JK from Zipper's here. We've had a few calls this year (less than 10) of folks who have experienced stud breakage at the backplate, which caused us to look at this part pretty closely. We've been selling this same stud/stanchion setup (thousands!) since early 1999 (same as used with our 8" EV-style filter) with no problems, so if there is an issue with the design, it would have surfaced long ago. However, there could be an issue with a batch of the threaded studs themselves actually being over-heatreated, causing them to be brittle and prematurely break (they are supposed to be of grade 8 strength due to the hex socket on one end would just round out otherwise).
But because any failure is a concern, we tested the same brand steel studs we've been using along with 3 other brands, all claim grade 8 strength. We found that they would all fail (snap!), in a special fixture we used in a press, at about 4 tons of press. Which lead us to believe that the cause of the failed units is isolated, probably an over-heatreated batch of studs.
We have a Rockwell hardness tester here, but the studs are difficult to test due to their size and design, so rather than guess that the heat treat is OK, we looked at different materials and found a stainless steel material that went past 5.5 tons before it spit out the the fixture, deformed but intact (no breakage). For peace of mind, we have since changed to this stainless stud.
At any rate, txbear55 please contact us, or me directly at Zipper's. If anyone else has any problems, please contact us. If you wish to check yours and see something you don't like, contact us for replacement parts.
As always, thanks for using our products. JK