I found a much cheaper and much more effective way to pull swollen glow plugs. Go to the hardware store and buy a metric nut (10mm x 1mm). You'll also need a pair of vice grips and a hacksaw if you don't already own them. Clamp the nut to a flat surface and cut it in half with the hacksaw. Then, after backing the glow plug out as far as it will come, take the 2 nut halfs and clamp them to the exposed threads of the plug with the vice grips. Now just back the glow plug out the rest of the way. It works like a charm and it's cheap!

I think that the general consensus from those that have done this with swollen tips before is to take out the injector, stuff up the precombustion chamber outlet port with some kind of cloth that you can pull out in one piece with a pair of pliers (make absolutely certain that cloth is 100% cotton, not a synthetic), break the tip off the glow plug, allowing it to fall onto the cloth, fish out the broken piece (some say a magnet works ok), vacum up any small pieces with a piece of tygon attached to a vacum cleaner hose and then pull out the cloth once you are sure there are no pieces on it.

The extraction tools will allow you to get a plug out that has frozen threads but it won't prevent the swollen piece from dropping bits and pieces as it gets pulled out.

A diesel mechanic that I know said to me ALWAYS use plenty of penetrating oil A FEW days in a row BEFORE trying the get the glow plugs out. He said it works every time.

David