Fabricating a Gas Tank Skid Plate for a Jeep Cherokee

The fuel tank on Jennifer’s XJ has taken quite a beating from off road driving. In fact the fuel pump pickup is no longer the lowest point in the tank making the effective size of the tank much smaller than its original 20 gallons. She will need a new tank to cure this problem but in the mean time, I decided to fabricate a skid plate to prevent further damage and to be ready when she can get a replacement tank.

I began by making a mock up out of foam construction board. The pieces I had had once been a sales display. It provided several large sheets of ¼” poster board with a foam liner. The material is stiff, lightweight and easy to cut and draw on.

I looked at several skid plates commercially available and I did not like the way they mounted. I wanted something that attached to the unibody frame rails one either side of the tank. Of all the ones I looked at, only the Mopar plate mounted like that.

I began with two pieces of 3x3x1/4 angle. I cut them to extend from the front of the trailer hitch to the front of the tank. I shaped the upper flange to match the shape or the curved frame rail section. I drilled holes in the angle face and then made corresponding holes in the Jeep. I tapped the sheet metal for 5/16 bolts. I used the existing exhaust hanger bolts on the passenger side as well.

Using the template I made from foam, I cut two side plates form 3/16 scrap. These extend the angle down to level with the lowest point on the tank. They are angle d at the rear so that I could mount a plate angled up behind the gas tank to protect the rear of the tank and not take away departure angle. I ended the rear late below the trailer hitch cross bar.

I then welded the extensions to the vertical parts of the mounting angle. I bolted the side pate to the Jeep temporarily and confirmed the measurements of the two main plates. I put one large plate under the main part of the tank and second plate going up at an angle at the rear of the tank. The fabricated angle between the two plates adds a lot of strength.

I tack welded the bottom plate to the side plates. I then took the assembly down and finished welding the bottom to the sides. I then welded the back plate to the assembly. I made a series of short welds along the long seam to avoid warping the metal.

Once the welds were finished I ground the edges smooth and painted it black.

Putting the entire assembly back up took some help as it was now too heavy to balance on one hand. Jennifer assisted me by balancing it on the under lift stand. She also helped move the exhaust pie out of the way while I started the bolts. Only one of the 5/16 – 18 bolts stripped in the thin frame rail. The others tightened down well. I drilled and tapped a new hole to replace the one that stripped.

I plan to replace the tapped holes with nut rivets in the future if these do not hold. The skid plate is very sturdy and neatens up the appearance of the rear of the Jeep. I think I will have to make another one for my Jeep now.