Detours Off-road Hardware

XJ Tailbone Installation

Please take the time to read and understand the installation of the Tailbone System prior to your install, if at any time you have a question, please feel free to call us - 606-845-0024. Prior to installation, it would typically be a good idea to spray your factory bolt connections with a good penetrating oil well in advance, you'll need these connections to be serviceable, broken bolts or broken factory nut connections must be corrected prior to installing the TailBone system.

Confidence, we want you to know that each and every system is pre-mounted and installed to an XJ during fabrication, if the installation guide is followed, you should experience a smooth installation.

Painting, while your TailBone System arrives with a strong, durable primer-sealer finish, it needs to be 'top coated' with a paint of your choice, we do offer some suggestions on the Detours website.

Trailer Hitches, owners with trailer hitches will experience some additional work. The insert which retains your hitch on either side of the vehicle, will need to be removed and replaced with the supplied insert which works with the TailBone System, it 'must be used'. There are numerous hitch companies building units for XJ's, each company use's a slightly different insert, in any case the first 2 inboard factory holes must be unobstructed to allow the TailBone insert installation. This insert replaces the section of hitch insert you're removing and will be used to reconnect your hitch once installed. Longer 7/16" bolts may be required depending on hitch, and the supplied retaining plate will not be used, rather your hitch now acts as the retaining plate.

Your TailBone System will arrive looking like this when unpacked, all bolts are in-place, take note of bolt placement and part placement while unpacking, it's virtually assembled.

  1. Remove your old bumper from the vehicle. This is a good time to clean an inspect this area for damage and make proper repairs if needed. This is also the time to address and insert issues caused by the installation of a hitch.


  2. Locate and disassemble the supplied inserts. As you insert the unit, tip it upward and allow it to fall into the unibody area, you may move it around with a screw driver into position, loosely install undercarriage bolts into the unit to retain it in position.


  3. Existing bolt & plate in picture are a connections for a hitch, previously installed.


  4. Locate and lay in-place the 2 pinch lip connections and the center pinch lip connection aligning their holes to factory supplied holes in pinch lip.


  5. Lift the main rear cross-member into place, insert a bolt into the upper corner connection on either side retaining the cross-member loosely. Take your time and roughly center the cross-member to the XJ's body, insert remaining outboard bolts snugly (2), leave the inboard bolts very loose (4) - lift and locate the rear cross-member brace up into position between the fuel tank and factory cross-member, the 4 remaining loose inboard bolts must pass thru this brace within the holes provided. (while this can be done by yourself, the aid of a friend can be helpful) Once all 4 bolts have passed thru, retain cross-member brace with matching nuts provided.
  6. With rear cross-member in-place, complete the remaining connections with bolts provided, double check the centering of the main cross-member, tighten all connections including the nut connections (4) on the rear cross-member brace.


  7. Remove factory brackets from bumper skin, wash the bumper inside and out for best results.
  8. Find the center of your bumper skin, for this installation I simply measured from the inside of the bumper caps and found the 'this' bumper to be 59-3/8" overall, which made the center line of the bumper 29-11/16". (YOUR BUMPER CAN VARY, PLEASE TAKE THE TIME TO MEASURE)


  9. Mark your proposed center line on the bumper in at least two areas, using masking tape, provide yourself a center line from which to work from, noting which side of the masking tape references the center line.


  10. Using your established center line, you'll now need to locate the cuts required to fit over the recovery points of the Tailbone. The overall inside cut will be 37-3/4" when measured from cut to cut, measuring off your centerline, measure 18-13/16" in both directions and mark your bumper near the top face and lower portion of the bumper, see photo. (a 1/16" of an inch extra is being removed for clearance)


  11. Again off your center line, locate the outboard cuts. The external overall measurement is 39-5/16", so off your center line now measure 19-11/16" in both directions and mark your bumper near the top face and lower portion of the bumper, see photo. (again, a 1/16" of an inch extra being removed for clearance)


  12. Connect your marks with masking tape, plotting your cut lines to follow.


  13. As shown, from the top face edge of the bumper, measure down 1-1/4" and provide yourself reference marks, again connect these reference marks with masking tape, this marks the end of your cuts and your cross cut required.


  14. Now, with layout in place, position the bumper on top of the recovery points of the main cross-member for reference, your bumper should align within the tape sectioned areas, if not, adjust slightly as required.


  15. Correctly aligned, your ready to cut metal away from the area within the tape line. (use tool of choice)


  16. After cutting, check the fit.


  17. Each system comes with a left & right decal (L & R), these decals have been developed to provide you the hole locations which need to be drilled in order to mount the system, sandwiching your bumper skin in place. The decal with the "L" is for the LEFT side of the bumper, "R" is for the RIGHT side.Remove the backing 'ONLY' from the decal, apply the correct decal to the correct side of the bumper aligning it with the top edge of the bumper and centered over the area in which you just cut metal away from. Lightly apply the decal, allow it to lay FLAT, DO NOT force into the bumper's profile.


  18. Double check your decal alignment by placing to correct carrier mounting plate on top of the decal, push mounting plate firmly against the bumper and inspect the alignment of the holes in the decal making sure they line up within the holes of the mounting plate. Adjust if required.


  19. Drilling, we prefer to use step bits for this type of application, if you don't own a step bit, start with a 1/8" drill bit and give yourself a 'pilot hole', a pilot hole will help prevent a larger drill bit from 'walking', which helps with locating the drilled hole properly.
    a) Center punch your intended holes thru the decal, you want to be centered within the designated areas. (4 areas LEFT, 5 areas RIGHT)
    b) Drill a pilot hole (1/8" bit) if a step bit is not available.
    b1) From 1/8" now drill holes with a 3/8" bit, remove decal.
    c) Step bit, consecutively drill up to a 3/8" hole, remove decal.


  20. Test fit the bumper, now with 3/8" holes drilled thru it, check alignment to mounting plates on main cross-member, holes should align or closely align to threaded areas within mounting plates.


  21. Final drilling, if alignment looks good, drill all holes to their final size of 7/16", if you have alignment issues, drill holes to 1/2", if somehow you still have alignment issues, slot the misaligned holes vertically as required. (the 7/16" hole is the tightest possible hole for fitment, some may want to go directly to a 1/2" hole providing an easier overall alignment/fit) Checking alignment, thread all bolts into place.


  22. You're now ready to install the carrier mounting plates, using the G9 bolts supplied, bolt plates into position as shown. Bolt both plates loosely in position prior to tightening. A 9/16" box end wrench is required to tighten the 2 far left bolts on the hinge side. (RIGHT SIDE)


  23. Snug bolts up firmly, install the swing-out carrier and check for fit, you may need to slightly loosen the hinge side plate to allow some slight movement to create good carrier alignment when closed, snug the bolts back up on hinge barrel side after aligning. (Remember, your system has already been installed and alignment achieved, if you're having trouble, double check the instructions provided)


  24. Once alignment is achieved, torque the accessible mounting plate bolts to 65 ft lbs. The 2 bolts inaccessible with a torque wrench should be hand tightened with a box end wrench to the very best of your ability. (DO NOT slide a 10' pcs of pipe over the wrench and tighten until it breaks!) Re-torquing IS required, after your system has been completely installed, drive the vehicle for 10-20 miles, after this time- Re-torque the mounting plate bolts to 70 ft lbs, and rehand tighten inaccessible bolts to the very best of your ability. After a weeks time, check all exposed connections, if movement has occurred, a third re-toque may be required, 75 ft lbs.
  25. Lastly, the base of the bumper needs to be secured. Clamp loose bumper base to mounting bracket, using a 5/16" drill bit, drill thru the existing holes in the base of the mounting plate and drill thru the bumper itself, secure with bolts provided. (depending on overall fit, washers can be used as shims between the base of the mounting plate and the base of the bumper if a misalignment exists.


  26. Carrier mounting, pre-grease the carrier prior to final install, carrier retaining bolt should not be torqued, rather only a 'snug' fit only with Lock-Tite applied on threads. Retaining latch is to be installed and adjusted as required for a firm locking action, excess threads can be cut off after final adjustment. Tire mount simply slides and locks into place, adjust to your liking and backspacing, secure. D-Rings, this product is designed to accept 5/8" D Rings which offer 4.5 tons of retention each, we use a distributer by the name of Fastenall ( fastenall.com: The Leading Fasteners Site on the Net ), the part number is 43475, the cost is $12.90, they are American made. D Rings should be used with this product at all times.
    Your install is complete, this installation guide covers all years XJ's, 1997 and newer XJ owners will only need to adjust and re-secure their bumper end caps. As with all carriers, regular inspection of the product and it's condition should be part of your routine maintenance, greased regularly and bolt connections visually inspected and torque checked periodically.
    Again, questions during install? Please call us- 606-845-0024.
    Happy Trails and Thank you for choosing a Detours product!


*NOTE*- Detours can not and will not be liable for any individual who may have not fully read our directions provided and miss-cut or poorly cut their bumper skin to fit around the Detours Tailbone System. It is solely up to the vehicles owner to cut, trim and fit the bumper skin in a manner which the end result will look correct & professional.