Tighten the 2 screws underneath with the lever in UNLOCKED position. Make sure you tighten the 2 screws very tight. After this, if you may find you no longer can lock the lever, then you just need to loosen the adjustment screw (the one inside the black cap on the side) until it is just right to lock the lever.
I had tried the approach you suggest, (ie: tighten 2 screws with lever in unlocked position) then adjusting the internal screw. Trouble with this is I was not able to then move the base clamp. It just became permanently stuck...... but I'll give it another crack and see how we go....
If it became permanently stuck, that means you need to loosen up the adjustment screw even more. So, loosen up the adjustment screw until the bases will slide freely even if the 2 screws at the bottom are tightened up very well with the lever in the UNLOCKED position. Then adjust the adjustment screw until the locking mechanism works well.
Hey Icewater888, tried your suggestion and once I tighten the two bottom bolts as tight as possible with the lever in the UNLOCKED position, there is no way I can loosen the adjustment screw to allow the whole clamp to move freely on the slider......... Its interesting that your suggestion is similar to what the instructions suggest, however seems like there is something lost in translation of the instruction manual.... the way it reads, looks like its a poor Chinese to English translation
Once you have tightened the bottom screws, does the adjustment screw turns either clockwise or anticlockwise? If it doesn't turn at all, then I would loosen the bottom screw, then loosen the adjustment screw even more then retighten the bottom screw. EDIT: the adjustment screw should still turn even after the bottom screws are tightened. If not, then loosen the adjustment screw more (before tightening the bottom screw) and try again
I had this issue as well with one of my rails (but not the other, weirdly), and for me it was easy and cheap to solve. You might need to add some space between the base cones and the bottom blocks - you can do this with some Form B M6 stainless washers: You can try one pair and see if that lets the base move, and if it doesn't, add another pair, and so on. I only needed one pair - 0.8 measly milimeters - to go from "will not move" to "works perfectly". Also, there comes a point when you are loosening the adjustment screw at which the crew itself will begin to poke out of the cam follower and foul on the internals, so be careful of that.
Thanks guys for all the suggestions. Solved it in a slightly different way. The problem was that after setting it up as per the adjustments suggested, you always find that with the lever in the open position to slide and move the base around that the two bolts will always be loose. With moving and rattling, those two bolts shake looser and eventually require more adjustment which was the problem I was having. So I went out and got some non setting, non hardening, high viscosity pliable sealant and put it on the thread of the bolt before inserting it. That way, once I make the appropriate adjustments as per all your recommendations, the two bolts are held in their positions by this high viscosity putty like stuff and does not shake or rattle loose.
