leaking cv boots

hi Sfletch they the axles only spin when you are in four wheel drive or the hubs are locked

Where exactly do they leak?
They shouldn't leak under any circumstances.
If leaking under the end of the boot where the clamps are then the clamps need to be removed the mating surfaces cleaned and new clamps fitted to seal properly.
If they leak at any point on the boot due to cracks, splits or cuts then replace them ASAP or you will be replacing the whole shaft shortly.
If the boot is at the point where it is splitting from age then replacement is necessary asap.
If the boot has a split/cut from an impact from a stick or whatever then they can be temporarily repaired by cleaning the affected area well with acetone to remove all traces of grease and then using Sikaflex to seal the cut. Leave overnight to allow it to cure before driving again. I've done this with success a few times especially when travelling as to disassemble the shafts and replace the boots on the side of the road is nigh on impossible.
I usually put a few pumps of moly grease into the boot before doing temporary repairs to replace that lost as lack of grease will wreck the joint very quickly.
There are split boots available for emergency repairs but they are not a long time solution.
As to why the boots only leak when rotating is that the grease is forced out by centrifugal force.

Hi sfletch. I would suspect you have some small splits in the boot at the hub ends which flex open when on lock. When the hubs are unlocked and not in 4WD the half shafts don't turn. I suspect the turning shaft is agitating the grease and extruding it.

Jack up the wheel and on full lock turn the wheel and look for a split or poor clamping of the boot.

I am sure others will have further suggestions etc.