Jetta - Volkswagen :: 2000 - Steering Rack Keeps On Failing - Coolant Leak?

Here are my questions.

1. What can cause repeated steering rack failures, which I am trying to dianose?

2. I found yellow spots in the snow that would come from the center of the vehicle (as opposed to near the wheels), could this be from the coolant system?

If you got that far, here is the relevant history. My wife drives my 2000 Jetta, its a nice car with repeated problems. One such problem is with the steering rack. 1. The steering rack failed in 2006, it was an expensive fix. It was leaking for a while, but I just topped off the fluid every couple of weeks. 2. Within a year the steering rack failed again, it was still under warranty. 3. 2 years later, the rack failed for a third time. I wrangled with the shop and they agreed to reduce my price for the fix even though the part was no longer under warranty. They had the car for a week trying to diagnose the problem, they said they found nothing out of the ordinary. I took the car to another mechanic a week later for some other issue, and he saw leaking from the fill plug--back to the dealer again. They said they cleaned the washers around the plug to fix the problem. No problems since then. Now its almost two years later and I have found a couple yellow spots in the snow, although near the center of the car and not near the wheels. This makes me think it may actually be a coolant leak, but I don't know right now.