Stcky NSF Brake Caliper

Help!!
I've tried searching, but to no avail....

The NSF caliper has started to stick on my 02 TD4 Gaylander. Sliders are OK, and greased up (looklike new) piston lovely clean and shiny. Replaced dust cover on piston and when I unbolt caliper, push ****pot back in and get someone to press pedal you can see the piston move out, then withdraw slightly as normal. Couple of days later, brake sticks again. AAAAAARRRRGGHHHH!!!

Any ideas?

Using the thin extension tube attached to a spray can of 3 in 1 oil gently insert between the dust seal and the piston and spray some oil in and then remove trapping the lubricant inside the dust cover .
Some will say never to use oil as it will attack and perish seals but I've been doing this for years on many vehicles without problems.

Cheers for that steely, but already tried it. It doesnt seem as though anything is sticking at all when I take the caliper off and try it, and for a few days its fine, then it sticks on.
Might just bite the bullet and replace the caliper, already spent over half the cost of a new one on replacing bits of the old one....

You might consider changing the flexihose at the caliper . I've never experienced it but I've read of hoses degrading internally resulting in a " flap " being created which acts like a non return valve allowing fluid to flow but not return thus causing the piston to stick.
Long shot, but somethings causing it........

I've never experienced it but I've read of hoses degrading internally

Happened to my son,s Transit about a month ago, Had us foxed for a time.

Thanks for the advice fellas. Ill post on here what finally fixes the problem.....

If anything does.......

Simple fix....replaced the pistons and seals in both calipers, and hey presto sorted.
Main stealer stated that I could only replace caliper as unit and couldnt be stripped and rebuilt- hundreds and hundreds of my hard earned cash he wanted.
Pistons were £10 each, seals came with pistons. Much better......