Marc sierra

iTrader: (1)

Are there any differences between the cosworth 2wd and standard sierra 2wd ABS master cylinders?

My car has a standard Sierra 2wd ABS master cylinder. It used to have the 260 mm front discs and 253 mm rear discs and with that setup everything was fine. I then upgraded to 283 mm front discs with the Cosworth 4x4 single pot front calipers and 273 mm rear discs. All still fine. Now I changed the 4x4 cosworth single pot calipers for the 2wd cosworth 4 pot calipers and the pedal travel has become very large.

I first thought the brakes were not bled properly, but that wasn't the case. I then figured the MC was no longer OK, so I changed that one for another one from a standard Sierra/Granada, but the result is still the same. Depending on how much grip the tyres have I can even hit the bottom of the pedal in some cases. When there is slightly less grip the ABS kicks in just before the pedal hits the end stop.

Does the 2wd cosworth have a bigger master cylinder due to the 4 pistons? The surface of 2 pistons of the 4 pots is slightly less than the single pots on the 4x4, but maybe the travel of the pistons is bigger because they are on both sides of the disc? But if this is the case I guess it should also be a problem to use a cosworth 4x4 master cylinder on a 2wd cosworth.

Does anybody know??

Thanasis

iTrader: (3)

there is one difference from 4wd to 2wd 4 pots calipers due more pistons so the pedal pressuse is normal to change,but do you check the 2wd calipers if the pistons works free?

Marc sierra

iTrader: (1)

The 4 pot calipers are refurbished and have new seals, so they are working perfectly.

I did check the finis codes for the ABS master cylinders and 3 LHD types are listed, standard, cosworth 4x4 and cosworth 2wd. But that isn't really full proof for me as Ford sometimes gives parts different finis codes even if the parts are actually the same.