How can I un-bolt the Mandrel Pulley from the shaft?

cut it off with a hand grinder with a cut off disc

pulley running on housing or faulty bearings
if one housing bearing failed , good chance that the other side will not be far behind

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.

Order part no. 128774. My poulan mower takes the same mandrel as your.

impact gun is the easiest way, if not the you will need to use a pipe wrench and a ratchet. Hope this helped Tim

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.

since the parts illustration doesn't show a woodruff key, i would guess that the input shaft of the transaxle has a flat area that matches up to a flat on the pulley - if it's just spinning, that would mean either the flat has been worn out, the center of the pulley has broken the weld, or the transaxle has something broken internally - the pulley is held on with a snap ring and thrust washer, remove those and the pulley should slide off the shaft - pulley part no. is 184787

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.

there are thousands of these mowers out there, and most people do not have the problem that you are experiencing - let's face reality, you are hitting something, that's the only way these break - it is impractical to make a machine that will mow through rocks, stumps, and water pipes and not break - also, sears does not MAKE anything, they contract companies to make products for them - if you want a thicker, tougher mandrel housing, log onto www.amcpartsstore.com. they recently began offering a heavy duty version of the mandrel housing, part no. 130794. i've seen these and they are definitely beefy - just be sure to put everything together correctly and tighten all the nuts and bolts firmly, and try to avoid the rocks and stumps

You have to remove the nut on top of the pulley. With the pulley off, the shaft will slide out the bottom with the blade. Don't forget when you put the pulley back on, the washer/spacer goes BETWEEN the pully and housing, NOT on top of the pulley. Dwain