brake problems

[toby2tongues]

So here is the situation...having some brake issues.

I am loosing brake fluid to the front calipers. takes about 6 months to run the master cylinder dry. I have inspected the lines all the way to the calipers and nothing.

second problem, getting a little air into the rear lines...again, no obvious leaks

finally, when I am at a stop with the brake pedal depressed, the dash brake light comes on.

the pedal is not going to the floor, after bleeding the brake lines, the firmness of the pedal changes very little. at speed, the responsiveness of the braking system is probably 90%, when coming to a stop, the rear brake lock up the tires when on wet or icy surfaces.

whattaya think?...possible master cylinder leak down the piston into the brake booster then deteriorating the diaphragm in the booster causing a vacuum leak triggering the dash light?

 

[Clb]

Rear wheel cyl's puckin into drums!?
High mileage worn parts.
Fluid does not evaporate thus its going somewhere.....
The mc could be pucking into the booster.
Time to get dirty, 6 months to drain the reservoir means you have had time to fix it.
Brakes are kinda important

 

[toby2tongues]

no fluid leaking into the drums...completely agree, this stuff doesn't just disappear...its gotta be going somewhere. all my experience leads me to believe its going into the booster, but I just wanted to run this by you guys to get a few extra opinions before i go to buying parts with money that I have yet to figure out how i am going to get.

as for high mileage wear, the truck only has 22K original miles, but it sat in a warehouse from 1985 to 2015, so needless to say, there was some rot in all things rubber.

as for having had time to fix it, the only reason that i know that it takes 6 months to empty the MC, is that, six months ago I flushed the old brake fluid, and last week, the pedal went to the floor, checked the MC, and it was dry (there is no noticeable reduction in fluid at the moment)...brakes are not something that i put off...especially on a truck that weighs 3 tons.

 

[Clb]

If you have traced ALL the lines front to rear and found no issues, and the calipers and wheel cyl's are bone dry the only thing left is the mc....
I know its hard to believe at 20 k anythig is wrong with the rig...( mine has 40k) but the rubber gets sediments from long term non use at the bottom of the bores that turns to sandpaper next time its used.
My willys was famous for this phenomenon.
That's my 2 cents worth.
These abs units suck more than the newer ones.
Check out the hydroboost threads.

 

[toby2tongues]

copy that...thank you