Hi Grant,
Our company IJES.ca has trained our technicians with Sachtler, Vinten, OConnor, Miller and Cartoni at their facilities in Italy and the US. We specialise in the repair of Camera suport equipment of all makes.
In answer to your question regarding the adjustment of the lower leg lock on your eng2cf tripod. The 4 screws you see on the opposite side of the lock lever are the adjusting screws.
Just don't be tempted to overtighten them and make sure you adjust them to an even torque. All you want is enough to hold your payload basically. the screws will strip in the plastic if they are overtightened or you may break the bracket.
Please also check that none of the brackets are cracked and that the tubes are firmly bonded into their respective positions, you may see a line just above the bond line, this indicates that the leg has come loose.
I am afraid that Sachtler does not produce repair manuals, just "explosion drawings" and I see that you have one now.
I hope this helps.
Best regards, Ian.