New Flexi tails leaking on monobloc tsp

[Boaster38]

Hi I have a monobloc mixer tap which is 18mths old. a leak appeared underneath in the cupboard which looked to be coming from the flexi tail M8 end I replaced the new tails but when connecting up (hand tight)the leak is worse, is this a tail issue or could it be a cartridge perhaps, I have used ppte tape which improved it but still leaks

 

[Ben-gee]

Not cartridge if it’s leaking from there.
Were the o-rings in place and in good condition on your tails?
Better tails have two o-rings and these seem to more reliable.
However even with no o-ring you should be able to get it leak free using ptfe.

 

[Robooo]

Pictures would be helpful.
The first instance could be condensation perhaps.
PTFE maybe used in some situations but many times applied incorrectly. May you can get a better sealing compound?