Oh the joy of Murray spindles. Sometimes they can be rebuilt other times it is simply best to replace the complete spindle as replace bearing ride loose unless you add a little knurling to the housing bearing locations.
Murray had owned Noma so basically was the same manufacture. But now the original Murray manufacture is gone. Briggs and Stratton owns the Murray Rights but they do subcontract out it out to two other manufactures besides themselves. That would be MTD and Husqvarna so the new mowers can be manufactured by either of the three; at least it is noted on the serial number tag. Unlike some buy outs Briggs is still providing many of parts for the older Murray mowers.
But as Gadge said they are consumer grade mowers so they are cheaply made.
As for front wheel bushings depending on the axle and hub size you might be to upgrade those bushings to bearings that ring retainer or flange. Actually a couple styles out now for some of the replacements. But normally those plastic bushing are fairly good but heavy use and heavy loads due wear them out. Much cheaper to replace before they get down to metal to metal contact. Most wear is preventable if the user just grease the axle every once every blue moon or so. You know how well that gets done.
Some owners I think never heard of routine maintenance.
