85' Chevy G20 No brakes!

[Taylor]

This is my dads old work van, so the best i can do is what he has relayed to me.....

Front reservoir, smaller of the two, keeps losing all fluid, no apparent leaks.
Hard Pedal, not mushy. Doesn't go to the floor, and does not help to pump.
No loss of fluid @ the rear. And it seems what braking is left, is coming from the front.

Bad master cyl, booster, kinked line, frozen calipers, bad vacuum line to the booster, or just a ton of air in the sys via a leak???

Any help is greatly appreciated .

 

[Colt45ws]

If it keeps losing all the fluid it is leaking somewhere.

 

[cchase]

The front reservoir is for the rear brakes. If it is going down, it's leaking somewhere (like Colt45ws said).

I'd open up the rear drums and check in there, the rear wheel cylinder (one or both) is probably leaking.

 

[FL_Rob]

The fluid has to be going somewhere,look at the front rubber lines youve got to microscope this thing, luckily you shimmy around and follow the lines to the rear to look for the leak.Do a total flush with new fluid.the rear brakes need to be manualy adjusted and cleaned and use the parking brake to allow the self adjusters to try to keep compensating for wear,the distribution block is easy to spot with the hood open,anything could be jammed in there.If no luck go straight to the master cyl for a rebuild/replace.
edit :a high pressure leak comes out in a mist not necessarily a drip.

 

[Taylor]

With the amount of fluid it losing, you'd think it would be visible on the drums, and/or ground. Considering the front brakes do most of the braking, and the front fluid level is fine, why is all the braking gone? It just seems like a booster, vacuum related issue to me. High and hard pedal, pumping doesn't change anything. Maybe the fluid is going into the intake????

If the front rubber lines were leaking, than the rear reservoir (front brakes) would be low, no? There is no visible leak at the distribution block or at the rear, I'm not sure about in between. Even so as I mentioned earlier, loss of fluid for the rear brakes why no front brakes?

If it was misting inside the drums, it would accumulate and drip no?

And a bad master would result in soft pedal to the floor, that could build up pressure with a few pumps no?

 

[cchase]

The way you describe fluid loss, it has to be going somewhere. There is a rubber line near the rear axle for the back brakes, but I suspect you would have dripping if it was originating there.

The reservoir for the rear brakes is significantly smaller than for the front brakes (drums vs discs require different amounts of fluid).

The first step would be adding fluid to the correct level in the front reservoir, then observing how fast it goes down.

Another thought (although this would probably lower both reservoir levels) is that the rubber seal on the top of the reservoir may not be seated properly and brake fluid is leaking straight from the reservoir.

Other than that, follow all the brake lines from the reservoir back to the rear wheel cylinders, open the drums, and go from there.

Most of what you speculate would probably impact the front and rear brakes equally.

 

[FL_Rob]

A rock hard pedal would be a bad booster or a bad vac leak at the booster hose.

 

[Dieselbob]

Perhaps the fluid is going into the booster. I've seem boosters that were full of fluid.

 

[mechtech2]

Being water soluble, brake fluid can gt washed off and the leak may not be apparent.
But you have a leak, for sure.

C'mon ... the level goes down and there is no leak?

 

[Taylor]

I never said there was not a leak.

 

[GMBoy]

Look under the dash near the pedals - boosters/master cyls will leak there and run down the firewall and under the carpet.