6245 clutch/master cylinder problems

The clutch/master cylinder on my 6245 has NO resistance whatsoever. The reservoir is full and the brakes have good pressure, so I'm assuming the clutch/master cylinder is shot.
Is it better to buy a new one or a re-build kit?

Also, while pulling everything apart, I noticed the adjusting nuts on the tie rod at the top of the clutch/slave cylinder were completely backed off.
The repair book makes some obscure reference to this being the "little brake". What exactly is its function? My PTO won't disengage using the hand clutch, so can the mis-adjustment of this tie rod be the cause?

Experts on this site will tell you to replace the master cylinder, however I find it satisfactory to re rubber the cylinder provided you lightly hone it.
The "little brake" is the layshaft brake that stops the gears turning so you can put the tractor in gear without a crunch.

PTO clutch is not affected by the main clutch usually. If it wont stop the PTO turning or is hard to get in gear then try adjusting it as per the instruction book, but make really sure that you have the required free movement on the lever.If the compressor is going then the lever is air assisted and the pto clutch is also operated by the foot clutch when its right down.
Dave