Any suggestions on how to removed red dye from a bathing suit
on white vinyl seats?

Im interested in the answer to that too.

My blue canvas cover is bleeding into the white vinyl bolsters. Someone suggested a white rag soaked in bleach layed over the stain.

Okay, I am going to go out on a limb here. I was cleaning the vinyl last night on the Baja. I had noticed that I had left a few toe nail polish scuffs on the vinyl from hurrying around to throw dock lines. I went and got some pre moistened nail polish remover pads at Walgreens. Cutex makes them in little individual packets in a box of like 6 maybe. It took the scuff marks right off. I conditioned the vinyl right after I cleaned it.
You might try that but make sure to condition the vinyl right after. I would ONLY use this on white vinyl too.

I think my problem is more than on the surface. The blue dye from the canvas in stained in the white vinyl, so I think the only thing that may do it is Bleach and conditioner afterwards.

I'm thinking the bleach might yellow the vinyl?

word....Softscrub with bleach ..ok 3 words

You might try Westley's Bleche-White - we used it with pretty good success on our vinyl. Also, when we bought our 280, Powerquest had put a little bottle of vinyl stain remover in the owner's packet. That stuff worked like a miracle! Can't remember the name of it, but I bet someone (maybe Mandy?) at PQ could tell you what it was.... Good luck!

Tryed soft scrub with bleach, no luck.

I've heard softscrub a lot lately for vinyl. I would trust the OSO brethren...

Softscrub is good for that occassional "tough" cleaning (rinse thoroughly!!), but it sounds like he's got a stain. My next choice would be 100% mineral spirits. After that, you may have to contact a vinyl repair place and try to color it white?