10" LX90 Declination knob on a fork mount fix

Hi I recently acquired a 10" LX90 on a fork mount. I said DEC knob in title but meant the AZ knob. My issue is when I tighten the AZ knob really tight the OTA can still move if bumped. It holds but not super tight. Is this a common issue? I added the Peterson EZ clutch and it helped a little but not enough. I previously owned an 8" LX200 and when you tighten that knob it is completely locked into place properly. I just ordered the balance weight kit because I am concerned that when I start using heavy accessories the OTA will move. But even bumping it can knock the scope a little out of align and I don't want to have to re- align every time I accidentally move it. Does anyone have a good fix for this? Any help would be appreciated. Thanks

This issue seems to be ok now. I locked the OTA on the vertical position and moved it up and heard a click. And now when ever I go to tighten the knob the OTA actually locks in place. Not sure what changed but it seems to be working.