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Brake fluid leak

1507 Views 7 Replies 5 Participants Last post by  Steve83
So last night I lost about 90% of my breaking power. I popped the hood and noticed I was almost completely out of fluid and it was spewing out all over the leaf springs below. I filled it back up to get me to my destination and monitored it very closely. It has since gone down some, so there is a slow leak somewhere. I pulled the driver sides wheel well liner and inspected the lines that run on top of the frame and they all look good. From underneath, I reached up to the bottom of the fluid reservoir and my hand got coated in clear fluid so I think the leak is coming from there. Couple questions. There is a sensor plug on the bottom of the reservoir...what is that even for? And secondly, do I just replace the reservoir or the whole master cylinder? Truck has 303k miles and I've never touched the master cylinder and I don't believe the previous owner did either. Thanks!
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There is a level sensor on the reservoir. I believe it attaches to the plastic reservoir. Leakage could occur between the sensor and reservoir or between the reservoir and MC itself. But the Brake Pressure Applied sensor on the nose of the MC is more likely to leak, because it sees high pressure from the fluid when brakes are applied.
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