hard break pedal

hi all
i have a p reg 300tdi.
i wet through a 'low' ford yesterday when dropping my son off and on the way home all was fine. when i went to go back out in the car an hour later, my brake pedal is extremely hard and is not compressing much and is not stopping the car. i have read up on google and the general consensus is the master cylinder. does this sound like i am on the right track. my partner will be checking the car over when he returns from work but thought i would do a bit of research first. we need to tow on sunday so a fix will have to be performed tomorrow. i know i should take it to a garage but don't fancy driving it with my son in the car and risk an accident.

any help will be appreciated.

Sounds more like a brake servo fault to me.

The seals in an old master cylinder can start to break up an a small bit can partially block the outlet. Needs immediate attention!

HenryD said:

Sounds more like a brake servo fault to me.

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+1 ditto.

Sounds like servo had the same effect on my mk1 Astra but can't you hear pressure escape when servo is fooked ?

Just looked in Haynes book under faults it says faulty vacuum servo unit or disconcerted Danegeld or insecure brake servo vac hose , faulty brake vacuum pump , primary or secondary hydraulic circuit failure and a few more to do with pads

If the servo was not working the brakes would still work,you would just have to press harder.sarahriley1983 says brakes are not working.The pedal being hard and not moving much indicates a blockage.

If you're used to servo-assisted brakes, non servo brakes will feel like they are not working as you have to press them sooooooooh much harder.

As the biglad says if servo is not helping pedal feels rock solid and no stopping power .
Can be scary on a car but the added weight of the Disco would make it almost impossible to stop .
One check for servo is to
(a) with engine off press pedal a few times to discharge servo ;
(b) then with brake pedal pressed start engine :
(c) if servo is working you should feel the pedal go down a little as the servo begins to
help ;
Check pipes to vacuum pump ; diaphragm in pump may be split .
As advised I would not drive it until this sorted - you can easily build up a little speed and then find it impossible to stop ; pedal feelin like a stone under your foot .

Well we found the problem. The vacuum pump seal was hangin off. Some of the rivets had gone. Thank god it was a quick fix and thank you all for your input. It has restored my faith in owners club forums.