Brake system pressure and leak question.

[rjewkes]

Sorry when i searched no other topic on brakes covered my problem/question.


What is the pressure on the system supposed to be, and how do you check it?

I have all four Wheel cylinders less than a year old and bleeding works fine. none of them have a detectable lleak.

But I have had to add fluid once every 2-3 months.

The question is What makes the master clynder leak out the cap with a new seal propperly in place and the hold down strap tight as it can go?

Is this a stock ford Brake system problem or do i have a problem that is fixable?

[FLATBEDFORD]

I would say the master is leaking the fluid into the booster. From the booster, the fluid is getting sucked into the intake and burned with the fuel/air mixture.

[mr_josh]

I agree with Flatbedford.

The pressure in the brake system can spike over 1000 PSI. Lest anyone thinks that a power booster doesn't affect stopping ability, dig this cool chart that I found:

http://www.classicperform.com/PDFs/Boos ... eChart.pdf

[fordman]

it could be also that the shoes are wearing down and the system needs more fluid to reach the shoes final travel. but i doubt that is the problem. leaking out the lid is a different problem. i think that either has to do with a worn out lid gasket or some sort of clog if i rember right. i do remember a thread about that lately. around a month old. but it wasn't in the title of the post.

[FLATBEDFORD]

I think somebody, possibly the Kapt, was looking for a new gasket, but couldn't find just the gasket a few months ago. I say replace the master. You should be ablt to get one for around $40, and if nothing else, you will end up with a new gasket.

[rjewkes]

I would say the master is leaking the fluid into the booster. From the booster, the fluid is getting sucked into the intake and burned with the fuel/air mixture.

this sounds dangerous for the engine

Yeah a new master sounds like the way to go. or atleast seperating it slightly from the booster to see if the booser is sucking in leaked fluid.

Thanks guys.

[FreakysFords]

or atleast seperating it slightly from the booster to see if the booser is sucking in leaked fluid.

A little trick for ya. Pop out the vac fitting from the booster and insert a piece of small vacuum line (or use a long zip tie) as a dip stick. Often you'll find the fluid level about a third of the way up.
Any fluid in there is not a good thing, but if you have it that will actually show on the dipstick, save the trouble of "checking the master cylinder' and go get it's replacement. This isn't to say that if it's a fairly new MC you should trash it if you find fluid (can be from last bad MC).

Point is, I check the booster (on all my pwr brake vehicles) anytime I'm doing anything to my brakes.

To remove brake fluid from a booster, grab your handy dandy hand held vacuum pump w/ container (if no container, grab a lidded bottle of some sort that won't collapse under minimal vacuum and pop two lines in it. Make sure one goes down near the bottom and the other stays up @ the top. Suction from pump goes to the one @ the top and the business end goes to the one that goes near the bottom. Now you have a handy dandy miniature shop vac).

Now just vac it out.

[rjewkes]

Cool way to do it freaky, thanks.

[mrtleavitt]

When I did my swap, I had the same thing happen. Fluid would not stop leaking out of the top of the master cylinder from the gasket. So I bought a new gasket but it still leaked. So I doubled up the two gaskets (had to do a little trimming on one) and it hasn't leaked in over a year now. Give it a shot!

[tfnaaf]

Anytime brake fluid has entered the booster it should also be replaced. The fluid will cause premature failure of the booster