My wife was driving our 2000 Ford Taurus (211K miles) the other day and said she went to brake and the pedal was soft. She said it only happened once. I have since driven it a few times, as has she with no issues. What could cause this sort of issue? Fluid is full.
Intermittent braking problem
- Thread starter gregk24
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Sounds like a master cylinder problem. Does it do it in a specific way, my old ranger did something like that and it was the master cylinder. mine would go to the floor if i went slowly but worked if i was a bit more aggressive. Could also be the brake booster but i don't know much about them,
Like I said, it only happened that one time that I am aware of. We have been driving it for around 5K miles and no other braking issues other than this event.
I suppose that could be the cause, though not likely as this has been a Florida car all it's life. It is not often you see brake line problems here. I suppose we will continue driving at this point and monitor.
...the master cylinder is bypassing fluid...it starts off like this and will get worse...
You mean you had a potential brake problem 5K mi ago and are just now getting around to it? Okay...
How long ago was any maintenance or inspection done, like at least pull wheels to look at it, or flush the lines with new fluid? At the very least I'd inspect all four corners before driving it again, after that event.
FL car doesn't necessarily affect your soft (rubber) lines being reliable at this age, unlike the hard lines which may have less rust than in some other areas of the country. At 22 y/o I would replace the soft line hoses if still original or you don't know, as they are probably only $15-$20 a piece or so on Rock Auto, then flush out all old fluid during the bleeding.
The idea is if it's due for these things, might as well get them out of the way but I also wonder if you might have had a pad dragging, excess heat, water vapor, compressed the vapor when applying the brake that one time. If you're not sure if your caliper slider pins were lubed with something long lasting (like silicone paste instead of petroleum based goop, or even worse the last shop that did the brakes just did a pad slap so you now have pretty old petroleum based grease that's exhausted) I'd look at that too.
Nick1994
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I had that with the Camry. Wasn't noticeable at first unless I braked a bunch of times in a short period of time, then it would lose pressure. Was the booster.
Not hard to replace.
Not hard to replace.
Agree. A seal is bypassing fluid under low foot pressure but holds under more firm application- it "balloons" more out under pressure and makes a better seal. Could also be the booster. Pull its vacuum line and look for engine oil.
I believe there was a test you could do to see if the master cylinder was going/is bad...not sure how reliable (the test) is, but you can try it out...
I'm guessing this test assumes you have no air in the system or any other leaks down stream...
With the vehicle OFF...press/pump the brake pedal several time to remove the vacuum from the system...the pedal should get firm.
Then with all the vacuum assist removed...FIRMLY press on the brake pedal and wait. In a good system the pedal should stay firm and keep its position. If the master cylinder is leaking, the pedal will slowly lose it's firmness and start to go down.
Again, now sure how reliable this test method is with modern vehicles...
I'm guessing this test assumes you have no air in the system or any other leaks down stream...
With the vehicle OFF...press/pump the brake pedal several time to remove the vacuum from the system...the pedal should get firm.
Then with all the vacuum assist removed...FIRMLY press on the brake pedal and wait. In a good system the pedal should stay firm and keep its position. If the master cylinder is leaking, the pedal will slowly lose it's firmness and start to go down.
Again, now sure how reliable this test method is with modern vehicles...
ABS self test ? Pedal tends to to down during the ABS pump cycling. Keep and eye on the fluid level. But you have dual circuit brakes. Its not like the old days when you had to use the E brake when a line or cylinder went.
You could also have had a bad seal on one circuit temporarily.
Did you do a turkey baster reservoir fluid renew?
You could also have had a bad seal on one circuit temporarily.
Did you do a turkey baster reservoir fluid renew?
I went through this with my first car, (low-pedal-pressure MC bypassing) and I have to say, if my wife was driving around in a car that EVER displayed this behavior, work would be done before it catches her off guard and she hits someone. The first time my pedal went soft, I was approaching stopped traffic at 50mph, and it took some pumping to get a response. I got stopped. She may not be that lucky.
My advice would be to replace the MC now, and consider replacing soft lines at each corner. 21 years and 200,000 + miles is a long road for rubber hoses.
My advice would be to replace the MC now, and consider replacing soft lines at each corner. 21 years and 200,000 + miles is a long road for rubber hoses.
If I remember correctly it has rear drums. I would pull rear tires and check wheel cylinder for seepage.
No. We have owned it for a total of 5K miles. The issue just happened.
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