Hi,

I have a 71 Chevelle , drum brakes(Power) and haven't used it in a year.The brakes were always great,but when I got in the car the pedal went to the floor.I checked the master cylinder and all the fluid was gone. I checked everywhere, but there are no leaks.I filled the master with fluid and its been holding it.It was a new master.

I tried to gravity bleed the brakes ,but there not as good as they were. I can hear a air/suction sound in the car when I step on the brake pedal, but to be honest I don't remember hearing it before.

Could the booster be bad? How do you know if the booster is bad?
I not sure what to do to correct the problem


Any Info would be appreciated !
Thanks
Tom

Are you sure it isn't under your carpet and firewall insulation?

pdq67

My friends 63 vette was like that too. We started it after 3 years of sitting idle. He backed in out of the garage and the pedal went to the floor. The following week we took the wheels off and no sign of fluid anywhere. Still the biggest mystery? We filled and bleed the system; it has been perfect ever since. The vette has a single master cylinder and is all drums. Note: I did not know the history of this car previous to me helping him so I'm not sure what really happened.

My Jeep cj7 has the same fluid fairy dilemma if I let it sit for long periods it will be out but fine once I start using it again.
No signs of fluid can it evaporate?

I would suggest looking under the dash and see if your getting any fluid back there also.

Have you pulled the drums and checked? If you have a slow leak, the fluid can get mixed with dust and turn into a gooey mess inside the brakes, without showing anything on the outside.

Thanks for all the replies!

I spent a whole day checking the brake system and found no leaks , no fluid under rugs , etc. I bleed the system and the brakes are not good. When I told a friend ,that I had to stand on the brakes to get the car to stop.He said the fluid probably leaked back into the brake booster and eat a hole in the diaghram.He said that the booster was shot.It also causing that air sound that I hear when I step on the pedal.
So I bought a new booster. I let everyone know how I make out.

Thanks Again
Tom

Thanks for all the replies!

I spent a whole day checking the brake system and found no leaks , no fluid under rugs , etc. I bleed the system and the brakes are not good. When I told a friend ,that I had to stand on the brakes to get the car to stop.He said the fluid probably leaked back into the brake booster and eat a hole in the diaghram.He said that the booster was shot.It also causing that air sound that I hear when I step on the pedal.
So I bought a new booster. I let everyone know how I make out.

Thanks Again
Tom

This is exactly what I was going to tell you to check. If the booster is leaking and the master cylinder has a bad seal at the back, your fluid is going into the booster and eventually into your engine, this is why you don't see any leaks anywhere.

Problem Solved !!!!

The master cylinder which was new when I put it on the car ,slowly leaked into the booster and killed it.When I got the old booster off, the fluid just poured out of it.

So I replaced the master , the power booster, bleed the system and everything is back to normal. I guess its just not good when you don't use the car often enough and it just sits.

Thanks Again