I have a 2001 ex. 4x4 6.8 v10. I have been having vacuum issues and brake issues lately. My front brakes seem to be sticking, some times they drag some times the don't squeeze when I step on the brake causing uneven wear and pulling when I stop. Also feels like I have no power assist. I also have a vacuum issue with the auto setting on the hubs, they don't engage I have to manually lock them and sometimes my a/c stays on defrost. And my cruise control doesn't work, the light comes on and love done the self check but it doesn't show anything is wrong. Could I have a bad brake booster?

 

It sounds like you have multiple issues. What you will typically see with a bad brake booster is an extremely hard to press pedal with very little braking power. What it sounds like is you have sticking calipers or caliper slide pins which will be fairly easy to diagnose. The issue with the hubs is most likely the vacuum lines going to the hubs. If there is a leak the HVAC will default to defrost mode. I'd test for vacuum leaks - with the engine running lightly spray intake cleaner on any vacuum lines you see and see if the RPM's change at all.

 

Lots of issues there but it sounds like a sticking caliper pin especially when the brakes don't wear evenly.

 

Well I found part of my problem...I blew a brake line yesterday and now that the new one is in my brakes work so much better than they have been so I must have had a pin hole in the line for a while but it still feels like I have no power assist

 

Check the 4X4 vacume switch on the RF inner fender. I have the same issue with the A/C. someone mentioned to me that the switch will rust and split creating a vacume leak, that is exactly what happened to mine.

 

A leak there might cause problems with the blend door and 4x4, but not the booster. The OP has a BIG leak.

Mike