I have a 1994 ford f150 4x4. Not a daily driver may sit for a month or two at times. I started it yesterday to make a 800 mile trip. Brakes where fine for the first 400 or so miles. They started to pulse, as I drove further I had soft brakes or no brakes had to pump the just to stop truck. Now I start the truck and pedal goes to floor, with little or no brakes. No lights ever came on. Where do I start, 3 months ago I replaced front brakes and everything was fine.

 

I would pop the hood and check the fluid in the master cylider and go from there. If there isnt any id say you just ran out (been there due to the drain screw on bottom leaking). If you can check the brake hoses on the calipers but youd need to take the wheels off. If theyre good you could have broken a line, check along the frame for a break, one line sweeps under the front axel to the right wheel, the main thing is you didnt lose pressure while going 60 mph....so be glad.

 

I agree to check for leaks but you should have the "brake" and "abs" lights if your fluid is low (I know I just blew a line, luckily in my driveway). My guess would be that the master cylinder failed.

 

Thanks but the fluid has not dropped, I checked for leaks but cant see any. all well cylinders and lines look good have been replaced in last year. unfortunately I was going 75 when they did decide to not work.

 

Well at least your ok. If the master cylinder looks old it could be that. Easy fix, like 40 dollars for a knew one and all you need to do for install is unhook abs sensor from the top, undo the 2 lines on the side and bench bleed it before you put it back on the brake booster. 2 hour job max. Best way to bench bleed is to either put fingers over it uninstalled and push through the inside with a decent sized flathead, or install it and hold fingers over ports while someone hits the brake pedal, then reconnect lines and bleed all brake areas.

 

Btw make sure fluid is inside the resivior when bench bleeding!