Master cylinder going bad????
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Master cylinder going bad????
I have a 1985 F350 7.5 2wd dually. How do you know when your master cylinder is going bad?
A week ago my brake pedal became very "spongy". Now every time I step on it, it goes to the floor. My brake light (on the dash) flashes on/off. I checked my brake fluid reservoir when it first happened, and it was empty. I refilled it, and it hasn't been leaking anywhere. I can't find any leaks in the system anywhere.
A week ago my brake pedal became very "spongy". Now every time I step on it, it goes to the floor. My brake light (on the dash) flashes on/off. I checked my brake fluid reservoir when it first happened, and it was empty. I refilled it, and it hasn't been leaking anywhere. I can't find any leaks in the system anywhere.
Mountain Pass
Joined: Jul 2014
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I would bleed the lines before you do anything. If the reservoir was empty you are sure to have air in the system.
Edit: That being said, I had the exact same problem. A re-manufactured master cylinder was $17 so I just changed it.
Edit: That being said, I had the exact same problem. A re-manufactured master cylinder was $17 so I just changed it.
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From: Virginia
If the master is bad, it will usually leak externally or internally. If it leaks externally, you will see a wet spot underneath on the brake booster below where the master mounts. If it's leaking internally, you will be sitting at a stoplight, and start noticing your foot is slowing sinking to the floor.
Since you had to add fluid, you have a external leak somewhere. If the booster is not wet behind the master, then I would pull all the wheels looking for a leak at the rear wheel cylinders or the front calipers. I would also look carefully behind the side gas tank along the frame, the lines like to rust through in that area.
Since you had to add fluid, you have a external leak somewhere. If the booster is not wet behind the master, then I would pull all the wheels looking for a leak at the rear wheel cylinders or the front calipers. I would also look carefully behind the side gas tank along the frame, the lines like to rust through in that area.
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