Brakes went to the floor!

[gollie]

1995 Disco. Many years ago, we removed the ABS (couldn´t get parts)
Yesterday, while driving, the brakes suddenly went to the floor. They pumped up a little, and I got stopped and started checking. No apperent leaks at wheels or in Engine compartment. Fluid level ok, but as wife was inside was working the pedal I noticed air like noise around the Master cylinder. found nothing,. Replaced fluid level cap, brakes pumped up and it´s fine now.
What could have happened? Will it happen again? Help appreciated!

[Disco]

It could be the brake fluid in the master cylinder overheated and boiled causing so air pockets to occur. Your brake fluid is old and needs replacing.

[pavel]

Gollie - seems to me that if it happened once, it'll happen again. There could be many reasons for this problem. That "air like sound" (hissing sound?) you mentioned its very odd....could that be the brake booster losing manifold vaccuum from the engine? Check the rubber hose going to the brake booster (and all other fittings really carefully). Good luck - don't let this problem go, as they say, it sounds serious.

[Disco Mike]

Originally Posted by gollie

1995 Disco. Many years ago, we removed the ABS (couldn´t get parts)
Yesterday, while driving, the brakes suddenly went to the floor. They pumped up a little, and I got stopped and started checking. No apperent leaks at wheels or in Engine compartment. Fluid level ok, but as wife was inside was working the pedal I noticed air like noise around the Master cylinder. found nothing,. Replaced fluid level cap, brakes pumped up and it´s fine now.
What could have happened? Will it happen again? Help appreciated!

No one likes to guess when it comes to brakes, the air hissing sound concerns me. If nothing else is found, at least do a complete brake flush, you'll need just under 3 pints of fluid, and a gravity bleed is the easiest way to go.
Be careful when you first start driving, make sure that it is OK.
Good luck,
Mike J.

[Rovin4life]

If you lose manifold vacuum the brakes get hard, they dont go to the floor.

why did you disconnect the abs pump in the first place.

what was the problem?

[p76rangie]

A small hole in a brake line can cause this problem. I had this problem that only under extreme pressure (emergency braking) would it leak and the pedal would go to the floor, it was fine under normal braking.

Ian

[Disco Mike]

Ian,
not the case here, he has stated the fluid level is holding,
Mike J.

[Rovin4life]

could be leaking into the brake booster.

[gollie]

Drove it all day yesterday, good pedal, no sign of leaks. I´m going to do a fush and change fluid as recomended. Thanks All!
ps. I live in Costa Rica, and it,s extreamly hard to get parts here. That´s why I removed the ABS system. Too many problems getting sensor parts!

[Bogatyr]

gollie,
Unfortunately, I don't think changing the fluid is going to help you at this point. I usually equate a pedal sinking to the floor as the MC has failed. Over time, as the fluid get's thicker with crusty rusty bits, some will lodge between the seal and the bore, eventually compromising the seal, fluid will seep past and the pedal will drop. So, that's answer number 1. If there is a loss of fluid, it'll end up in the booster, eventually attacking the diaphragm and could cause that to be compromised as well, causing a vacum loss.
I did have a situation on the series truck where I had a hissing with a soft pedal, but a new MC...changing out the servo fixed that up nicely. So, I'd expect to replace or rebuild your booster as well.

Bogatyr

[TerryS]

I think Bogatyr is on the right track. There is a small check valve on the end of the piston of the MC. Crud gets beneath the seat and it will just bypass, allowing fluid to pass to the other side of the main seal, with no pressure to the brake lines. Flushing may cure it, but the kit to rebuild the non ABS MC is very inexpensive and well worth the effort.