Leaking Bilstein 5100 shocks

My original factory Bilsteins simply lost their rebound damping (no visible leaks), but two other sets of 5100s started leaking in winter. I live in the Southeast and my truck is always garaged (except when at work), so it’s not exposed to severely harsh winters. Bilstein is the only brand of shock I’ve ever had leak.

 

My 5100s leaked after 60k miles.

 

70,000 on mine with a lot of offroad miles. No issues.

 

I just had my 5100s replaced. 12 years old, 80K on them. Normal tacoma usage with light occasional off-roading on weekends. One of the fronts had a small leak, under the rub cap, that I never saw until they were removed. As you can see the rubber mounting grommets are completely shot and dried out on the rears. I believe the washer was making contact and producing bell ringing noise. This stopped after the new ones were installed.
While they are all still functioning/rebounding after removing, my ride is noticeable smoother/better. Several people commented without being told I had new shocks.
I would say it is is a good idea to replace shocks at 60k-70k as many say, even if others claim Bilsteins last 100K+

 

I accidentally turned my 5100 rear shock while tightening the top nut. I didn’t realize it was turning. I would say about 10 turns. Did I ruin my brand new shock?

 

Not at all. Perfectly fine. That's just how pistons work.