WJ Rear Stubby Bumper – Installation Instructions

Trail Forged WJ Rear Stubby Bumper

Installation instructions for the WJ Rear Stubby Bumper.

Installation should only be performed by an experienced fabricator. If you do not have all the necessary tools, experience, or confidence to undertake this project, please seek help before beginning.


Note: These instructions begin where our WJ Lower Quarter Panel Replacement – Installation Instructions leave off as they share much of the same process to this point. Your starting point will be similar to the below picture with the quarter panels tucked (we advise the use of our kit, but that is not a requirement for this installation).

Final stage of lower quarter panel replacement installation and beginning stage of rear stubby bumper sheet metal removal


REMOVAL OF SHEET METAL

Starting where the quarter panel installation instructions left off, the next step is to begin marking and cutting the sheet metal below the hatch itself.This is where the stubby bumper will sit.

  • Draw a horizontal line across the entire bumper structure above the top bend and below the hatch.This line should line up with the cut lines beneath the tail light.There are two pieces of sheet metal here; you are only cutting through the first layer at this time.
  • Draw a second horizontal line at the bottom of the structure, directly above the spot welds.
  • Locate the spot welds for supporting panels on the left and right corners, out near the outside of the frame rails (orange dots in the picture below).Draw a cut line just outside of these spot welds (white line in the picture).
  • Cut all 4 drawn lines and remove the center structure.

Upper and lower horizontal cut lines

Remove center structure after cuts

  • On the bottom horizontal face of the remaining center structure, draw a line beginning 1/2″ rearward of the outer mounting nuts, and converge toward the center of the structure behind the spare tire well, leaving approximately 1/2″ of the flange in tact at that point as pictured.See red cut line and short yellow lines in picture below for distance references.
  • At the center of the remaining structure, draw a square approximately 3″ wide transitioning up the back face near the spare tire well, terminating it with a horizontal line approximately 1/2″ below the factory cutout.
  • Cut the bottom flange along this line and remove excess material. The square section allows needed clearance for hitch of the stubby bumper.

Yellow lines indicate approximate distances noted above

Removal of bottom flange and excess material

  • Remove tabs on each side to match upper and lower cut lines.See red cut line in the photo below.

End result after removal of side tabs

  • Sheet metal cutting is complete.The rear should now look as seen in the picture below.The remaining material will help support the lower seal area of the hatch.We recommend painting the bare sheet metal at this point for rust protection.

Final state of sheet metal before installation


INSTALLATION OF BUMPER

At this point, assembly of the complete rear stubby bumper is assumed to be completed and all components painted and ready for install.

Included hardware:

  • (6) 7/16″-20 x 1.5″ bolts with washers
  • (6) 7/16″-20 x 2″ bolts with washers
  • (4) 3/8″-16 rivnuts
  • (4) 3/8″-16 x 1.25″ bolts with washers
  • (9) M12 x 1.75″ x 40mm bolts (Optional add on – necessary if you do not have a factory hitch)

Bumper Mounts –

  • For installation of bumper mounts, the fuel tank must be unbolted from the frame rail and lowered to allow the mounts to slip in between the frame rail and fuel skid plate. This can be done one side at a time so the fuel tank does not have to be balanced fully unbolted.
  • Slide bumper mount into location and temporarily bolt in place using M12 bolts.Seat the outside face of the bumper mount fully inward against the frame rails and tighten hardware.
  • Use pen to mark location of (2) rivnut holes on to the side of the frame rails.
  • Remove bumper mount and drill slightly over-sized 1/2″ hole at the marked locations in the frame rails.
  • Insert rivnuts into drilled holes (see rivnut installation procedure here).
  • Re-place bumper mounts for final installation using all M12 hardware and (2) 3/8″-16 x 1.25″ bolts and washers per side into the new rivnuts.Leave bolts loose to be torqued later.

Stubby Bumper –

  • Place stubby bumper over the protruding bumper mounts.Use farthest inward bottom hole and 7/16″-20 x 1.5″ bolts with washers to loosely secure stubby bumper to bumper mounts.
  • If you purchased D-Rings, hold them up and loosely install remaining bottom 7/16″ bolts and washers.
  • Install (3) 7/16″-20 x 2″ bolts with washers on each side and torque to 58 ft-lbs.
  • Tighten all bottom bolts and torque to 58 ft-lbs.
  • Torque all bumper mount to frame rail hardware.Torque specs: 3/8″ – 25 ft-lbs and M12 – 65 ft-lbs.

Under-view of bumper mounts and stubby bumper with D-Rings (bottom tab of D-Ring not shown here)

Profile-view of completed installation

Rear-view of complete stubby bumper with D-Rings


Notes: These instructions are meant to be a general guideline and not a factory certified service procedure. We are not responsible for any failures or issues that may arise in others’ installs. This product is intended for offroad use only, vehicle owner assumes all responsibility by purchasing and/or assembling and installing this product.

Leave a Reply

Your email address will not be published. Required fields are marked *