Hard Brake paddle

[Rope]

I have a braking problem, about three weeks ago my girl car which is a Mark VII brake and anti-lock light started to come on, sometime the light will stay on and other time they don't come on at all, so about two week after they started to come on the my brake peddle started to get real hard and then it will go away, now the light stay on and the brake peddle stay hard, the car will stop but I have to push real hard on the peddle to stop the car, any idea what could cause this problem

SOME BODY
HELP
THANK

 

[Joeychgo]

IM not super knowlegable about brakes - but my first guess would be the master cylinder

 

[Sifrino3]

Hey, yep thats my problem right now! For the second time!

 

[softailboizzindy]

I have had this problem as well! my case turned out to be "contaminated brake fluid" I guess somehow water/dirt was getting into the fluid and had that main ABS valve confussed. So a flush and bleed the brakes again solved it. The Tech at the shop did tell me to with the car off, pump the brakes to the floor 20 times and on the last time hold down for a minute. then wait a few sec and start the car. Then the pump will repressure itself with new fluid from the mastercy, It worked till I was able to take it in...

 

[WALT]

Dont know what year your working with but unlike most cars that have a vacuum booster and standard brake master cylinder --these babys have an electric hydraulic brake pump and master that is part of the anti lock system -- Fluid contamination is always a good place to start but there are many things like low fluid level or imbalance in braking pressures / brake pump or pressure switch that can cause the light to come on -- You have to describe the sequence that this problem occurs -- is the car ok initially then gets worse when your driving or is it
bad in the driveway ??? --- does the light only come on when you are depressing the pedal or is it on all the time -- is the anti-lock light on at the same time or is it delayed -- The Anti-lock will come on as a response to a brake system problem even if there is nothinhg wrong with the antilock system itself -- the HARD PEDAL is what
we really need to focus on here and that can be the result of the Pump not running
--accumulator or pump pressure switch not working correctly or the more off chance that the anti-lock control valve is not porting pressure to the wheels-- There is also a brake pump relay in a cover right next to the master on the firewall that can be bad ( they fail on a regular basis ) If you run the tests on the relay and it is bad make sure that you only buy one from the Ford dealer -- Each one is unique and
the parts stores do not have them right --- ( major past experience problems)
There is a test connector in the trunk that you can plug an analyzer into
for the anti-lock system for fault codes -- Having the proper equipment and
the manuals for this system is almost mandatory for any kind
of troubleshooting --
I can send you the diagnostic pages if I know what year / model your working with
Happy Hunting
Walt

 

[Rope]

Dont know what year your working with but unlike most cars that have a vacuum booster and standard brake master cylinder --these babys have an electric hydraulic brake pump and master that is part of the anti lock system -- Fluid contamination is always a good place to start but there are many things like low fluid level or imbalance in braking pressures / brake pump or pressure switch that can cause the light to come on -- You have to describe the sequence that this problem occurs -- is the car ok initially then gets worse when your driving or is it
bad in the driveway ??? --- does the light only come on when you are depressing the pedal or is it on all the time -- is the anti-lock light on at the same time or is it delayed -- The Anti-lock will come on as a response to a brake system problem even if there is nothinhg wrong with the antilock system itself -- the HARD PEDAL is what
we really need to focus on here and that can be the result of the Pump not running
--accumulator or pump pressure switch not working correctly or the more off chance that the anti-lock control valve is not porting pressure to the wheels-- There is also a brake pump relay in a cover right next to the master on the firewall that can be bad ( they fail on a regular basis ) If you run the tests on the relay and it is bad make sure that you only buy one from the Ford dealer -- Each one is unique and
the parts stores do not have them right --- ( major past experience problems)
There is a test connector in the trunk that you can plug an analyzer into
for the anti-lock system for fault codes -- Having the proper equipment and
the manuals for this system is almost mandatory for any kind
of troubleshooting --
I can send you the diagnostic pages if I know what year / model your working with
Happy Hunting
Walt

It is a 1990 Mark VII, the anti-lock and the brake light stay on all the time and brake stay hard, :sleep: I haven't try to do any thing about it yet bcause we used my Mark VIII.

 

[American Air-1]

The problem usually starts out as a weak accumulator, but winds up taking out the pressure switch along the way. When the light(s) were coming on before, that was the accumulator showing a problem and your sign to do something. Now that the brake pedal is hard, most likely the pressure switch has gone bye-bye.

I wrote an article about this on my site if you want to check it out: http://www.americanairsuspension.com/BRAKES MK 7.htm

 

[WALT]

90 LSC has hydraulic pump running the brakes --
First thing to do is figure out if the pump is running at all --
pump brake pedal several times then turn key on
and listen for pump motor running -- if it does not
run then you have to look at several components
Fuse links and fuses / bad motor relay / bad pressure switch /
or bad motor - pump assembly --
Troubleshooting Matrix out of shop manual will help
you find these components and how to test --