This how-to assumes that you will be using sway-a-way height adjusters. You will need to buy four instead of the usual two. You will also need two ball joint beams, one must be in good condition; the other can be in poor condition.
What you are doing is cutting a beam in half, welding sway-a-way adjusters to the cut ends and welding in spacing tube made from a second beam (see photo). You are then cutting up four sets of torsion leaves to make four (slightly longer than) half width torsion leaf sets.
In the middle of the stock beams is a casting through which the torsion leaves pass, anchoring them in position at their centre. A grubscrew and locknut holds the leaves in position. Most of our work revolves around these anchoring castings.
First, disassemble the beams completely. You can leave the needle bearings in position, but protect them with a rag. When removing the leaves, keep the leaf packs together with a tie-wrap or some tape, and note their position and orientation (left hand side VS. right hand side / top VS. bottom). This is important!
Take your good beam. Cut it to the left and to the right of the central leaf anchors as if you were just inserting adjusters. This normally means cutting one inch left and one inch right of the central grubscrew. However, check your adjuster's instructions or measure the width of your adjusters and cut that much out. Note that you cannot use the trick of cutting and welding the top then moving on to the bottom in order to keep the beam straight. You must completely cut up your beam and use your own skill to keep the thing straight.
The tubes are best cut with a pipe cutter, however you will probably find that you cannot rotate a cutter due to the closeness of the tubes. You will therefore need to cut the tubes with a hacksaw.
The trick is to use a good hacksaw with a new blade, and use a good quality stainless steel jubilee clip around the tube to guide the blade.
You will now have two beam halves. You now should consider how much longer your beam is to be.
You have two factors to consider - both related to the position of the adjusters. The adjusters must not foul the position of the beam mounts (if you are using these) and must not foul the mounting position of the steering box. If you have any additional beam supports fitted to your car then think about where these clamp to the beam, too. If it helps, draw it up full size on a piece of wood or cardboard tube and position it on the front of the car to check that it is going to work and nothing is going to foul.
You should now know how big your beam is going to be, and how big a gap you are going to have between your adjusters. You need two pieces of tube this long. You now need to cut this amount of tube out of your scrap beam. Consider where you are going to cut; there are castings and bearings in there that you'd be better off not cutting through the middle of. I managed to cut a ten inch length from the beam to take my length to twelve inches. Make sure that you cut square - use a pipe cutter or the jubilee clip trick.
Now you need to assemble the parts of the beam and tack weld them together.
You need two lengths of angle iron and a selection of clamps. Lay out the two ends spaced approximately correctly with the tubes laid in the channel of the angle iron. Then lie the adjusters and the spacer tubes in the channel. Close up all the spaces and clamp everything in position with as many clamps as you have. Make sure that the adjusters are angled correctly. Tack weld everything in a few places. Loosen the clamps on one of the tubes and rotate it to uncover the area behind the tube. Tack weld it there too. Then do the same on the bottom tube.
Then weld up all of the joins with as much penetration as you can manage. If your weld doesn't penetrate to the bottom of the join then you have already started a crack in your weld. Vary where you are welding to keep the beam as straight as possible. Keep the tubes clamped to the angle iron if you want - it will help keep it straight.
You can now cut off the mounting clamps on the front of the beam (which are now too far apart). If you need to re-mount them (buggy or baja) then cut them off carefully and remount them in the correct position - otherwise just grind them off. If mounting on a rail and not using the mounts then you may want to put a couple of bracing bars on instead to increase the stiffness (as in the photo).
Carefully cut off and reposition the steering damper bracket and reweld in the correct position.
Clean up the widened beam (especially the inside) and paint.
You must now cut your leaves. The leaves
must be reinstalled so that they twist the same way that they did originally. Do not underestimate how important this is! After 20-30 years in a car the leaves take on a twist which is imperceptable, until you assemble it wrong and you discover that your car does not sit level. Worse, after they have been twisted the wrong way for a while they will start to fail, and either sag or break.
Also, notice that they are handed - the grubscrew points up on one trailing arm and down in the other - so the dimples drilled in the leaves at the ends (to accept these grubscrews) point in different directions. There is also a dimple drilled in the middle of the leaves for the central grubscrew. It will point the same way as the dimple at one end of the leaf pack and the opposite way to the other.
Lay out the leaves in their correct positions. Make sure that you have it right! Make sure that all the drilled dimples are laid out correctly. Choose two to be the left side and two to be the right side. Cut off the right hand ends of the left ones to the right of the central dimple and vice versa with the right hand ones. You will be left with four short leaf packs with two dimples drilled in each. In two of the packs the dimples will point in the same direction; in th other two they will point in opposite directions.
This probably all sounds terribly confusing, but don't worry - it's obvious what I mean when you look at your beam and look at your leaf pack.
You will probably need to use a cut off wheel in an angle grinder. You can also chamfer the end to make them easier to get into the adjuster.
Clean up the leaves and re-grease.
Install the four half sets of leaves and re-assemble the trailing arms and stub axles. Grease liberally.
