Crawler Conceptz Ultra Series II JK rear bumper & tire carrier installation, part one


As anyone who’s had the chance to see their work up close knows, Crawler Conceptz is quickly making a name for itself in the Jeep aftermarket industry, thanks to its quality products and design creativity.

The Ultra Series II rear bumper and tire carrier for Jeep JK are no exception. Installation of the bumper is relatively straightforward, which is fortunate, as the only instructions included are for the tire carrier portion of the installation. (As a young company, such growing pains are inevitable, if frustrating.) As a substitute, I made use of the instructions for a competitor’s similar product and a video showing installation of that product.

Even then, the installation was not entirely without its minor hiccups. They’ll be noted below, where applicable. NOTE: This installation write-up assumes the installer has performed an initial test-fit prior to paint or powder coat.

Materials/tools needed:

  • 3/8-inch socket handle
  • 5/8-inch socket
  • 3/8-inch socket extension
  • 1/2-inch socket handle
  • 3/4-inch socket
  • Grinder or Dremel w/cut-off wheel
  • Wax pencil or permanent marker
  • Center punch
  • Drill
  • 1/2-inch drill bit
  • 1-inch drill bit or hole saw
  • Basic cleaning supplies
  • Masking tape
  • Primer
  • Touch-up paint

Step 1: Remove OEM bumper

Using a 5/8-inch ratcheting socket, remove the Jeep’s Tupperware, er, factory rear bumper. It’s held in place using two bolts into the frame rails in each rear wheel well, and by four bolts in two brackets in the rear frame cross member. You’ll need to climb down under the rear of the vehicle to access these. (Make certain the muffler and exhaust system isn’t hot to avoid a nasty burn.)

The rear bumper weighs about 15 pounds, and is easily removed by one person.

Step 2: Remove tow hitch wiring tab

HitchThe Ultra II is notched for use with the factory trailer hitch, but one of the bumper’s mounting tabs is positioned to hit the bracket that holds the wiring harness in place. (at right, circled in red) The bracket is welded to the hitch, and must be ground off. While this was my first real frustration with this bumper, I’d be remiss if I didn’t at least note it was also at least partly one of my own making. I’d chosen the factory-hitch version of the Ultra II precisely because I’d believed it would maintain this very mounting tab — and I didn’t want my wiring dangling down below the Jeep. I should have asked for clarification, in which case I’d likely have gone with the integrated-trailer-hitch version of this bumper.

I removed the four 3/4-inch bolts holding the hitch in place (Surprisingly, three of these bolts were little more than hand tight!), and ground off the L-shaped weld holding the tab in place. After a little clean-up grinding for appearance’s sake, I covered all remaining bare steel with two coats of touch-up paint to prevent rust.

Step 3: Drill frame to accommodate bumper

Slip the bumper in place, and install the factory bolts hand tight. Mark the location for the third bolt hole in each wheel well. If you plan to utilize all four cross-member mounting locations, mark the center two holes as well. (In the absence of printed Crawler Conceptz instructions, I relied on an instruction from “that other company” saying to ignore the two centermost holes.)

Remove the bumper, then measure three-quarters of an inch to the outside of the existing half-inch hole along the outside of the rear cross member. Mark the location and drill a one-inch hole centered on this mark. Use primer and paint to cover all areas with exposed steel to prevent rust from forming.

NOTE: It may be necessary to enlarge the factory holes later. Use your best judgment whether or not to enlarge them at this time or to make adjustments after the tire carrier is in place.

Step 4: Insert clip nuts

Insert the clip nuts in the outside of each frame rail and in the bottom of the frame cross member.

Insert the clip nuts in the outside of each frame rail and in the bottom of the frame cross member.

Slide the included clip nuts into the large factory holes in each frame rail and into the large holes drilled into the underside of the cross member so they straddle the inner and outer sides of the Jeep’s steel frame. The extruded portion of the clip nut should face INTO the frame rail and cross member.

It may be helpful to use the claw side of a small hammer or another hard, flat surface to drive the clip nut into position. The clip nuts may create surface scratches in the frame’s finish. Use touch-up paint to cover these exposed areas to prevent rust.

NOTE: Make sure there is room forward and rearward movement, as adjustment may be necessary when the tire carrier is mounted.

Step 5: Final installation

With the help of a friend, slide the bumper back into position, taking care at the trailer hitch, as the bumper will need to be rotated up to clear the hitch receiver. Use the factory 5/8-inch bolts and four 9/16-inch bolts and washers to secure the bumper in place. If you’re proceeding on to the tire carrier installation, I recommend leaving all these bolts somewhat loose for now to allow for adjustment.

As my schedule was forcing me to stretch installation over several days, I covered the exposed steel of the carrier spindle in electrical tape to prevent exposure to the elements.

UP NEXT: Part two — installing the tire carrier


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