris]

Updates?

Thanks for the reminder, sir.

Taking a road trip to Grass Valley for final fitting next week. Will go to PC and final install soon after, then report back.

 

[ForealBoreal]

Dammit I want one.

 

[wardharris]

Rest assured, you are not alone. Many eyeballs on this product development effort.

Although i am not affiliated with 4x4 Labs, I am comfortable stating that they will have these for sale within months, if not weeks.

As noted above, there are lots of good options out there, but as a repeat owner, Luke's junk is what I want. I thought long and hard about rear access and the benefits of swing arms tied to the rear doors like Cruisin' Offroad's bumper. I love Jason's products and have his sliders on the 73, but I decided to go old school and keep the weight all on the bumper with no connection to the doors. Just personal preference.

 

[Gun Runner 5]

@wardharris ....... "but I decided to go old school"

 

[wardharris]

@wardharris ....... "but I decided to go old school"

You know I don't like newfangled stuff.

 

[Gun Runner 5]

You know I don't like newfangled stuff.

The only thing about that 73 Series that isn't "newfangled" is the owner.