The weld on back of the tube cracks and then they leak oil real bad while tilting forward. It cracks right in the center of the weld. The cracks range in size from 1/4" to 1". Some I have carefully re-welded and seem to hold up ok (like the TCM which is ridiculously priced). These are on 3K - 5K triple mast machines. I see this about twice a year but I've done 3 in the past couple of months. I can't figure out if it's from pressure in the cylinder or just stress from the mast trying to pull on that welded-on end pin clevis. I think it is from the drivers running into something with the forks raised some what and that causes a high pressure spike inside the tube.