How do I change blades on a toro 42 in zero turn

I have found that although they may look similar, with out changing brackets and adding new pulleys they will not interchange. Also decks from the same manufacturer will be different in different years.

Elertric blade drive clutches are a real pain when they go wrong
It sounds like a electrical short is causing the wires inside the switch to heat up beyond the safe melting point thereafter five mins the circuit gets between the fault gets broken as the switch fails the blades stop and the switch melts a bad eaRth corroded may cause this check the deck safety switches are not exposed e.g. they been damaged and the decks metal is shorting them out
a wire has been stripped of protective covering and is touching some metal shorting out something that vital to the blade controls operation the switch is getting a overload and subsequently melting your might need an lawnmower engineer to diagnose to the fault fully and repair

If you were able to jump start mower then the problem lies with the battery connections or battery itself

just had a guy tuesday bring me a zero turn that did the same thing xcept his fell off his trailer ramp and bent one of the blade spindles so now blade digs into cover , engine off blades spin sort of free?

you have burned out the reel bearings replace them and, always keep them lubricated

On mine the arms have to be out the blades have to be off and the parking brake has to be on for it to start hope this helps.

is this all after the parts where changed and while bleeding out the air put the system under vacuum

Sharpen the blades,very sharp,and lift the deck one notch from where you normally cut.Some times the blades will get dinged,or the ends of the blades will dull.

Your blades may be erroded on the edges? Or the center blade hub might be damaged or worn.

good time to inspect all the blades and spindles for wear or damage.

i have the same problem I wish I knew what was doing it I also changed the shaft and still. Could the blade be upside down?