GMT-800 Give this a quick check...

[Miatch]

While driving down the highway, I suddenly had a very uncomfortable feeling. My track bar (panhard) broke away from the axle housing.
Not a huge deal while on the road, but if I were off road when it broke, I imagine, the control arms wouldn't last very long and that would be catastrophic.
Upon inspection I found that of the five or so points that it is welded to the housing, only one was shiny. This means that all the other points had been broken for quite a while and I have been driving around with one small weld holding my track bar on. If I had done better inspections, I would have found this out before it broke.
So my advice, drop down there and inspect your track bar welds. I bet a lot of yours have already have started to fail.

 

[Ramblejam]

I bet a lot of yours have already have started to fail.

Was this failure on the 1500 Suburban running 35's with a 7" lift and air bags?

 

[Martinjmpr]

Was this failure on the 1500 Suburban running 35's with a 7" lift and air bags?

Good observation. That lift puts a lot of stress on the stock components. For that matter, with 7" of lift would think you'd need a longer panhard bar.

 

[HenryJ]

The panard bar also needs to be horizontal so that it rides at the apex of the travel arc. This means extending the mount and creates a situation where, if not properly reinforced, the increased leverage can also cause failure.
I reinforced and repaired the broken mount on a friends Avalanche. His had a 6" lift.

 

[Burb One]

I just upgraded my panhard bar to an adjustable Spohn, out of worry the stock stamped steel was weak. When replacing, I must say I was thinking the mounts look a bit weak, however theoretically the panhard bar shouldn't bear much weight more than the axle.

I think lift, weight and 35's coupled with, as said earlier, a too short panhard bar, when in compression and droop on one hand, troques the bar pretty hard. I'd look that the bar angle when at rest, and also compression. Id also say it's too short. I know when I replaced mine, I found my new one to properly be set longer, and that's with me being mild on my lift and with the panhard riser mounts on the axle side from the lift kit.

Also how do your lower control arms look? One of my friends tahoes on 35's and lift, folded a stock control arm while off road.... A flexy control arm could torque the bar (and mounts) as well...

 

[Miatch]

My control arms look good but my Suburban has really only been on light trails and only a couple times. The previous owner kept this as more of a show truck.
I believe the track bar mounts are the weakest point. I am sure the bar could be a 1/2" longer. I haven't really considered the stress that might be creating. It would be easy enough to calculate the proper length and replace the arm and flatten out the mounting.
The best way would be to weld up some new bosses and make a bar with some nice heim joints to get it perfect...but I can honestly say that I will never get around to it.