I recently posted a problem with the auto park system on my P30 motorhome. I want to thank all those that responded. I believe we finally solved he problem. It took a while to realize the brake was working just fine. The problem was it was not fully releasing.
By watching the cables work I was able to see that one of them did not fully return to the start position. For some unknown reason the brake would remain partially applied, just enough to 'cook' the shoes in about 1000 miles.
The shoe return spring was replaced and a clamp was placed on the cable so it had to return to the fully off position. This was a very difficult thing to see as the cable would release BUT not 100%.
Maybe this will help some one else. This is a good parking brake system when it works but this condition cost me four set of shoes in one year because none of the mechanics spotted the problem. Ed