Sometimes, depending on the type of spindles, yes, they have replaceable bearings, usually available at bearing supply houses. Looking at the side of the bearing, on the part surrounding the rollers, should be some numbers which you will need to buy replacement bearings.
That said, if you try to remove the whole spindle housing, be fore-warned: The aluminum castings are very easy to break off the three legs that hold the spindle housing onto the deck! This if you try to remove them to get to the bearings. Thus necessitating complete replacement of the assembly. Not a bad idea, anyway.
You can remove the blade and the top nut and pulley, and try to get the parts out that way. But, the deck may have to be removed to remove the spindle shaft easily. Last ones i bought, about 3 years ago, were around fifty bucks each, which was a complete assembly, less the blade.
Don't know what a vented/ non-vented deck is. Might be an advertising gimmick, designed to entice the uninitiated into buying a certain brand of mower!
HTH: Rusty J.

The vented deck on Craftsman is the spindle setup where they have air passages through the spindle housing to the top of the deck. They made a big deal about how it was a wonderful improvement to the cut as the lift is better because the air could get out more easily. When I talked to a bearing engineer who happened to have worked with them, he told me the air passages were there to cool the bearings better, so that they could use smaller bearings. From what I have seen, about all the vented deck does is put a bunch of clippings on the top of the deck, and into the belts, before they plug and let the bearings get hot.

booster is right. all that vented deck does is suck cut grass into the vent holes, plugging them and in time causing the bearings to overheat.

it could not possibly cost FHP/AYP/roper (or whoever it is now) to design a decent deck to put on those machines.

Sears bearings don't fail too often, strangely enough- at least compared to many others. Even the idlers hardly ever get too noisy. These old 3 legged spindle housings break easy enough tho. If you are getting a shaking type of feeling w/noise, look for burned flat spots on the sides of the belt. If it were me, I would remove the deck, tip it up, push on the idler pulley to release the brake and spin each blade and listen for roughness. If bearings do need replacement, follow Rusty's lead and service the spindle on the deck- as it is likely at least 1 bolt will break if you try and remove the spindle. Leave the blade on to hold the shaft and spin off the top nut w/ a 7/8" socket ccw. The shaft comes through the bottom. The upper bearing will easily drive out the top and if you are lucky, the lower bearing will have stayed in the housing. If not, you can have it pulled from the shaft if you have difficulty with it- or install a shaft kit. Good luck. Don't forget the washer between the pulley and housing on re-assembly!

if you have a broken spindle the first thing you will notice is VERY uneven mowing on the side that is broken. A V shape in the grass.If you need a new one, make sure you get new bolts as You will never get the old ones out with out breaking a couple!

My spindle is broke where the star shape grove is where the blade would sit over. the Star shape is eaten out. so I can not use the blade to counter turn the spindle bolt on top. does anyone know another way to take the bolt off?

Marli2009 - you're new here, so may help you and us if you read the entire thread at the link below:

To your question - either the spindle itself or the spindle assembly should be replacable. But, we really can't direct you direct you without your tractor make/model number info from it's ID Plate (usually located under the tilting seat).

Here is a link that might be useful: New member suggestions

quote
The vented deck on Craftsman is the spindle setup where they have air passages through the spindle housing to the top of the deck. They made a big deal about how it was a wonderful improvement to the cut as the lift is better because the air could get out more easily. When I talked to a bearing engineer who happened to have worked with them, he told me the air passages were there to cool the bearings better, so that they could use smaller bearings. From what I have seen, about all the vented deck does is put a bunch of clippings on the top of the deck, and into the belts, before they plug and let the bearings get hot.

I own a vented deck and bag with the mower exclusively - when the vents plug with debris, the mower doesn't bag as well .. so I believe the vents are there for increased air flow .. they may also lower the operating temp of the bearings, and since the bearings have not failed in 7 yaers venting may increase the bearing life also.

" My spindle is broke where the star shape grove is where the blade would sit over. the Star shape is eaten out. so I can not use the blade to counter turn the spindle bolt on top. does anyone know another way to take the bolt off? "

You have to purchase an air tank / compressor and an
impact wrench. It will remove these kinds of bolts
without really having to hold the blade.