SME V problem

I have a problem with the armrest on my SME V tonearm. It should stay in place but it doesn’t. It has always been a bit loose and has become worse. When I push the arm out of the armrest clamp, the whole armrest swings inwards. This happens also with the base screws tightened. I have to push the armrest back again to maintain the right position. Does anyone know a fix for this problem?
It turns out that the solution is simply to tighten the two base clamp bolts even more. The SME V manual (p 17) says that "excessive tightening" should be avoided, but in my case it has to be very tight indeed to stop the armrest from moving.
Be careful ... The next step after "tight" is "broken" :-)
O holter - this is very odd. I've never had this happen. The arm rest from memory is clamped to the pillar with a cap screw ( just under the arm bearing housing ). If the whole arm is turning ( including both armrest, bearings and pillar etc, then it is the base screws. If it is only the arm rest turning then it has nothing to do with the base screws.
Dover - yes, it is the whole arm, and tightening the base screws helped. Syntax - thanks for the warning. I hope it isn't caused by oil spill (from the damper reservoir). Perhaps I should try to clean the arm.
I had the same problem with my V12 and had to send it back to SME for the proper fix - tightening the base clamp is not the solution as the problem is integral to the arm and cannot be fixed by the user.