The tabs on the bolt keepers aren't necessarily weak, but they can only stand bending back and forth so many times. Then they break.
I've got a couple of u-joint ball housings that are so bad that they have lumps on the outside. I tried hammering them back down, but getting the ball back into a true sphere was nearly impossible. Wound up finding a NOS replacement. If the gland nut on the back isn't tight enough, or the seal is worn, crank it down tighter with a strap style wrench.
