97 dodge caravan brakes

My 97 Grand Caravan brakes worked fine. Then on one real cold day the pedal started going almost to the floor. I pumped it a couple of times and it was
ok. It does that every time. The fluid level is ok and it stops even without any pulling. Also, I didnt see any leakage on the backing plates or concrete. Does this sound like the master cylinder and how can I make sure before I change it? I have replaced the front pads and rear shoes within the past 10 or 12 thousand miles. I think Im on the right track but would like any advice or opinions before I condem it. Thanks for any advice. Larry
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One way to tell you've got a master cylinder in need of repair is to sit with your foot on the brake pedal (engine running, for the boost), as though you came to a stop. If the pedal sinks slowly, the master cylinder needs repair.

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One thing more: The brakes will stop the car at any time-even without pumping. It stops as if either the front or rear system is not working. If its pumped up, the pedal is at normal height/position.
Thanks for any help

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Considering that modern cars have dual braking systems (how many wheels are on each line depends on the manufacturer), it sounds like one of the dual sections of your master cylinder is shot. Or one of the systems has too much air in the line...

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I agree. That is what it seems like but I am getting no brake warning light.

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Could be that the dual circuit master cylinder is so messed up that it won't even report that it has a problem. Suffice to say, you really want to have that master cylinder looked at, even if it's just a massive need for bleeding the system (and checking the warning light circuit). (Note: many mechanics hate bleeding brakes [as a standalone job] -- it's labor intensive and they can't charge as much for it as they can for installing new parts. If the new parts require bleeding the system, they make up the money on the labor in the markup on the parts...)

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On Mon, 05 Mar 2007 20:40:55 -0500, lama wrote:

This is an interesting problem , let me know what you find. I have a friend who is a mechanic who has this problem on a '95. He replaced everything, used the scan tool, bled them according to specs, and still the pedal would go to the floor. I drove it, I was going to buy it but it wasn't a long WB model. Stopped fine, just every once in a while the pedal would go right to the floor!
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