I had to get a new mandrel housing which goes

Use a wood block to hold the blade back while removing the top bolt. then remove the blade. finally knock the shaft out from the top, should free up with a slight hit on the grease fitting and come out through the bottom. Goes back in the same way.

okay check see if brakes is on the mower, not the tractor but the blades of the mower deck if not then take belt off of the new mandrel side and try turning blade by hand. should turn freely if not mandrel is bad but unlikely. sounds like you changed wrong side mandrel I presume you have 2 blades and mandrels. or when you installed it back on. the belt may be bound up between a guide and pulley just kind of look things over before a tear apart. and then do your tear apart one step at a time then check blade to see if it turns does not seem serious you may have put belt on wrong, I have done it my self. hope this helps major note do not do this with engine running cut you hand off in a flash.

You cannot rule out that the deck has twisted where the blade mandrel sits.

If your blade will secure on the star, just jam the blade with a block of wood and proceed. If you have ruined your star, remove the three bolts that secure the mandrel housing, allowing the pulley to drop down to the deck (this requires some room beneath the deck, so get the whole thing off the ground first) and secure the pulley with heavy wire to the deck. There are a couple holes in the pulley and those bolt holes in the deck. Twist tight. The nut is threaded normally (counter clockwise to remove). A socket with a long handle does the trick after you use a few drops of break free oil.

un hook l/h and r/h lift pins from both lift arms , remove front draft arm from front of deck ( it attaches under the muffler on the chassis )
discoonect the blade engage cable from arm if it uses this type or pop the deck belt off the electric pto if the tractor uses this type

you could just spin each spindle without the blade on ( but leave the top pulleys on ) if spindles bent you should see a wobble , if hard seeing it refit both blades and re-spin each spindle and check for quite a noticable variation in blade tracking when each blade is turned through a rev or two

remove deck , remove both mandrell pulleys from the top of thier shafts
remove both blades and use block of wood and knock the blade spindles out of their mandrells from the pulley side


here is website for parts
http://www.outdoordistributors.com/AYP/AYP_Main.html

just click on 917 the select 288280 from the list
it should show parts breakdown


cheers hope it helps

any problems let me know

paul

Set the thing up on some blocks and try to remove the blade which does not turn. Since your belt is working, the pulley must be spinning or there would briefly be an awful racket. If the pulley is spinning but the blade is not then there is something wrong with the mandrel/spindle, or the blade has come loose and has somehow not cut off anyone's foot. Sometimes the pulley and top of the mandrel become rounded out but again there would be some metal on metal noise. Often there is a star shaped protrusion on the bottom of the mandrel which locks into the blade and by virtue of hitting some immovable object, that unstoppable keeper has been destroyed.

I think that part is called a mandrel, pulley on top and blade on the bottom.
Generally you remove the deck, take off the deck belt, take off the covers, take off the blade, remove the bolts holding the mandrel to the deck. Get a new mandrel at a sears store or small engine repair shop and reassemble in reverse order. May want to do them all while you are at it and save yourself duplication of work next year.

If you have the deck removed from under the tractor you can try putting the blade back on tight if you have removed it and then use the blade to keep the mandrel shaft from turning. It takes quite a bit of torque to break the nut loose on the pulley so a socket and ratchet or breaker bar is the best thing to use. Other than that there is no "special" tool required

Did it break or overheat? There is a small spacer washer that goes under the pulley between the pulley and bearing, if that washer was missing or got ground up on the first one and you didn't notice it the next pulley would rub hard against the top of the mandrel and fail.

Are you sure the spindle is not bent and also are you balancing the blades when sharpening. Other then that make sure bolts are tight on the mandrel. With the deck off and standing up spin the blades and watch center of balde to see if something is bent. Also watch pulley on the other side to see if its bent.