Did I blow the master brake cylinder or the booster

[misfish]

Had a driver looking the other way, when he decided to pull out of a parking lot exit onto the main road.Had to slam on the brakes.Bit of a screech from the tire and then the pedal went to the floor.Swirve and thankfully I missed him.Got out, thought forsure I blew a line,but no wet spots.Pump the peddle and theres brake but the peddle goes to the floor slowly.What ya think?Fluid was down a bit.

 

Man Im glad I didnt hit this guy,would of been T-bone to the driver side.Not a sight I want to see again.

Edited September 25, 2010 by BrianB

[Fisherman]

What are you driving? If it has drums on the rear, then yes, maybe you pooched the seal on a brake cylinder, possibly an expanded rubber hose that go between the brake lines and calipers. Also like you said, if you were that low on brake fluid, bad boy, then you may have sucked some air in past the master cylinder seals.

[misfish]

Should of said Master cylinder. No brake fluid on the ground.So I dont think it,s a brake cylinder.

 

As for the level,it is down just a wee bit.

[Bernie]

Brian, the fluid is going somewhere.

Look closely at all the brake lines, sometimes the fluid can hide itself in framework and will take a while to run out.

Have someone depress the brakes while observing under the vehicle.

If that is OK then check at the rear drums (if it has them) and backing plates for wet areas. It may have developed a leak at the wheel cylinder.

Next look at the calipers for a piston leak.

Although it still could be a master cylinder I doubt it. Usually in a hard brake application it is a rusted brake line or a blown hose.

 

While I am at it here folks I might as well remind you all to have your brake lines inspected, especially if you live in an area where road salt is used.

We are replacing brake lines in vehicles that are rusted out that are only 4 or 5 years old.

It could be manufacturers are using cheap line but I think it is more likely the liquid road salt that is now being used in Ontario.

[misfish]

F150(no ford jokes, Im a loyal ford guy)

 

Yes I have drums in the rear.I have been under the truck looking,even after sitting an hour.No wet spots Bernie. Could I possibly have a calapsed flex line at the caliper.Would that do it aswell? Guess Im going to be ripping the rubber off in the morning to see whats what. Thankfully it,s a 5 speed.I was able to use the gears and the bit of brakes I have to get her home safe.

 

Thanks guys.

[Bernie]

Nothing to collapse Brian. Brake lines are all under pressure when applied.

There is a devise called a combination valve mounted below the master cylinder in the brake lines that may have shut off the flow of fluid to prevent further leakage Brian. Not sure what year your F150 is.

There will be a single line that runs along the inner part of the frame on the drivers side to the rear. On F150s the line usually lets go between the fuel tank and the frame. This is due to the moisture staying in that area longer.

Sometimes the fluid leak will trace itself along the fuel tank and be difficult to see.

[esoxansteel]

I drive F150s for work and had a similar situation where the pedal went to the floor as I was stopping for a red light, not as fortunate I rear-ended the guy that was stopped at the light, my other options were to hit a city bus or a young women pushing a baby stroller problem was brake sensor malfuntion that could be your situation

[misfish]

The year is 97 Bernie.

Why ford did this in the frame stuff ,kills me. I had a bad burning smell going on a few weeks ago when I turned on the blower fan.Turned out to be a broken ground strap in the frame.

 

Thanks again.

[skinny]

I have a 97 F150 and so far I have replaced the line across the front cross member and also the long line to the rear My long line had a connection just after it passed through the frame and it was right there where it let go. but it was hard to find was under truck 3 time them got mad and got in started the truck so power asist was working and jabed the peddle few times then stood on it and she let go big time that was how I found mine

[misfish]

Thanks skinny.Give that a try sunday. Replaced the long line to the back aswell.

[IndySKS]

Well these guys on here know a lot more than me but is the brake fluid still going down in the reservoir if you pump the brakes a few more times then you got a leak somewhere, if not ...well then something else is wrong. monitor the reservoir and that will be your first clue to your problem.

[Daplumma]

Good advice Bernie,I lost a brake line on my suburban.Replaced the line and another blew out when bleeding the brakes.Sold the truck the next day and told the new owner about the lines.Sure hope he replaces the rest of the lines.

 

Check to see if the back brakes are working,what Bernie said.If all work and there is no fluid loss then the MC is prolly pooched.I have heard of the fluid leaking into the booster and getting sucked into the motor thru the vacuum line.Dont know if this is possable in the newer motors though.Take a look for smoke in the exhaust when braking.

Joe

 

 

[misfish]

Well I found it. This morning there was still no sign of wet spots,so like mentioned,started it up,pump the brakes and well well well,it turned out to be the right front flex line.Small pin hole,right where the support clamp is.Wont cost an arm and a leg to fix.

 

Thanks guys for the help.

[IndySKS]

Well I found it. This morning there was still no sign of wet spots,so like mentioned,started it up,pump the brakes and well well well,it turned out to be the right front flex line.Small pin hole,right where the support clamp is.Wont cost an arm and a leg to fix.

 

Thanks guys for the help.

 

Soooo....are you going to replace both ? or go through this again...probably sooner than later...

[Bernie]

Glad you found it Brian.

 

For replacement brake line I am now using an iron free material.

It's easier to work with as well, bends and flares great.

It's a little more money but it is a final fix.