After placing the broomstick in the tube and tightening the cap bolt at the top of the tube, put the shock (rapped in a cloth, a few layers of cardboard or wood blocks) in a vise or use some other means of holding it in place, and  undo the allen-head bolt in the bottom of the shock.  I do this by cutting the "L" off an 6mm allen wrench.  Leave as much length of the straight end as possible, and after placing it in the chuck of an electric (reversible) drill, use FIRM PRESSURE and unscrew the bolt.  FIRM PRESSURE is extremely important in order to keep from striping the allen-head.  (Right) Now you can pull out the retaining clip out of the top of the shock.  If yours has a circlip, get the proper tool at your local auto parts store.

Now the tube will pull out of the shock without any trouble.

The easiest way I've found to remove the seal out of the shock is to soak (1-2min.) the top end of the shock in warmish-hot water and it'll expand the aluminum enough to loosen the seal.

Now that it's all apart, clean and inspect each part for wear and damage.

Be careful with the part circled, it is delicate and it or other parts must not be damaged, bent or scratched.  These are high-performance parts.

Scratches on the inner-top lip where the seal sets are not necessarily a problem,  especially using quality seals shown below.

      I highly recommend a  quality seal with double lips inside and out (arrows).  It's a great advantage, especially in older front ends that are anything less than perfect.

Note:  I've placed this seal upside-down in order to photograph the double lips.

Slide the seal on to the tube from the bottom so not to disturb the "double lips".  Slide it about 12 inches up the tube so it won't get in the way during reassembly.  Slide it all back together carefully and screw in the bottom allen-head bolt.  Put the broom stick back in place and thread the top tube cap bolt, and place the shock back in the vise (as before) and use the drill to tighten.  BE CAREFUL to stop the drill PROMPTLY when it's tight...don't strip that allen-head bolt!  Use presure to keep the allen wrench in the bolt.  The tube may spin, that's fine. 

This piece of PVC plumbing is perfect for knocking in the seal and won't do any damage to it.  The part number is a HomeDepot tag (C4801-2-7) and can be used to find one just like it.  Other wise, it's a 1 1/2 inch adapter of some sort.