Spongy Brake Pedal on 97 Ford Escort?

[Mr_Accord]

I just recently got an old, yet well running 97 Ford Escort Wagon. My father and I just yesterday finished running two new rear brake lines as the original ones were really looking corroded so we decided to change them, rather than having problems down the line. We filled up the reservoir with DOT3 when everything was back together and then began testing the line by pumping the pedal many times to pressurize it. After a few minutes of looking around we found no leaks. We then began going from back to front bleeding the whole system until there were no air bubbles coming out of the bleeder valves. Now i'm not sure if this is normal or not, but if you pump the pedal with the engine off it becomes harder with every pump until you can't anymore, but if you come back say an hour later the pedal is lifeless...no pressure until you pump it a few times again. I thought the pressure was supposed to remain trapped in the booster when the system is off. Also when driving, the pedal is super spongy and goes almost to the floor, and when you really give the pedal a good hard push to the floor the cars begins to slow down , but the wheels don't even lock up a bit. So what is causing this? a master cylinder issue or brake booster?

FYI: we went around as well and inspected,greased, and cleaned all the pins and sliders. The discs and pads are in good condition.

Thanks

 

[jsnyder49090]

Could be many things, the backs probably need adjustment and the fronts are doing all the work.Did you get all the air out?I would gravity bleed all 4 just make sure you keep the reservoir filled just to make sure there is no air.

 

[AVB]

It is not the booster, it could be the master cylinder. Try pumping the pedal then hold constant pressure on it. If it drops it is probably the master cylinder.

 

[JamesBond]

How was the pedal before you started working on it?

I had an old car that I bled a few years ago but never liked the pedal feel afterwards and figured I just had worn out master cylinder seals (still stopped fine). I bled it again a couple of years later and got great pedal feel out of it. The moral of the story is...BLEED IT AGAIN.

 

[Mr_Accord]

Originally Posted By: jsnyder49090
Did you get all the air out?


I'm pretty sure we got all of the air out. We let a lot of fluid come out of the bleeders. We used just over a quart of DOT3 to get the system going.

 

[Mr_Accord]

Originally Posted By: JamesBond
How was the pedal before you started working on it?

I had an old car that I bled a few years ago but never liked the pedal feel afterwards and figured I just had worn out master cylinder seals (still stopped fine). I bled it again a couple of years later and got great pedal feel out of it. The moral of the story is...BLEED IT AGAIN.


It was more spongy than it was now, but the car barely stopped.

 

[Mr_Accord]

Originally Posted By: AVB
It is not the booster, it could be the master cylinder. Try pumping the pedal then hold constant pressure on it. If it drops it is probably the master cylinder.


I did that and held it for at least 30secs- 1min and the pedal didn't lose pressure.

 

[JamesBond]

I don't know much about physics or fluids or whatever, but I had trouble bleeding a clutch one time. No matter how much I bled it (vacuum bleeding, 2 person method, hose submerged in fluid method, gravity) I could not get pedal pressure. I pictured (my theory) a bubble in a high point in the line that would move closer to the bleeder when the pedal was pumped but then move back to the high point when the valve was closed and the pedal pulled back up. AND would basically sit in place when gravity bleeding. I determined that I needed to vacuum bleed with my Mityvac while topping off the tiny reservoir until I had a full "lines worth" of fluid pulled from the system at one time. I vac-ed from the bleeder while a second person kept the reservoir full and this method worked the first time!

The point is that your lines (maybe the new lines) may have a high spot that has a bubble in it that is not pushed out with a single stroke of the pedal. Try vacuum bleeding from the bleeder, or pressure bleeding from the reservoir.

 

[AVB]

If it has ABS, try some panic stops in grass or dirt where you can get the tires to lock up. Activate the ABS and hold the pedal down untill it goes all the way to the floor.

 

[mechtech2]

When you pump the pedal with the car off, there is no vacuum assist, and the pedal gets higher and harder.
Also, the drum brake shoes are pumped closer to the drums. After resting a bit, they return and a longer pedal travel is felt.

I am not 100% sure of your bleed, either. Are you?