On the brakes, the rod braking system was a conversion to eliminate the use of brake fluid so as that was one of the biggest headaches on some Crystals, to not have the bother of losing you brakes if the slave cylinder went or one side way stronger than the other or visa versa the next day or seals going on the master cylinder and losing all your fluid on the ground or having to be bleeding the air out constantly, the rod system must have been a godsend.
But it won't improve your stopping power if the brake parts are worn internally.
Nearly all Zetors had a compressor on them only maybe some in the 80's were missing them but all the 90's and right up to the newer ones do, even my HSX has one very useful for pumping tyres, got a flat on 6 reel hay turner last summer, I was 10 miles from any garage only for my Zetors compressor would had been in trouble. If your pulley is loose it will need new bearings.
If the PTO is spinning continuously, that is a classic signs that the torque pump is gone. Because when it goes the PTO can't be stopped and the tractor is stuck in LO.