What master cylinder ?
Discussion
According to the Alternative Parts list here
http://www.alexjudd.com/cerbera/parts/#Brake%20mas...
It's Fiesta Mk 2 XR2 or 1.6 Ghia.
I think that the Mk3 Fiesta is the same (note sure but I know that fits the S-Series with exactly the same servo)
As it says on that site, there are two bore diameters, make sure you get the bigger one.
http://www.alexjudd.com/cerbera/parts/#Brake%20mas...
It's Fiesta Mk 2 XR2 or 1.6 Ghia.
I think that the Mk3 Fiesta is the same (note sure but I know that fits the S-Series with exactly the same servo)
As it says on that site, there are two bore diameters, make sure you get the bigger one.
GT6k said:
Good to see you got home OK yesterday Brummie and thanks for the loan of the slicks. I could have done with floats and oars on the way home.
No Problem, was good to go out in an original one as a point of reference! 
Thanks for the advice guys, i am going to get a new one fitted this week before something nasty happens.
A smaller master cylinder will give a longer pedal but more power, does the 4.5 run the smaller one then?
It would give more feel theoretically, as the 4.5 runs bigger discs and i run bigger still this might be an interesting experiment?
The stock 4.5 was good, alot more friendly than mine to drive i suspect, but mine is so fast its terrifying, especially if you are not used to it. I gave Dobbie on here a blast in mine and it was faster than he thought it was going to be, and he thought his shoulders might be bruised from the harness's as the brakes are so fierce, but after 3 laps i suspect the master cylinder has finally given up the ghost, as it was taking 5 or 6 pumps to get any brakes, at every corner!!
It would give more feel theoretically, as the 4.5 runs bigger discs and i run bigger still this might be an interesting experiment?
The stock 4.5 was good, alot more friendly than mine to drive i suspect, but mine is so fast its terrifying, especially if you are not used to it. I gave Dobbie on here a blast in mine and it was faster than he thought it was going to be, and he thought his shoulders might be bruised from the harness's as the brakes are so fierce, but after 3 laps i suspect the master cylinder has finally given up the ghost, as it was taking 5 or 6 pumps to get any brakes, at every corner!!
Well this is what I was thinking. Mine has behaved how Brummie describes for ages. I put it down to boiling fluid but even fresh CL fluid still did the same.
Changed my braking method (was being a girl and braking early and gently vs late and hard) allowing plenty of cool down time between corners but it still does it.
But perhaps I have a failing master cylinder.... Although my experience of a failing master is as you describe, always spongy and requires pumping unless you press hard and fast as this fires the seals out straight away.
Changed my braking method (was being a girl and braking early and gently vs late and hard) allowing plenty of cool down time between corners but it still does it.
But perhaps I have a failing master cylinder.... Although my experience of a failing master is as you describe, always spongy and requires pumping unless you press hard and fast as this fires the seals out straight away.
Pads are new and the best! Fluid is new, brake lines are new...
This has been a problem all year and getting steadily worse, funny thing is yesterday i got around 6 laps before failure, i then bled through with brand new fluid and it lasted 3 laps, and the worst failure yet, every corner even when coasting back to the pits needed 5-6 pumps.
Pedal comes back after a few minutes, i have even heat gunned the calipers at failure and fronts are 255C rears are 190C, fluid boils at 325C.
And 3 laps is no where near enough to boil them
I am thinking that bleeding them took even more edge off the seal hence quicker failure than before. You just cant replicate those conditions on road.
Job looks a complete pig to do, but this is THE last thing it can be.
This has been a problem all year and getting steadily worse, funny thing is yesterday i got around 6 laps before failure, i then bled through with brand new fluid and it lasted 3 laps, and the worst failure yet, every corner even when coasting back to the pits needed 5-6 pumps.
Pedal comes back after a few minutes, i have even heat gunned the calipers at failure and fronts are 255C rears are 190C, fluid boils at 325C.
And 3 laps is no where near enough to boil them
I am thinking that bleeding them took even more edge off the seal hence quicker failure than before. You just cant replicate those conditions on road.
Job looks a complete pig to do, but this is THE last thing it can be.
Please keep me posted on this Brummie as this is EXACTLY the problem I have ad for 2-3 years now. It has spoilt many a trackday only being able to get 3-4 laps before all confidence in having anything under your right foot disappears!
However, if it is the master cylinder I'm not going to be happy!!
However, if it is the master cylinder I'm not going to be happy!!
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