Master cylinder?
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Joined: Oct 2011
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Master cylinder?
Just signed up to help father in law. He has a 2003 f150 with the 5.4. His brakes get spongy sometimes. He has seen some fluid at the back of the cylinder and booster but not much or all the time. Ive read alot of posts and it could be a number of things. His fluid is dirty and he bleed the brakes months ago. That could point to the cap. Im just reaching for stuff from what I have read but hoping someone with more knowledge could help.
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Joined: Mar 2010
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You may have moisture in the system. The dirt you see is likely from corrosion/moisture. You can try flushing the system out with fresh fluid. Easiest way to do that is with a vacuum hand pump on each of the bleeder screws. Watch the fluid stream as you suck out the old fluid, checking for rusty looking contamination, and air bubbles. Per usual, start with R-R, L-R, R-F, L-F. Then see what you have.
It's possible that an O-ring is bad in the master, but check everything else first. Even a rebuilt master is a bit pricey. The small amount of fluid on the master and the booster may have leaked from the switch on the top of the master.
Make sure to keep the fluid level up as you purge the system. Even a small bubble of air can cause your problem. There is some history with the flexible rubber lines having collapsed inner linings or blockage.
If you do decide to change the master, make sure you bench bleed the thing first, or the spongy brake problem will be even worse.
Dave
It's possible that an O-ring is bad in the master, but check everything else first. Even a rebuilt master is a bit pricey. The small amount of fluid on the master and the booster may have leaked from the switch on the top of the master.
Make sure to keep the fluid level up as you purge the system. Even a small bubble of air can cause your problem. There is some history with the flexible rubber lines having collapsed inner linings or blockage.
If you do decide to change the master, make sure you bench bleed the thing first, or the spongy brake problem will be even worse.
Dave
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That was my opinion also. Start will the small stuff and then see what else. From the Ford dealer it was $285 they said and just over a $100 from autozone. He said he bleed the brakes a couple of months ago but cant hurt to flush the system with new fluid and go from there. I also asked about the hoses but he didnt think so. I said check again. Thanks for your help.
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