2011 sedan. Ran over some debris on the highway and crawled under to see if everything survived. On the passenger side there are four tubes of two different sizes running the length of the frame and one of them was nicked up. Assume these are brake lines. Anyone have experience replacing them? Are they available pre-bent? Why are there four? Been searching different part sites but can't tell which of the tubes they are referencing

 

They are not all brake lines. You have two (2) brake lines, one (1) EVAP line, and one (1) fuel supply line:

Typically, these are hardened steel lines. Unless they are bent/ kinked, collapsed, leaking, or otherwise compromised, I would leave them alone. I do not see anything in your picture that shows cause for concern. What concerns you?

But, for the record, yes, pre-formed replacements should be available from Infiniti.

 

Red circle shows cut in the line. Gonna have to lift the car to get a better look. Thanks for the diagram. Where did you find it? I looked everywhere I could think of without anything close to this. If I read it correctly,the evap line is the issue not the brakes. Is that fuel evaporation?

 

Found the diagram online. I was looking for brake piping, didn't think to look for fuel piping. Thanks again

 

That does appear to be the EVAP line, however, you would have to physically trace the line from front to back to know for 100% certainty. The EVAP line carries fuel vapors from the charcoal canister in the rear bumper area to the engine intake. It is all for emissions nonsense.

Again, typically these are PVF coated hardened steel lines. It takes a lot to damage them to the point of needing replacement. It is hard to determine in the picture if any reason for concern exists. Perhaps after you put the car on the lift you can gain a better perspective. If you can, please take a close up picture and post it up.

Does your car exhibit any symptoms?