#21 is the steering rack. If it is power steering leaking fluid through the boot, then that is what would have to be replaced.

#1 is the inner tie-rod. That is a sealed ball joint that should have grease in there. If the inner tie-rod is really worn out, then that would have to be replaced (~$50 just for the part). The steering rack is ~$250 for a rebuilt part.

If you are seriously thinking about buying this car, I still think you could take the car and get it inspected like Deserthonda and I suggested.

 

Oh yeah, #14 is on passenger side (not #15). Yes, there's just supposed to be air inside that boot. The whole rack (#21) can be replaced or rebuilt.

Here's what's inside. Everything labeled #1 is a "seal kit" so I guess that stuff gets replaced when the rack is rebuilt. One or more of those seals must be leaking to allow PS fluid to get into that air space inside the boot.

 

Wow, thanks for the replies, everyone. I think I'll let this car fall into someone else's hands. Thanks again.