Product review (2 stars): Works, but some kits may have an incorrect retainer
My kit arrived and I was in the same boat as 2 other reviewers - it did not include one of the correct parts. This kit 285809 is supposed to include a short cam, 4 dogs, and a retainer (I have also seen the retainer sometimes referred to as a bearing). When received, the cam and dogs were a perfect match for what I had. The new retainer was a natural nylon color (my old one was yellow, and looking online at images for kit 285809 show a yellow retainer as well). This new retainer is clearly not designed for the cam included, and would not fit at all without deforming the part.

I was able to use the cam and dogs, and just re-used the retainer I already had. The reality is that in many cases (including mine) only the dogs are worn out and need replacement. Everything went back together and works fine; but if you know you need the retainer be aware you may not get the right one - it looks like some kits have been put together with the incorrect retainer.  Other reviewers report no problems so I'll bet some kits have all the right parts and some do not. Luck of the draw!