A power steering rack and pinion has to be replaced entirely with a new rack and pinion and cannot be repaired with any parts.
So you'll need to pay for an entire new rack and pinion if your current rack and pinion is leaking as it's a sealed unit and is just junk if it's leaking.
A new rack and pinion can cost from $300.00 to $1,500.00 for parts alone and then the labor can cost from $400.00 to $500.00
So the average cost to have a rack and pinion replaced is between $1,523.00 and $1,778.00 for parts and labor for a shop to replace the rack and pinion.
It's a very labor intensive job to replace the rack and pinion so the costs for labor is a good price.
You can replace a rack and pinion yourself cheaper but it's a lot of work and you need to have the proper tools to perform the job correctly.
Sometimes you can buy another good used car for the price of a rack and pinion replacement so sometimes it's not worth the cost of replacing a rack and pinion but sometimes it's worth it.