I have had some luck using a lot of JB Weld if the crack is not too large. Place it underneath so as not to show. See if your unit has a step stay kit installed, this is a gray metal brackets on each side under the floor. this along with a new "improved" fender was supposed to correct the cracking. My BX24 is 2006 & you will notice you need to be careful because over time the plastic becomes more brittle.
As for the ball joints unless they are severely worn, replacement is not necessary, usually the rubber boots crack or get torn.
This is a copy from a previous post on another forum about protecting boots.
Default Re: BX Tie-Rod boot ripped
What I did for my BX24 when the boots got torn from brush, was I ordered two universal tie rod boots part #40193, also uses Massey part# 1885486M1. These boots sell for about $3 to $4 at most tractor supplies, online, & EBAY. TSC has these boots in a kit, but you have to buy 6 boots, 4 of which are not compatible & the kit is $20. Note these boots are not an exact replacement but the difference is so slight it is hard to see. They fit my BX24 perfectly & I was able to reuse the original metal retaining rings. Then so as not to have to do this again I used TECHMAN's idea of using a piece of 2 1/2in. nylon hydraulic hose covering held on with tie wraps to cover the boots. The nylon cover material can be purchased at any hydraulic hose place by the foot. Mine was about $8 for a 1 ft. piece. I used a heat gun to seal the ends to stop fraying & a soldering iron to punch holes for the tie wraps.
