After a few months of owning my '98 C70 I started experiencing a squeaking noise whenever I turned the wheel. It is worse when the weather is cold and I found a great guide on how to fix this:
http://volvospeed.com/Repair/70steering.php

I have located, removed, cleaning and regreased the nylon bush and the noise is gone great!
...but after a few months the noise returns without fail and I have to go through this procedure again and again.

I am wondering what am I doing wrong; I clean the nylon bush so it looks like new in spirit, clean the inside of the boot, and regrease everything with Castrol grease and have also tried other grease.

The steering boot, nylon bush and steering column are the three components along with grease that is causing this problem. My only conclusion is that there is some special grease or that the rubber boot is out of shape or damaged, although upon inspection it seems fine.

Anyone have the same experience or could provide an insight.

Alex