Building the perfect 90

[erover82]

I like the open feel of trucks without rear bulkheads, but I also like having separation of cargo space and a surface to mount tools, so I split the difference and went with a bulkhead reduction bar. To this end I built a custom bulkhead to match the bar's geometry and utilized slightly thicker aluminum to better resist the many dents they typically accumulate. The most difficult part was getting ~1mm accuracy in all dimensions to ensure all mating parts would align properly.

Test fitting the bar and a few panels together with clamps.

More test fitting. Spent hours aligning and tweaking the panels before everything measured as square as possible.

Finally drilling the rivet holes with everything clamped precisely.

Drilled the rear panels with a NAS pattern, my favorite light layout. The capping began as a standard galvanized piece which I welded the upper lamp hole closed and epoxy coated.

Then tore the whole tub apart (again) so it could be reassembled by bonding.

Beginning reassembly with a good little helper.

Many rivets and several tubes of bonding adhesive later. The horizonal bulkhead stiffener can be seen here too. This replicates the factory stiffener but stronger and assists the bulkhead bar in maintaining structural integrity since I was able to integrate the riveting of both together.

Installing wheel arch stiffeners.

Gave the capping mating surfaces a thick brushed-on coat of epoxy to prevent corrosion.

 

[Ansley Rover]

We've never met other than in this forum, but it's crazy to see how much your kids have grown from the first page of this post, when we all started following your thread, to now.

 

[Z.G]

We've never met other than in this forum, but it's crazy to see how much your kids have grown from the first page of this post, when we all started following your thread, to now.

If he continues with this level of detail, the kids will probably be old enough to buy the champagne to christen the maiden voyage

 

[erover82]

We've never met other than in this forum, but it's crazy to see how much your kids have grown from the first page of this post, when we all started following your thread, to now.

I keep telling them to stop growing but they wont listen! Guess I'll just have to hang on to each day. Balancing life and projects isn't easy. Thankfully this project is far ahead of where it's documented here currently.

 

[erover82]

I've always loved the design of HCPU rear tailgates. LR never updated the Series tailgate when they designed the Defender, but I think if they had, they may have featured design elements such as the horizontal corrugations. I wanted to make this theoretical tailgate a reality, make it out of aluminum, and make it even stronger.

I set to work in CAD using a brand new factory tailgate for reference, retaining critical dimensions and design features while tweaking others to account for the increased material thickness due to the use of aluminum. The lower corner cappings and vertical stiffener were eliminated and replaced with HCPU-like corrugations that would also greatly increase horizontal stiffness. The rear (top when open) was also revised to be simply flat. The pressed stiffeners on the factory tailgate serve a purpose, but I wanted to be able to set items down without them rocking over.

Due to the way the sheets layer, the total material thickness in several sections would add up to nearly 5mm.

Components fabricated

Bonded, pressed, and clamped every way possible.

Fully cured and being test fitted.

Removed, sanded, blasted, and primed. Now it was ready for finishing along with the assembled rear tub.