Problem with VPI 16.5

I'm wondering if anyone has had a problem with the suction tubes on their VPI 16.5 cracking and breaking. I've had my unit for almost 2 years. I went through the supplied tube and two more I bought. They all started to show stress fractures where the tube is inserted into the swivel holder, that goes into the "inside of the unit". I did contact VPI, sent them the broken tubes. They replaced them free and I was told the problem was in the height adjustment of the tube on the "swivel". There is a collar with a set screw allowing adjustment for the height of the suction tube above the lp on the platter. I was told to experiment with different heights. I have moved the collar a little each way and have so far succeeded in breaking two of the three free tubes VPI sent me. In the past I have used crazy glue to repair the tubes, and that works for a while. It looks like I may have to contact VPI again, maybe send my whole unit in to have them check it out. I have no complaints about the unit otherwise, I just can't seem to get the right setting, and the way it came from the factory wasn't working. I must say that the vacuum seems quite strong and there is definitely a stress point where the tube fits into the swivel. All the leverage of the vacuum and the tube contact with the moving platter, is centered at that point. It is a weak spot, IMHO. At one point I thought I had discovered the problem. With the more recent units, the clear plasic lid is inset, below the top of the box, and it can press down on the tube at the end, especially when the tube is turned toward the rear(the position it would normally be in when removing a record). I tried only closing the lid when the tube was fully into the center of the platter, with the lid only making contact with the swivel part. This did not change the cracking and breaking. I'm not sure how many records I've cleaned, maybe several hundred since I got the machine. I'm not cleaning scores of records weekly. Would appreciate any suggestions and would like to know if anyone else has had this problem. thanks!