Join Date: Jul 2015
Location: Perth, Australia
Car: MG TF
When I replaced the original knobs with alloy ones on my TF, I found that two of them worked loose quite quickly. I adjusted them until they were a tight-but-not-too-tight fit and then put a drop of threadlok on the grub screw. Has been ok for the six months since. It did take a number of tries to get each grub screw to just the right point.
My reading of the difference between the F Mk1 and the Mk2/TF knobs is that they aren't interchangeable at all, so possibly the solution might be to find a slightly longer grub screw?