[fellro86]

My father recently acquired a second 84 F250 6.9, and it has lost brake fluid fairly quickly, but yet I can't find anywhere that it can be leaking out, had the drums off, no visual loss. The master also has been replaced, thinking it may have been the problem, but the same problem persists. Looking for ideas where to go from here...

 

[LongRider]

<font color="green">My truck did the same thing and it turned out to be getting into the brake-booster.

It did not show a wet spot anywhere; but, it would get rid of a quart of fluid pretty quick. </font>

 

[Mr_Roboto]

I've also had a master leak fluid into a booster. This was in a gasser so the engine ingested it.

The master leaks into the booster, which eats through the booster diaphram.... I'm sure it will eat through a vacuum pump diaphram too.

 

[fellro86]

when I took the master loose to check that, it was dry, no signs of fluid there...

 

[Joe Mc]

You have tried all the usual suspects, park it in a dry spot and pump the brakes about a hundred times. Look under the truck for a wet spot and follow the drips to your leak. You might have a hose or line leaking.

 

[fellro86]

Well, found out today that he replaced one of the wheel cylinders, as it was leaking pretty bad, so I advised him to do the other. We'll see if he listens... but I worked it abit today, and the brakes pump up real solid, the only wet area is the master itself, one of the lines had a shade of fluid on it. Both parts of the reservior get low, so it could be possible to have issues there...