Master Cylinder Trouble Shooting

[jj1947]

Hi Everybody this is my first post so please dont jump on me if I dont follow proper protocol.

I have been having the normal it seems problems with my BA fairmont front brakes experiencing wheel shudder and seeing we solved this problem with my sons Late model camira I thought I would go down the same path with my BA but after 9000km give or take a few hundred the shudder returned and so I have started in search of the holy grail and seek a perminent fix so in order to make sure all the brake system was in good condition I put the car in to my local garage for the first step to have the hydraulics flushed and new oil placed in the system as the old stuff was looking rather black and after 145000km I suspected the origenal brake fluid I then had the new 9000km ago rotors machined but since fitting them I have noticed that the brake pedal was taking up lower than normal after conducting a stand still pressure test by keeping your foot on the brake with pressure I observed the pedal very slowly progressing to the floor a sign that the master cylinder has internal problems but the next day when I was getting ready to front up to my local parts place and purchase a new master cylinder tha brake pedal has returned to normal height and the pedal cant be made to drop the floor under pressure anymore I am suspecting foreign matter from the flush had lodged onder brake rubbers but cleared under pressure does anybody have any comment this unique problem all comments welcomed at this stage I would appreciate any help I can get.

[Ralph Wiggum]

Air in the system. what brakes are on it? standard or premiums?

[jj1947]

Air in the system. what brakes are on it? standard or premiums?

I had the system flushed and new fluid added plus power bled there is no air that I can detect in the system what I suspect is that some crud was lodged under the brake rubber causing a bleed past hopefully it appears to have cleared but the pedal seems slightly lower but acceptable and not falling away under pressure for the moment

[jj1947]

I had the system flushed and new fluid added plus power bled there is no air that I can detect in the system what I suspect is that some crud was lodged under the brake rubber causing a bleed past hopefully it appears to have cleared but the pedal seems slightly lower but acceptable and not falling away under pressure for the moment

also in regards to brakes they are standard rotors and pads freshly machined rotors.