I made a rover for drilling, containing both wheels and landing struts (for support while drilling.) At first it worked fine, but as I was playing around with various wheels and configurations, I noticed during testing on Kerbin that one or two of my landing struts were breaking right as they were being extended. I put the old wheel configuration back on, but now the struts are still breaking when I expand them. I don't think it's the wheels, but I could be wrong. Sometimes it's the two front struts that break, sometimes it's just one (and not always the same one) even with no changes to the rover. Any thoughts on what might be causing this?
In this case, it's the leftmost strut in the picture (the front left one) that's broken. My engineer could repair it if he was level 3, but who knows if it would happen again, and on Minmus too…
Again I want to stress that I had several successful tests in the same area on Kerbin without any major changes. The only thing I added was some structural struts over the batteries (they were shifting a bit on bumps) and messing around with the wheels as I said before.
Best Answer
99% chance to fix broken landing legs
Given that the rear of your rover is in the air, the problem is probably that you were moving when you deployed your landing legs. Apply the brakes and stop before you lower your landing legs.
To apply brakes:
If that didn't work...
If that didn't work there is a good chance your landing legs are "clipping". That is, they move through another part resulting in weird physics and broken vessels. Try moving them out of the way of the other parts (it looks like they're very close to your solar panels).
If that didn't work...
If that still didn't work, there is one sure fix for every KSP problem - MOAR STRUTS*
Try running struts from the hull to the fixed part of the landing legs.