Brake pedal slowly dropping to floor under pressure.
08-30-2011, 04:52 PM
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Brake pedal slowly dropping to floor under pressure.
I have a 94 del sol. When I'm on the brakes it will slowly lose pressure and sink to the floor. There are no leaks at any corner of the car or in the bay. My first thought is the master cylinder is going bad. But I wanted to know has anyone had this problem before and what it was(i.e.master cylinder,brake booster, check valve, etc.) Its a stock d15b7 manual trans. All factory brakes, rear drums. Any input is appreciated. let me know if i left anything out that could help.
08-30-2011, 05:22 PM
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Re: Brake pedal slowly dropping to floor under pressure.
If you haven't bled them, do that first, but I'll put money on your master cylinder going bad. I've done 2 out of the last 3 of my vehicles, one of which was my 94 Del Sol. Air in the lines will make the pedal go down, but once it's a hard pedal, it doesn't leak down. Master cylinder.
08-30-2011, 05:31 PM
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Re: Brake pedal slowly dropping to floor under pressure.
bled them 3 days ago just to see if that was it. Didn't change a thing. The pedal is firm if you stab the brakes, but once you maintain pressure it starts to sink. I'm fairly sure it the MC but just wanted to make sure nobody has had the same issues with a different culprit
08-31-2011, 04:05 AM
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Re: Brake pedal slowly dropping to floor under pressure.
Take 10 minutes to put your car on jack stands and look at the pads and rotors, it could be a bad mc, but start with eliminating the smaller, easier to fix problems.