Brake line routing and clearance?

[tery]

Hi, So I see that poem brake line installation runs the lines right up next to the frame, it looks tidy and safer for when you are crashing through the bush and don't want a line to get caught on a branch or something...But it also holds the lines nice a tight up close to the frame so water can sit there between the line and the frame and take out the line as quickly as possible. I have done one car's lines to the rear and a shop...the pro's did another one two years ago when I was afraid to try it myself...but the ones I did seem fine and I didn't bend things so that they were married to the frame and body, just tucked them up and of out range..
Two questions here...do brake lines get hot enough to melt a substantial zip tie...if so I'll use aluminum wire maybe and then when the rear lines leave the proportioning block on their way up too the front, how much clearance would you say I should be sure to have between the bars that go out from the center to each wheel and the brake lines... Look at this pic and see if you think I am safe there. I jacked up the wheel and it seems like there is plenty of room there, like the wheel would have to go up into the top of the wheel well and scrape the top to get any closer to the brake line I think.... Seems like the coil spring would keep that from ever happening too.. Thoughts please when you have them to share. Take Care,
Terry