soft brake pedal

[250k...onthesteeringwheel]

Re: 1995 Windstar

About 3 years ago, I started getting a pulsing feeling in the brake pedal when braking hard. The pedal would also drop a few inches, but I could still stop. The pulse does not affect the steering wheel and I can't really feel it in the floor or seat. It is just a pulsing pedal and pulsing noise. At the time, I was told it was a valve in the ABS system that would cost ~$1400 to replace and that the rest of the brake system would continue to work, if I could deal with the noise. I dealt with the noise.

Over the last 3 years, the pulsing feeling in the pedal has advanced from only sudden hard braking to every time I stop. It doesn't happen at speed. Only when stopping. The pedal no longer drops while braking either. Now, it is just always spongy. This weekend, I replaced the front pads and inspected the front rotors and calipers and the rear drums. All of which looked fine. The master cylinder had plenty of fluid and showed no signs of leaks but I replaced it anyway since that seemed to be the likely culprit for a soft brake pedal. My braking distance seems to have improved slightly, but I still have a soft pedal. I bench bled the master and gravity bled all four wheels. The only thing of note was that the rear passenger side wheel never seemed to pressurize. Instead of spurting when I opend the valve, it would always dribble out, even after ~5 tries.

Could whatever is causing the low pressure in the rear passenger side wheel be causing the soft pedal? Something else? I have been driving this van since my family bought it new in 1994 and I have replaced/rebuilt the engine and transmission in the last 3 years. I am happy to continue driving this van until it falls apart around me but I am worried about the safety consequences of not being able to make a sudden stop in case of emergency.

Any ideas you may have would be appreciated.

[spongybrake]

Hi, this is my problem, very likly the same your have.
My 98' Ford Windstar has a spongy brake. It is 3.8 engine with ABS.
Replaced master cylinder to start with; new brake line, new brake pad,no oil leake, but air mixed oil in brake line after bleeding 3 times by the mechanic. went to a Ford dealership, using computer bled, no help. the third autoshop checked and bled again, no idea but said they will start changing brake volve, then replace ABS, then change computer, then change everything,........ my impression is they will assemble a new Ford.
the rubber brake line extentionn looks fine.

[mark v]

My Windstar always had a soft pedal since 50,000 miles, it now has 117,000 miles. These vans are not designed with hard pedals.

I worked at a Ford dealer back in 1994 when these fist came out and they all had soft pedals.

The question you need to ask your self is "does the vehicle stop when you need it to?".

[adrenochrome]

Well my van like you said has a soft pedal, but after a while got much worse and I did nothing to the system other than replace the pads and shoes with Bendix without opening the system but didnt get worse until long after that... WTF?

[mronning]

My 98 Windstar started having spongy brakes when we drove with the emergency break on and heated them up so much that the pedal went straight to the floor. After we realized what was going on and took the emerg brake off the brakes came back but every once in a while right at the end of the braking action they go spongy and chatter but never straight to the floor. THe mechanic has bled them manually and with a bulb 5 times each no air. We disconnected the abs by removing the fuses and it still does it. Recently we replaced the computer... still does it. I was thinking from what I've read here and on other sites that replacing the master cylinder isn't going to help either. What about a rear brake adjustment?

[mark v]

Any of you ever change all of your Brake fluid, you know a complete flush?

Also this system is designed to run on only 1 type of fluid too.

Every brake job I do the system gets a complete flush.

[adrenochrome]

I went through about 3 quarts of Prestone DOT 3&4 ABS synthetic brake fluid and it's completely clear coming out of each wheel. I looked at the rear brakes a few weeks ago and the drums are still rubbing the shoes when spun. I havn't replaced the master cylinder yet and im not replacing or bleeding any ABS units, screw that... It's not the ABS I ruled that out, no warning lights on either.

[mark v]

The rear shoes should drag a little.

System was not designed for synthetic, you might of damaged some seals.

Question did you pump the brakes to bleed the system or use a power bleeder?

Pumping the pedal to the floor can permanently damage an old master cylinder because the old M/C develops a wear in the cylinder and pushing it beyond the wear can rip an o-ring and cause internal leaking. I used to use a block of wood so the pedal couldn't be pushed farther than normal braking travel. I now just use a power bleeder.

[spongybrake]

mronning,
the mechanics adjusted the real cylinder. brake fluid bled to clear. ABS fuse taken out also,but no help at all.
my car can't stop safely, it takes longer distance; I hope Ford mechanics not stand in front of my car and get hit flying into the air ---since Ford believe the spongy brake is "normal",why not try stood in front of a vehicle with this "normal" brake?

[adrenochrome]

Ok im convinced its the master cylinder and im putting cheap DOT 3 in it this time... This dont work im selling it.