I have a 2000 XLT 3.0. I replaced the master clyinder and it failed because the booster was bad. I changed both and no more leakimg from there. The rubber part of the brake hose near the front left tire is wet from where it meets the metal brakline. The truck has the brake modulator. I bench bled the new master cylinder. I think I did it well. So the brake fluid was black. The pedal has not been good since I bought the truck less than a year ago. I bled all four brakes last week until there was no air. After I ran the ABS OBD tool to bleed the modulator. Pedal still soft but truck will stop. Yesterday I flushed the fluid out of the back right bleeder until it was the color of new fluid. But air is coming out. I went through 3 quarts doimg this. I keep trying to bleed it but air seems to remain in the system. I have had a better pedal before but still not great. I have the tool to bleed the modulator. But it seems like air is still in the system. Tips, information, ideas?

 

Reads like you may have a leak in the rear
What does the Flex line from top of differential to the frame look like?
Any wetness?

Or around the "T" fitting on differential, sometimes hard to see that area

You can just gravity bleed the system, takes awhile, but it reads like air is coming in from somewhere

Take cap off master
Open any or all bleeders and gravity will cause brake fluid to flow out of the bleeder from the Master, its not fast, lol

 

I have not checked rear differential. There is wetness on rubber hose leading to front caliper. It starts where the metal brakeline connects to the rubber. I'd like to just replace the rubber part but if its in the flange where they connect..... I could replace the whole line with the rubber section. Just afraid to let too much air into the modulator. About how long does gravity bleeding take? I suppose I have to watch the master cylinder so it doesn't run dry.

 

Air won't go in to an open connection, fluid should leak out slowly, then put the new hose on and wait for fluid to run out of it, gravity bleed, then connect the other end of the hose to caliper, with caliper bleeder open and then fluid will come out of caliper, system is bled
Its good to follow up with a regular bleed, either power or foot on the pedal help from a friend

 

Thanks.

 

Well I troed gravity bleed one at a time. Only got one done and never had any air come out. This truck has the abs modulator which the manual (Haynes) tells you only the dealer can bleed. It is above the master cylinder. The lines go up to it from the MC. So when you replace the MC air does get into those lines.
So there is a scan tool which will activate the hydraulic pump and bleed the modulator. Cheaper than Ford. But I have noticed since I started with the brake (changed out MC previous and then failed new MC and Braoe booster) that the pump is making less noise. It may be failing. I used to be able to hear it pretty well when it engaged. I am worried it is failing. And need to be replaced. Anybodybwith experience replacing this? Is it the whole modulator?