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Thread: Rear Bumper Removal / Hitch Mod (for oversized spares)

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    Senior Member Getting Dirty hoaxci5's Avatar
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    Rear Bumper Removal / Hitch Mod (for oversized spares)

    http://jeepdex.com/Commander/DOCS1/HitchIns.pdf

    Mostly correct, but not totally. I didn't document this as well as I should have, but here it goes.

    There are 4 "pop top" fasteners. I used a flat head screw driver to pry up the pop part, and then pulled the whole fastener out.


    There are 2 torques (?) screws one on each side


    At each fender flare there are 2 pinch type fasteners, I was able to pinch them laying underneath the jeep to release the bumper from the fender flares.


    These two fasteners are what took me a little off guard, this is what Jeepdex doesn't show.
    These two fasteners (2 on each side of Jeep) the center section pops out, I don't think they have to be removed completely but I did. This releases the the whole metal piece.


    I don't think I have pictures, but there is 1 plastic rivet on each side where the bumper connects to the fender flare, I used a screw driver to push the rivet through and then pulled the remaining part out. Once all of that is complete, you should be able to remove the bumper cover. Once the cover is removed there is a plastic bumper underneath, from under the Jeep there are 2 more pop top fasteners. Then the plastic bumper can be removed.
    This exposed the rear hitch. Make sure the spare tire is dropped and remove the 4 bolts.


    I had already cut down the bolts and hitch so I don't have before and after pics. But basically you can go all the way to the welds, there is a lot of extra material there just because they didn't bother to remove it. So here is an after pic with paint.


    And another


    So the whole point of this mod is to allow for a larger tire to fit in the stock location, I stole the idea from Nathan (Omelet) but he didn't have a good write up.. So I (we) used carriage bolts in place of the stock Nut/Bolt setup. The OEM hitch had the nuts spot welded on to the hitch. I used a 3 lbs sludge hammer to remove the nuts, it didn't take much, but I wasn't thinking and did break my 7 pin cover. So I'd suggest removing that before hammering.

    Once you have removed the nuts, replace the nuts and bolts with 1/2" x 4" carriage bolts and matching nuts. I used nylon locking nuts which I think was a mistake. I had to spot weld the carriage bolts so they wouldn't spin. Nathan said he was able to tighten his down without welding... These bolts are smaller than factory bolts, so I don't know if that degrades the towing capacity, I hope not, and it seems that really the bolts are just holding the hitch in place and really taking any of the force since the frame is there. I'm interested to see what someone else with some engineering background (cough MATT cough) has to say on this..

    But the final product makes for a pretty much flush mounted hitch so that an oversized spare can fit. I don't have a final spare in location pic, because I'm still waiting for my replacement spare tire hoist winch which should be here later this week and maybe I can update then.
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  2. #2
    Lifetime Member Getting Dirty Matt's Avatar
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    1) +1 rep points... i gotta do this

    2) Another trick to keeping those bolts from spinning is a jab of JB-Weld underneath the head (assuming you have some time to wait for it to cure) if you don't have a welder

    3) I believe this piece is "hanging" on the frame with all of the bolts in double-shear. Decreasing the size and grade of the bolt will reduce their overall load capacity.... however, if you're just replacing the middle two bolts and retaining the OEM outer two bolts, it's probably not reduced by a significant amount. I'm sure it's OK, especially since these parts tend to have a ridiculous safety factor built in to account for degradation of the bolts & frame for the life of the vehicle, and some planning for stupidity (there's always someone out there that'll grossly overload it). Do you know what size the stock bolts are?

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    Lifetime Member Getting Dirty Matt's Avatar
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    Founds Omelets pictures. The hitch is hanging so the bolts are taking load. This shows it pretty good:





    For piece of mind you can get 1/2" x 4" grade 8 bolts instead of grade 5.. they're called Shaker bolts:

    http://www.fastenal.com/web/products...0167164&ucst=t
    Last edited by Matt; 01-29-2012 at 07:36 AM.

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    Senior Member Getting Dirty NeilSmith's Avatar
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    I also thought about doing this mod. What I havent checked out yet was how far my receiver and hitch basket go up into the hitch. If they protrude through too far than it would make this mod a waste of time. So, you may want to check this first and see if you can cut them down also.
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    Senior Member Getting Dirty hoaxci5's Avatar
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    http://www.rockcrawler.com/techrepor...ners/index.asp

    If I'm not mistaken, this is showing that each of the 1/2" bolts can take 14730 lbs shear capability, if that's the case there should be nothing to worry about correct? A hemi is only rated to tow 7200 lbs, and I understand force is different than dead weight so starting and stopping will put a larger force than the weight of the trailer. But in theory one bolt should be enough to handle the full towing amount. (Obviously I'm not recommending that, just a point of discussion and I'd like to feel safe towing..)

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    Lifetime Member Getting Dirty Matt's Avatar
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    Quote Originally Posted by hoaxci5 View Post
    http://www.rockcrawler.com/techrepor...ners/index.asp

    If I'm not mistaken, this is showing that each of the 1/2" bolts can take 14730 lbs shear capability, if that's the case there should be nothing to worry about correct? A hemi is only rated to tow 7200 lbs, and I understand force is different than dead weight so starting and stopping will put a larger force than the weight of the trailer. But in theory one bolt should be enough to handle the full towing amount. (Obviously I'm not recommending that, just a point of discussion and I'd like to feel safe towing..)
    Yes/No... it gets a bit more complicated when you start taking into account fatigue cycling and other factors.

    Did you replace all 4 bolts with grade 5 carriage bolts? If so, I'd probably swap them out for the grade-8s i linked for peace of mind. If you only replaced the center two, don't sweat it but it couldn't hurt to throw those better bolts in there.

    From your own link:
    “When in doubt, make it stout!”

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    Senior Member Getting Dirty hoaxci5's Avatar
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    Ugg.. once I get my replacement spare tire winch I'll have to take a look and see if the two outer bolts would hit or not.. I might just put the originals back in.

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    Lifetime Member Getting Dirty Matt's Avatar
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    What size spare are you running? I recall seeing that for the outer two you just need to cut off the excess bolt to fit a 265/70/17 in there...


    Edit: and another idea for those who can weld... clean up the area and throw some fillet welds around there to add support. Dont see a reason you'd want to permanently remove the hitch (and even if you did, you could grind the welds off)
    Last edited by Matt; 01-29-2012 at 12:30 PM.

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    Senior Member Getting Dirty hoaxci5's Avatar
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    255/75/17

    My welder (and skill) isn't good enough to trust for a project of this importance.. so I'll check it out and update once my winch is here which should be Tuesday.

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    Lifetime Member Getting Dirty Matt's Avatar
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    I meant welding in addition to the bolts.

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