I recently had the front disks and pads replaced on the focus, with no issues, and the garage said the rears would need doing soon. Got the parts, and myself and brother in law (an ex mechanic), replaced rear disks and pads, no issues, but now the brake pedal is very soft+++. When engine off the pedal firms up OK, with about a 1/2in of travel, and then, when engine started pedal sinks nearly to the floor. When braking, there seems to be an inital slight 'bite' but then pedal sinks, the brake still operate, but its an effort and the pedal firms up when pumped. When retracting the offside rear caliper, it was very stiff, and it seemed to be on the limit of travel, as the pads were well and truely knacked.

unsure as to what has happened, could I have got air into the system, as the pads where that bad, or would it be something else such as a damaged caliper?

I have heard of 'flipped' master cylinder seals, but surely the system wouldnt work at all if this was the case...

give the brakes a bleed see if that helps

agree check the brake fluid level then bleed the brakes

Cheers Guys.

I will bleed the brakes, and see what happens. With the handbrake being OK ( which I forgot to mention sorry), coming on to full effect after 5-6clicks, its got to be something hydraulic I would have thought, and not the piston travel in the calipers, unless the bad califer is not working properly, and its braking on only 1 rear.....

when retracting the pistons did you open the brake fluid resevoir?

Yes, took cap off, and also used proper piston winding tools.

Yes, took cap off, and also used proper piston winding tools.

Hopefully you have just induced air somehow and havent damaged any seals.

So do i..... Worst case the master cylinder seals have flipped, which is a pig of a job... Any ways to flip them back? Once master cylinder out, can i just remove piston and reseat the seals, or is it a rebuilt kit job. Not to fussed on parts as i get them at cost, but would prefer not to have to. Steep learning curve if it is :-(

I wouldnt think so, once they have flipped its a rebuild? have you tried bleeding?

Gonna do that tomorrow, and will let you know the results...

Sorry for late reply guys, wasnt very well last week.....

Got the car up in axle stands today, and had a damn good look at the offside rear caliper. Noticed that the bleed nipple was rounded off, and it was actually leaking fluid as well, hence the spongy pedal. I can oly assume the last people to mess with the rear brakes, (Local garage!!!), rounded off the nipple, and with the piston being at the end of its travel almost this time, pushing it back has been the proverbial straw..... Wasnt alot of fluid leaking, as it wasnt dripping on the floor, but it was all around the nipple and the caliper. Anyhow, changed the caliper over for a new one, and as I had the ezibleed out and the car was on stands, bled all the brakes, to renew the fluid at the same time. jobs a gud un now.

Thanks for all the advice chaps.

good result then mate, cheers for the update