I just finished a timing job on my '06 5.4L f150. I went to back the truck out of garage when I was done with job and brakes didn't work. Worked fine before timing job. Good brake fluid. Anybody know what I could have done???

 

master cylinder. (Pedal goes to floor, no leaks, fluid full) Get a new one, not rebuilt, Bench bleed it before installing it on truck. After installed, crack both lines, have someone push pedal down 1/2 way, hold and close lines, do this 3 or 3 times. With lines now closed, then pump it up , hold and crack each line until there is no air. 3 or 4 times. Good to go!

 

Forget to hook up the brake booster hose? Shouldn't cause "no brakes", but it would eliminate the power portion of the brakes.

 

brake pedal hard to press? check vacuum hose on back of intake manifold

 

Brake pedal is very hard to press. The physical linkage to the brake pedal is secure. I have checked, checked, checked....all the vac lines as well as electrical comnections. As big of a coincidence as this seems, can I assume that I have a bad brake booster?? I was wrong in my initial post about the pedal going to the floor...it does not.

 

pull the hose off the booster with the engine running. do you have vacuum? if you do then the hose is connected, if not follow it back to the intake. if you have vacuum to the booster, reconnect the hose, shut the truck off, pump the brake pedal and hold pressure on it then start the truck. if the pedal does not drop slightly you have a bad booster.

 

I do not have vacuum on the hose when I pull it off the booster. All visible lines are connected. One branch of the line drops behind left valve cover. That line will be harder to trace. The line that drops behind the left valve cover is the only vacuum line I messed with as I did my timing job. I manipulated it a lot but I never removed it. If I pulled a line off back there it will be difficult to see and fix.

 

That's were your problem is...that is the same line that there was a recall for very difficult to put back on. Easiest way is to take intake back off

 

I should have posted this months ago but my brake problem was due to vacuum line being pulled out of intake. Very hard to get to. I had to pull intake off to get at it. Brakes work great now.

 

Thanks for posting.