I cant get the spool to undo on my jcb strimmer have tried all combinations of pushing and turning.

Pete Horne, August 2007

If you split the engine from the main strimmer shaft (4 screws) then you can use 13mm socket on T-bar to hold the drive end of flexi drive shaft.You can then undo the square nut at the strimmer head .
Still getting parts seems a real issue, so could try using a cut down socket to reclaim the plastic hex which fails

jcb poor design - common failure, June 2010

The 'captive nut and holder' Parts that I refer to are shown in detail on figure 10 in the MI's
They are referred to as hexagonal section and hexagonal recess.

Slugbabydotcom, May 2008

Further to last:
I did a bit of research and found this http://www.albaplc.com/PDF/IB%20PDF%20files/JCB/Line%20Trimmers/JCB-PLT25.pdf which anyone else reading this should find useful.
I figured that the only way I way going to get into it in my case was to hack the plastic line release button off the end and dig out the spool until I could get a grip of the shaft. Well I couldn't find the cutting bits for the dremel so I just used the "dentist drill' aka large engraver bit. This melted the plastic more than it drilled it. I ripped off the aforementioned parts [Look on page 17 in the MI's] Then managed to grip the shaft below the square nut that was revealed. It came off easily after all that and now I need a complete new end [as per figure 26]
Did I learn anything useful? Er yes as it happens. If you could see the back of the spool holder there is a plastic part which holds the 'captive nut head' which is actually part of the drive shaft and what the line release button is meant to turn against. A pair of mole grips here perhaps with a bit of 'plastic hacking' may help the next victim of the JCB plt25 to get a purchase on the shaft. In my case this captive part of the spool holder was rounded out and the drive shaft nut was spinning inside it.
Heres hoping my experience can save someone else the chew that I have just endured.

Slugbabydotcom, May 2008

With difficulty! I am in the same boat. Problem is that when you manage to turn and push or pull and any part the whole motor turns. Apart from taking the plug out and wedging the piston down which could damage the bore or the piston I can't see any way of locking the drive. The only other plan I have is to take a dremel or small angle grinder to the spool. I am very patient and perseverant at sorting out this sort of thing, but this has been doing my head in since last summer. If anyone else can help it would be appreciated

Slugbabydotcom, May 2008