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Discussion Starter · #1 ·
I was reading an old thread from 2013 (2004 brake booster inop when below 20 degrees F) This website stated that this is an old article and I might not receive a response so I am starting a new one. So, here is what I was going to post there: I am pretty sure I am having this same issue. This past Sat. it rained, freezing rain, and snowed. And the next thing I know the brake booster was acting stoopid. Barely any boost just kinda running off the regular brakes I guess. So, is the check valve something a parts store has on hand? I have a 2008 Escape XLT AWD V-6. I mention replacing as a possibility because this old beast has 266,500 miles and it might be better to put in a new check valve. I have NO idiot lights coming on, either.
Hope this makes sense.

Later. Pepse.
 

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Most likely is ice freezing and blocking the vacuum or making the apply valve stick. When you step on the brake pedal, you open a valve that allows vacuum to pull on a large diameter diaphragm to help you depress the brake pedal. If that vavle sticks, no vacuum gets back there.

Or it could be water has gotten behind the diaphragm and the vacuum can't compress it. Or water has gotten into the vacuum line connecting to the intake manifold and formed a plug, either ice or liquid.
If you had any sort of vacuum leak, you generally would also have had rough idle issues.
One last is the booster is not getting vacuum due to a stuck check valve.
All that comes to mind right now.
tom
 

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Discussion Starter · #3 ·
Okay, so is the checkvalve inside the vacuum hose? I'm thinking of taking a hair dryer and warm up the hose if that is where the checkvalve is.
As for a vacuum leak? I am not noticing anything different in my idle nor can I hear any hissing.

Later. Pepse.
 

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New boosters seem to come with the check valve on it, being that right angled entry plug from the vacuum line. It looks like this plug can be removed from the booster, if I refer to videos of a booster replacement. Mine had the check valve inside the vacuum cable. I removed the cable, and I could feel the ball moving but not with a clear "click". My problem was not due to water. I put some varsol in the cable and shaked it. The ball started to click like it wasn't gummy anymore. The varsol came out dirty. Did it a second time. Pushed air in it to evaporate the solvent, and reinstalled. It never failed again. It's worth a try.
 

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Discussion Starter · #5 ·
smario259

Although the brake booster got back to normal this morning, I don't understand your commentary in regards to: "being that right angled entry plug from the vacuum line", to "Mine had the check valve inside the vacuum cable". Vacuum cable, NOT vacuum hose/line? I want to see if I can clean mine up, also.

Later. Pepse.
 

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Sorry, bad choice of word. I cleaned the vacuum hose with varsol. That was on a 2001 (this one had the check valve inside the rubber hose), but I see that my 2005 is different. A rubber vacuum hose, clipped to the intake manifold, connects to a plastic device that is likely the check valve. From the check valve a plastic hose with a corrugated protector goes to the booster. It has not failed on the 2005. The principle stays the same. Remove, inspect, clean, reinstall.
 

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Discussion Starter · #7 ·
Okay. Now I know what to do. Thank you.

Later. Pepse.
 
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