try some boiling water over the 13m section to get it to expand a fraction followed by a sharp tap on the floor if that makes sense, I have managed to get mine out by sliding 2 fingers up inside the 11.5m section and then flexing my fingers so that they lock against the inside and then pull.There mite be some damp in between the 2 sections which is creating a vacuum effect, try leaving the sections out in the sun, and then try the sharp tap on the floor again.

M8 don’t put any liquid or ur pole or on the ground !!! U need three lads 1 in the middle where the sections r stuck and 2 on either end ! The 2 on either end hold pole firmly while the lad in the middle holds the stuck joints and rotates like ur rowin a boat its stuck bcoz ur section was wet and the trapped air has caused a vaccum ! This is the only way u will seperate the joints ! Remember hold firmly either end an roll the middle section u may need to use quite hard force bt it will part after 5 to 10 mins of rollin ya joint ! Hope this helps , nick 🙂

Nickyboy, you have misunderstood the question.

Assume its a Garbo ??

I have had this same problem before, tried water, tapping, fingers, radiator and all manner of other suggestions.

Mine was stuck due to bits of Grit !!

The way I finally got the sections free was to use the half extension that fits up the 9 and 11m sections, place this inside the male end of the 13m section so it sits flush to the male end of the 11m section inside and tap it gently to force the 11m section free. You wont damage the half ex but you need to take care not to damage the 11m section, this was the only way I could free it but it worked with no damage to anything.

If Sliders tips do not work someone on here once suggested using an expanderbung. The sort you can buy that screw adjust to fit any end section. Simply put it inside the smaller section and expand it just enough to grip the inside wall without over expanding it otherwise you will only jam things up more!!
Hope it makes sense.