By Alan Klingen and Gerry McCarthy
Alan Klingen: The split boot will seal very well when installed correctly and the right boot is used. To put on the solid boot correctly you really need to take apart the axle tube.
I like the FEBI brand split boots from Germany, as the fit and the hardware is right. The most common error I see at the shop is the sealing of the halves at the clamp. You must position the clamp so that the action of both halves of the clamp coming together also draws the open seam together. Get as closed as possible by hand and the clamp will do the rest. No need for any sealant when done correctly.
Screw together the split first being careful not to tighten the bolts so much that the seam opens up again. I would guess the washers sink into the rubber about 1 mm on each side.
You want to position the seam at 10 or 2 o'clock. If possible get the axle level but don't if the method you use is getting the car off it's jack stands. Place the clamp for the big end first. You want the clamp to "draw" together the sides of the seams so place the clamp so at its joint that are sliding together are on each side of the seam. Push together the sides as much as you can by hand and then tighten the clamp.
You should have some good lube on the tranny flange like some oil, and you will see that the seam will close as the clamp is tightened. Do the same for the small end. You might need to push the small end a bit toward the tranny to get the bellows neutral. Check the bellows when the car is back on the ground that they don't over push the bellows so that they fold on top of themselves. If done correctly no sealant is needed.
Gerry McCarthy: Solid axle boots are the way to go! First, they don't leak, second, they look so much better! Wolfgang Reitzl showed me the correct proceedure 53 years ago. First, deburr and slightly radius the edge of the bell with a fine file. Clamp the shock mount in a vise tightly, because you are going to do some serious prying on the boot. Turn the boot inside out!
Apply Dow 111 or other white silicone grease to bell and boot. Pull the large end over the bell as far as possible, then, using a 3/8 or so dia. rod, rounded on the end, strech the small end over the bell (I use a long shank #3 philips screw driver)
Be careful not to pinch the boot! It will go over with much less effort than you might expect, if you get it right. Pull the boot through the mounting flange, then turn it right-side out. (that can be harder than pulling the boot over the bell) Tighten the clamps with the tube square to the flange, and put about 10MM preload on the bellows. (push the outer end toward the flange).
I have done this on 60-80 cars,at a guess, and tore only 1 boot. I also punched a hole in a couple, by pinching it with the bar.
If you must use the ugly (but efective) split boot, I was taught to place the seam horizontal, so that it bends, not streches, as the axle swings.
Removing and installing the bearing housing is no picnic, by the way. You must have a proper mandrel to push on the tube, because it takes several tons to move. Be sure to remove the 3-groove pin! If you do not align the pin hole perfectly with the notch in the tube, when you drive the pin back in, you cause a small dent inside the tube, which will not clear the bearing flange on the axle, so, you can't install it. You may also, during pressing apart, create scratches in the tube, which will leak like a fire-hose on reassembly. I hope this is of help, and does not scare you off from doing it right!