What's this lovely sound?

[Fastback89]

I keep a spare check valve at all times, This has been an F150 issue for a while

 

[-Ryan-]

My dealer appointment was today and of course they couldn't reproduce. I've been driving around in 4A the last week and I think it's temporarily stopped the problem because I can't reproduce it either now. I'll probably just order and replace the check valve as suggested. Thanks for all the advice.

 

[IHAVETWO]

MINE IS AT DEALER AS WE SPEEK FOR SAME PROBLEM.SAID IT WAS IWE.DONT KNOW YET WHAT THEIR REPLACING.

 

[Kieth]

mine started making that sound every so often. I took it to dealer, and they found not reproduce it. Said it was most likely rocks flying I to break pad area and it stopped when the rock got "sanded" enough to fall out. I get it every now and then, but when I hit the break it grinds then stops and do not hear it again.

 

[g3sys]

Same sound at random on my 18 as well, hubs engage half way and grind.
Didn't waste time with dealer and ordered the redesigned check valve hose FL3Z-3A788-B for $7 plus shipping from tascaparts.com - swapped it in 30 seconds super easy and the issue is 100% resolved.