Before we begin cutting and welding, it is IMPERATIVE that your measurement was correct in Part 2, and your tape line is also correct. If you do not have the correct measurement for your cut, your axle will NOT weld back together correctly, and serious damages may occur. Anything can go wrong with a crooked axle from fried bearings every few miles, all the way to snapping the axle off where you welded it due to serious amounts of stress. You do not want to risk it. Make sure you are dead on with your measurement BEFORE you make your cut.
In addition to measuring correctly, it is also important that you are comfortable performing these steps. If you are not - DON'T DO THEM!! You can easily hire someone capable of doing the job correctly. There is no shame in calling in a pro, especially when it involves the safety of you and everyone else around you.
Safety is paramount. You should be wearing every bit of proper protective equipment when performing these steps (as well as any others). Please ensure the safety of you and everyone around you when cutting and welding.
The significance of the tape is to identify the edge of the cut. Remember, there is supposed to be exactly 2 7/8" BETWEEN each tape edge. If both pieces of tape are on the right side of both lines, there will not be 2 7/8" between the lines.
The edge of the tape lines will allow you to make a cut swiftly, straightly, and help avoid blade width compensation when making your two cuts.
For the sake of ensuring you have the correct measurement, DOUBLE CHECK ONE MORE TIME that you have exactly 2 7/8" between the tape lines as shown in the picture below.
Make your first cut between the tape lines using the tape line as a guide. TAKE YOUR TIME!! Ensure the cutting tool remains as perpendicular (90 degrees) to the tube throughout the cut. It is also a wise idea to have someone catch the cut off piece when it falls. Your first cut should be the outermost cut. This will leave the remainder still attached to the axle tube, which allows for an easier second cut.
This pics below demonstrates the significance of the tape line. The blade width did not have to be compensated for because the tape edge provided the reference for the outermost section of the cut. The blade width has automatically been taken away from the inside of the piece being removed.
This should be your end result. If you measure your cut piece, it may not measure 2 7/8" - and that's OK. On average, it is anywhere between 1/8" and 1/4" shorter than measured. If it measures 2 7/8" or more, you likely messed up somewhere.
Now it is time to clean up the tubes and prep them for welding.
Before you grab the prep tools and cleaners, take a moment to add a notch to your reference line created in Part 1.
You can simply take the cut off wheel on the grinder to trace out a small portion of the line at each edge on each tube.
This will allow you to keep the clocking reference while cleaning off the marker line.
It is very important that you do not lose the clocking reference. It will be very difficult to get it lined up again.
To ensure a strong weld can be made to the tube, and penetrate the metal properly, add a bevel to the edge of each tube.
DO NOT bevel the edge all the way down to, or past, the inner tube.
A good rule for a bevel is 50-70% of the thickness by 1x the thickness back.
Cleanliness is key to a strong weld. Bare metal and free of grease, oils, and contaminants will ensure a strong weld.
We used nothing more than emery cloth and acetone to clean our metal before welding. Be sure to thoroughly clean the inside of the tubes as well as the outside of the tubes. No contaminants should easily enter a weld area when they can easily be removed with a few wipes of a cloth.
One popular mod for the Ford 8.8 is strengthening the axle tube to housing connections. The axles are held into the housing with nothing more than a few pins. It is possible to break the axle pins and spin the tube. Typically, you won't be threatened by this unless you are in the extreme racing world performing hard launches with extremely sticky tires being driven by a ton of torque. The off-road world also sees this issue. There is a solid upgrade if you feel you need it, or just want to do it anyway: weld the tube to the housing.
This needs to be thoroughly cleaned as well on BOTH sides (both tubes). Feel free to weld them at any time after prepping and cleaning.
You will need something to hold the axle tubes together in the correct placement while you measure, tack, and weld. This should NOT be done by hand. An axle jig is an excellent tool to use, but they do carry a price tag. Sometimes you can buy them ans re-sell them afterward, but let's face it - if you aren't planning on narrowing axles often, this is an expense you could easily avoid.
Channel iron is an excellent shape of metal that will allow you to clamp the axle tubes together while measuring, tacking, and welding. A minimum of 2 pieces of 3" channel iron and 2 strong C clamps are required.
DO NOT weld the channel iron to the axle tube for placement. Welding causes distortion in the metal and may knock the concentric placement out of line resulting in a crooked tube. Use clamps!
Place one piece of channel on top, and one piece on bottom. Clamp the inner section of the axle to the channel firmly, but do allow enough slop to slide the outer section of the tube in. Once you line up your reference marks, clamp the outer section in place firmly, then re-tighten the inner section.
Now you must ensure the axle tube is the correct length. MEASURE AS MANY TIMES AS YOU NEED!! Both sides of the axle should be the exact same length.
If your measurement is too long (longer than the passenger side), you need to remove small amounts of metal from one tube so you can bring the tubes closer together.
If your measurement is less than the passenger side, you cut too much. It is highly recommended that you start over with a new axle. We do not in any way, recommend "gapping" an axle tube weld. You could go to the junk yard and cut off an extra passenger side axle tube. Do the job once - do the job right.
After you have verified your measurement, place a tack weld on the tubes, 180 degrees apart.
Rotate the channel iron and clamps 90 degrees, and place 2 more tack welds 180 degrees apart.
You should now have a tack weld at the 12, 3, 6, and 9 o'clock positions holding the axle tube in place.
DOUBLE CHECK YOUR MEASUREMENTS!!
You should have the exact same measurement at every point on the axle tube. If you do not have the same length, you have a crooked tube. You will need to cut the tacks and shave down the side that shows the longest measurement.
Once your measurement has been verified as many times as possible, weld it.
After the weld cools, measure again to ensure the axle tube is straight. If it is not, suck it up, and do it again. There is NO REASON to put a crooked axle on your vehicle. You WILL end up paying for it in the end.
The final step is to clean the weld up.
Questions or comments about this section? Post them below or Email The Fabricator
Part 4 of a 4 part How-To series demonstrating how to narrow a Ford Explorer 8.8 Rear Axle. This section covers the selection and installation of perches and accessories required to install the now narrowed Ford Explorer 8.8.