Relative to glide lock system:
Yes there is a spring below the pusher. 1 piece of sheet metal screwed down in the clasp and with lifted ends on each side. Kind of blade spring, very basic.
I have opened the clasp (4 screws, use appropriate driver to avoid damaging the screws); relatively easy, just remember how it is assembled to be able to reassemble correctly.
Cleaned everything; was pretty greasy and dirty.
Then have slightly lifted spring located below pusher; be careful not to exagerate and risk braking it.
This was OK to raise pusher and have nice push action but not sufficient to have tight assembly as there was too much play between slider and clasp.
I did not want to ply spring trip much so
I added 2 stripes of thick plastic tape under the slider.
Kind of transparent Scotch tape but much thicker.
Now play is reduced and locking system works.
I have not added lubricant for now because lubricant fixes dirt.
Hope explanation was clear enough.
Interested in other solutions tested by you guys.
Can take pictures this WE.
Avanti76