How To Build A Custom Jeep Wrangler YJ Alternator Shield

Materials Needed
  • 12″x24″ 26 gauge sheet steel (pretty thin, just like heat duct metal)
  • 1/8″ pop rivets
  • Spray paint and primer (optional)

Tools

  • Air cut-off wheel (tin snips or hacksaw would work, but not as well)
  • Hammer
  • Rubber mallet
  • Pop rivet gun
  • Socket set
  • Drill and bits
  • Clamps
  • 2 large boards (for making clean bends)

Preparation

The first thing I did was remove my alternator. Then I assessed the situation and decided the first thing I needed to do was find a mounting point for the shield. I choose the alternator mounting bolts (2).

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

The next step was to figure out how to get the steel up to the bolts and still leave room for the alternator to breathe and not overheat. Unfortunately, I didn’t get a picture of this so I will do my best to explain and the next pictures will help you understand.

The first bend was to fold the sheet in half longways. To do this, I placed the sheet in between the 2 boards and clamped them together on the centerline. Then I carefully bent the sheet by hand until I could hit it with the rubber mallet into a 90 deg. bend.

Take it out of the boards and finish the bend completely in half. Now you have to make a mark two inches from the folded edge down the whole length (longways again) This is going to be your next bend line.

Place it back in the clamp/board vice and bend one edge one way and the other edge the other way, using the rubber mallet to make the corners crisp. Now it should look kind of like a “T” (although short).

Building the Shield

At this point, you should have 4″ wings (top of the “T” on either side of a 2″ rise. With the alternator put in place, loosely place the “T” in the engine compartment to see where you’ll need to make cuts for bending.

I also forgot to measure these but it’s really easy to visualize when the “T” is in the bay. I would say that there was that the first one was about 8″ from the top, the next one was 5″ from that and the last one 8″ from that, this allowed for about 3″ at the bottom. Below is a photo of the shield that might give you a better idea.

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

In that photo, you will notice the cuts that I had to make to be able to bend the “T” around the alternator. I used “V” shaped cuts to allow for easy bending and used the boards and clamps creatively to make the bends straight.

After you’ve marked your spots for the cuts (don’t use my guesstimates without first test fitting). I would take the chance to put in some pop rivets to hold the “T” in place. I choose to keep my rivets as close to the inside edge as possible (near the wings).

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

You’ll see in this photo that I had to remove most of the center section. I left enough metal for the rivets to still be in place. Make sure that you leave room for the mounting holes (also visible in the photos).

Installing the Shield

There are a few other cuts that you will need to make at this point to clear things (A/C mounting bracket, fender, wiring, etc.). I won’t get into much detail here because your options may be different than mine and your bends may be a bit different. I had to cut a space to clear the A/C mount (I do not have A/C). Here’s a photo of that cut:

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

You can see the cut at the top of the photo. The tab that you see on top of the factory A/C bracket is going to get a bolt through it for more support. I also choose to fold over the last inch or so of the front to help a little more from the front and reduce some clearance issues (not as sharp either).

In this photo, you can see the bottom and final bend. I took the last 3″ or so and bent them up towards the engine to help bottom splashes. I also attached a strap to help support the shield and to keep it from shaking while the engine is running:

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

I’m laying under the jeep with my head towards the front bumper. I also drill several weep holes in the bottom corner to allow water to drain. The strap attaches to a long bolt on my oil pan. I just sandwiched it between some washer and another nut. (Oil pan nut, washer, strap, washer, nut)

Final Touches

I rounded off sharp corners and smoothed out edges and then I primed and painted it white. Let it dry and then installed it all The mounting holes on the shield should be sandwiched between the starter and the brackets on the front side of the alternator.

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck GuideMake sure that your new shield clears anything important such as belts and body panels to keep rattles away. Here are a couple of photos of the shield installed.

, How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

The last photo is from the side of my jeep kind of at an angle. The left side is more like the top of the engine. I hope this gives you some ideas on how to protect your alternator from water and mud and potentially leaving you stranded., How To Build A Custom Jeep Wrangler YJ Alternator Shield, The Truck Guide

Good luck, I hope your results are better than this! Make sure you do your due diligence before attempting any of this of course.