How do I replace the mandrel shaft on my mower deck?

Wade_ EXPERT July 01, 2009

You'll need to block the blade to keep the shaft from turning. You can use a block of wood for best results. Then unscrew the nut on top of the mandrel pulley. The pulley will then lift off. If there is a washer under the pulley, make sure you hold onto it. Next, take a hammer and knock the shaft out of the mandrel housing. Since you're replacing the shaft, it won't matter if you damage the threads on it. When the shaft comes out, the lower bearings should come out with it. If they don't, you'll need to use a hammer and punch to knock them out from the top. Since you're replacing the shaft and it comes with the lower bearings, I recommend replacing the upper bearings as well. Take the hammer and punch and knock the upper bearings out from the bottom side.

Then put everything back in in reverse.

I make it sound pretty easy and it really is a pretty easy job. The hardest part is getting the mandrel pulley nut off the shaft and that's not so bad if the have the blade blocked to keep the shaft from turning. If you cannot block the blade to keep the shaft from turning you will be in for a long fight. Unless you have an air/electric impact wrench.