Brake pedal slowly drops nearly to the floor when applying pressure?

TESS1253

MEMBER
2003 DODGE DURANGO
4.7L
V8
2WD
AUTOMATIC
107,000 MILES

Several days ago, I was driving and while waiting at a stop light the brake pedal began to slowly drop almost to the floor. As I continued to drive, I had to pump the brakes repeatedly to get the pressure back up. I took it to a shop. They replaced the rear brakes and changed brake fluid. The problem continued. They replaced the master cylinder and bled the brakes repeatedly. Problem continued. Took it to another mechanic who trouble shooted for 2 days, bleeding brakes, etc. Still no resolution. Does anyone have any idea what the problem could be?

Saturday, September 9th, 2023 AT 12:19 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

When the brake pedal does this, normally there is either a leaking hose, faulty brake master cylinder, or a rubber brake hose.

If you turn the engine off and pump up the brakes and then hold pressure on it, does it slowly go to the floor?

Do me a favor. Have a helper pump the brakes and hold pressure on the pedal while you inspect the rubber brake hoses at the brake calipers. Make sure they aren't expanding.

Let me know.

Joe

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Saturday, September 9th, 2023 AT 9:37 PM