Heel tension issues

Based on the reviews I read on this site, I recently bought a pair of HH bindings, and so far have been very disappointed. Help me!

Specifically, I'm having problems with keeping tension on the heel of the boot - I can tighten the hand screws on the rear C-loop as tight as possible while still getting the heel throw up, but as soon as I engage the binding, the heel becomes loose again. The C-loop isn't stripped (the threads are in the same position), it's almost as if the front spring isn't 'springing' back to where it should. As a result, I'm stepping out of the bindings 2-3 times per run, even tightening the hand screws as tight as they'll go. Any suggestions?

I'm skiing in the "4" position and have a large boot - 29.5. Thanks!

It seems these need to be broken in. I think the new cables stretch a bit. I had an issue with mine gradually loosening during my first few days out on them. I would tighten them up, ski a few runs, and then check the tension. Solution: Leave your boots clipped in to your bindings for a day or so. Check the tension at your convenience. This should quickly "break in" your bindings.

Oh yeah, one more thing: make sure when you spin the springs for tightening that they are actually going INTO the rear hoop, not backing out, which will give you WAY too much slack. BTW, I have been able to fine tune the tension on mine so that the bindings will actually release if I take a nasty fall, yet hold fast for some serious ripping. One last thing: We all assume that you're skiing with standard 75mm tele boots, and not the new NTN or AT boots. Right?

Keep it in mind that there is a left binding and a right binding, which is notable by the small ring hole for the leash to attach to the corresponding leash ring on each boot. That means make sure that hole is on the right side of the ski for the right foot and the left side for the left foot. If you've got that 1st part straight, then confirm that when you flip the heel bale lever up to engage your heel, it goes under firm tension. If it doesn't take some effort, then you'll need to spin the springs to tighten things up. If the springs are spun as tight as you can get them, then you'll need to shorten the cable travel, and if my memory is correct, that adjustment is made under the forefoot plate. If all that still offers no joy, then take in to your dealer for proper service.