It is really important to clean as absolutely clean as possible all of the power steering components, particularly the tube, rack and ends with the seals. Any dirt can cause friction and wear on the rubber seals and premature wear. One reason the passenger side seal goes fast is that it is right on the outside end of the tube near the tie rod. Any dirt or sand that gets past the rubber gaiter and onto that steering shaft can cause wear and seal failure. That is why it is CRITICAL to have the gaiters in good shape and sealed tightly at both ends.
If there is any roughness on the rack where it passes through seals it will also cause wear of the seals. It is not a bad idea to very gently polish the rack with SUPER fine sanding paper or a polish. If you see there is corrosion and pitting on the rack – you need a new one.
You also need to make sure the seals on the rack tube are in the correct orientation. They are concave on one side and the concave sides of the O-ring seals should face inwards to the rack. If you put them in backwards they will not work.
I also found that in the seal kit I bought the large o-ring that seals the coupling between the two halves of the tube was flat and not as deep as the o-ring seal I removed. Sure enough, it did not work and had to be replaced with a proper seal. Take a look at the pictures below. I found the large o-ring that was rounded and thick worked, while the thinner flat one did not. I got the correct one from Coventry West – Much thanks Dick!
A final point is to be super careful inserting the seals into the groves and then running the rack through them. The serrated edges on the driver side of the rack can rip the delicate rubber seals and you can have immediate failure once you put the fluid under pressure. Take your time, be super careful and use lots of rubber friendly lubricant to make sure that friction is at a minimum. This is important on the large o-ring seal between the tube halves and also super important when re-inserting steel sleeve that holds the seal in the driver side of the tube. It has to be pushed a long way down the tube, and you have to make sure that at the end it lines up with the hose coupling that screws in and holds it in place. Having the tube and sleeve lubricated protects the two seals from friction and makes it easier to slightly adjust the sleeve so you can screw in the coupling.