How long does it take to replace a clutch disk in a 1989 corolla?

4 - 6 hoursdepends on who is doing the job, if its a pro, i'd allow 4 - 6 hours.

i wouldn't only replace the clutch plate, if your in there, you should also do the pressure plate & thrust bearing also, better to do them now, than have all that work done again in a short time.