High Clearance, Air Tank
for the Front Bumper

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Any trail ready off-road Jeep needs a place to store a full sized spare tire.  Typically the tire is mounted out back on a tire carrier and most designs are a swing-out type design especially if the Jeep has a tailgate and access to the tailgate is necessary to get to all the tools and spare parts stored in the rear of the tub.  Flipping through the catalogs, there are plenty of designs out there to choose from.  Anything from the basic carrier to full-blown rack systems with all kinds of places to store accessories.  Prices vary from a few hundred up to about a grand. I had an idea of what I wanted in a tire carrier.  It had to of course, carry a tire.  I also wanted a few other things out of it.  Like a place to carry the HighLift jack, a place to store other equipment like a chainsaw, a hollow bumper that could store compressed air, and maybe even mount up another hub assembly for spare parts and actually mount the tire to it.  It had to be strong so tow points could be mounted up.  A hitch assemble would be great too.  Well, now your talking some serious dollars for something like this if it even exists.  Well, if you have read any of the other tech write-ups on this Jeep, you would have figured that I decided to make my own.  So what follows is the general run-down of what was designed using a few basic tools, some scrape metal, some purchased metal and a lot of measuring, designing and welding.

Strengthening the Attachment Location on the frame

A concern about the weight of the rear bumper leveraging on the rear frame cross-member resulted in this re-enforcement of the rear frame cross-member.  It consisted of four 1/4 inch thick angles that fit into the frame's rear cross-member and anchored it to the frame.  This took the load off of the rear cross-member and put it onto the frame.  As a result, any leverage on the rear bumper due to the weight of the tire and any other accessories would be carried by the frame.

The bumper attached to the frame through two "C" brackets, one bolted to the frame using four grade 8 bolts and the other "C" bracket welded to the bumper.  The two are joined by 4 more grade 8 bolts, two above and two below on each bracket.  Simple yet strong and easy to detach.

The Design

Requirement number 1, the bumpers need to be hollow to store compressed air.  For strength the raw material for the bumpers, front and rear, were made from 1/4 inch thick, 2x4 stock steel.

Closing Off the Ends

To make it an enclosed chamber, I could have just welded plates to either end to cap off the cut lengths of 2x4 stock steel.  But what that lacks is style.  So a little "style" was incorporated into the bumpers by drawing an angle from the frame rails out to the ends, tapering it from 4 inched to 1 1/2 inches.  This also serves to increase approach and departure angles.

The scrap that was cut off to make the angle was then trimmed and used to enclose the lower sides.  Tack-welded on and the excess cut off.

This small piece was held in place while it was tack-welded on using a piece of electrical tape. Once the tack-welds were made the tape was removed.

This process was done by first welding up the seams as best as I could.  Then a NPT 1/4 inch hole was tapped into the bumper in the desired location.  A fitting was placed on the tapped hole and air was pumped into the bumper.  Air leaks were marked, the weld was ground down where the hole was and re-welded again.  Followed by more air tests.  I didn't worry about the micro-leaks (found only by putting soapy water over the pressurized tank.)  Later when all the welding was complete, paint primer was sprayed into the tank and then pressurized again.  This served to seal up the leaks plus coat the inside with rust preventative paint.  Make sure you let it dry for weeks (or longer) with the fittings off before using the tank!  You don't want to pump paint into your tires!

As mentioned above, for each side, one of two "C" shaped 3x3 sections were bolted to the frame.  The other of each pair was welded to the bumper itself.

Above: The "C" sections are being welded to the rear bumper
Below: The two halves of the bumper mounts.

The front bumper was mounted differently then the rear.  Two 90 degree angle iron pieces were welded so that they slipped into the frame rails, rather than mount outside the frame rails.

Anchored and welded

Mounted inboard of the frame rails (above)

Adding a Hoop to protect the Winch.  I had the hoop bent by someone with a pipe bender.

Fabricating a Swinging Tire Carrier

This is where some thought was required.  I wanted to use what steel I had but the swinging tire carrier had to be strong due to the stresses of an elevated tire.  Additionally the swinging section of the tire carrier had to carry a Highlift jack, and needed a way to mount possibly a future basket above the tire.  The design I came up with was a simple A-frame design with two attach points.  One point, on the passenger side, is where it would pivot on a single large bolt.  The other side is where it would lock down, again, on a single large bolt.

Base of the bumper drilled & mounted

The base of the swing will have these two bolts pass through it so the wall of the square stock 2x2 tube had to be strengthened.

This was accomplished by using flat 1/4 inch plates sandwiched around a piece of 2" pipe.  This "sandwich" was welded together, then inserted into the 2x2 stock at each end as seen to the right and below.

Then a 3/4 inch hole was drilled through at each end to allow the 3/4 inch grade 8 hardware to pass through.

This is how the swing is held in place.  At either end, a "L" shaped piece of angle iron is welded to the back and the bolt passes through the top, through the base of the swing and into a 3/4" nut welded to the bumper.

Test fit.  Later a bracket was bolted on to hold the Highlift and a Highlift accessory bolt-down clamp was purchased from Highlift and installed to hold the Highlift in place.

A plate was welded in the center of the A frame so that a hub assemble could be bolted into the center to hold the tire.

When welding these sections together, I should have left them cool somewhat before proceeding to weld it all together.  The angle, after cooling, pulled the bottom swing arm up causing it to bow about one inch from side to side.  It still fit into the bolt holes on the bumper but it arched up and I had to push it down to close the swing arm on the Jeep bumper.  Later it actually fit better because of the arch.  I was glad to see that.

A tube was welded to the base of the swing and holes drilled in the support (picture at right).  This is a way to lock the swing-out with a bolt so it doesn't swing freely when opened.

In the center of the bumper underneath, a plate was welded on that a Reese hitch can be bolted to. For trail use the Reese hitch remains stowed away, only to be bolted up if needed.

Another addition was to weld on 4 - 3x2x1 inch blocks with a 1 inch hole drilled in it. These held the shackles for tow points for recovery.

Everything was then, painted up and installed.  While it was an investment in time, it also was fun designing my own bumpers.  Another custom modification for the 78 CJ-7.

Below are several modifications to the rear bumper that I did after the initial build.

Upper Storage Rack

During the initial design process, I designed in a vertical support that I could later bolt a storage rack to.

To the right is the rack I came up with.  This shallow, low profile design is great for rear visibility.  The perimeter is 1 1/4 X 1 1/4 inch 16 gauge galvanized steel bolted into a rectangle.  The base is a heavy steel mesh.  I have corner pieces bolted in under the mesh for support and to keep it square.  The rack actually rests on the tire for center support.  Holds were dripped in the frame for bungee hook points.  This rack is then bolted to the tire carrier to that "T" you'll see in the pictures above.  (That "T" is actually a cut bed rail, perfect size and strength.)

The rear corners of the rack are held up by two vertical supports (same material as the rack frame) that run from the rear corners of the rack to the lower swing arm.  They're attached by a 16 gauge piece of steel wrapped around the swing arm.  (See Right).  The yellow is yellow electrical tape wrapped around the swing arm. 

I've seen several designs for a rack, most of which had at least a 4" side to hold the cargo. This low profile design is actually great for holding gear like my Chainsaw or a cooler.  I always have a supply of bungees and with plenty of attach holes, I've never had a problem with loosing gear on rough trails.

To the right  you can see the vertical support.

Another addition was a CB antenna and mount.  For about 15 bucks I picked up this CB antenna mount from my local CB shop.  I also invested in a good quality 12 foot coaxial extension to run from the CB antenna to the CB up front.  The antenna I used is a 4 foot fiberglass stick antenna.  I DID NOT use a spring base on the antenna.  A spring will do nothing but allow the antenna to whip around and smack the soft top and any cargo I'm carrying in the rack.  The fiberglass antenna is strong enough to flex very far without any issues while offroad.

Above and below are a few of shots of the lower left of the bumper and swing arm.  As covered above, the swing are is secured by a large 3/4" bolt with a "T" welded onto the top of it.  The "T" is just another long bolt, no threads or hex head, which I cut off.

Here's a couple shots below of the tire carrier bumper while opened.  On thing to notice is the "L" shaped bracket that attached the Highlift to the bumper.

The highlift bracket that clamps down the Highlift jack is made by Highlift itself.  I made the bracket that holds the Highlift clamp bracket to the bumper.

To the right, Utility Lights, one at each side mounted on the front side of the rack with a piece of the same material as the rack frame.

To the right is one of the four D-ring tow points welding onto the bumper.  These were 1" x 2 1/2" x 3" solid steel stock with a large hole drilled in it for the D-ring.

I didn't use my 300 dollar welder to weld these onto the bumpers.  Instead I borrowed took them a friends steel shop and used his professional grade MIG welder.  Because if the importance of these tow points being strong, I didn't want to chance not having a good weld here.

IMPORTANT Design Addition:

As far as weight goes, this rear tire carrier with cargo, 33" Super Swamper, Steel Rim weight a lot.   Over time the holes that the 3/4" bolts run though in the swing arm began to get larger from all that weight wobbling while offroad.  At first it was quite tight but over time, the holes opened so that the tire carrier would wobble a good inch or two forward and backward.  So a plan had to be devised to stabilize the tire carrier.  So a 1" x 1" square stock rod was installed as seen to the right.

This Rod would meet up with a simple angle bracket bolted to the tire carrier.  The two would be connected with a wing-nut bolt.

Below are the two attach points for the square stock rod.  I used a 1 1/2" rubber spacer and ran a long grade 8 bolt through the Jeep tub where I already had a bolt through to hold the rear armor onto the Jeep tub.  These bolts run through the rod and are bolted on.  The downside of this is I have to remove the rod to drop the rear tailgate but it only take a minute to remove it.

This design is simple yet it made a world of difference in strength of the tire carrier.

The tire was attached to the tire carrier with a spare front spindle and hub assembly that would fit my rig if I ever need it.

Another mod that I actually did earlier when the bumper was being built. At the center of the rear bumper, I welded a pre-drilled, gusseted steel plate so that I could bolt on a Reese hitch.  If ever I need a hitch, I have a place to bolt it on.  Typically the hitch is not bolted on and the plate isn't an obstruction offroad.  

• Onboard Air Intro
    
• York Installation
    
• Bumper Air Tanks
    
• York Identification
    
• Hand Throttle

Project Jeep CJ-7

Custom bumpers

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