Hi all, as per title really!

My RS1800 runs full ST170 Engine/box and Brakes. Due to space issues I had to use a Rally Design universal balance-bar pedal-box and AP-Lockheed remote 2.3:1 servos.

My car has now passed its MOT But I still would like a bit less pedal travel, you have to press it quite far down before the brakes do anything but they ARE progressive AND powerful when you do finally get there...

I currently use a 0.625" Master cylinder on the fronts and a 0.700" on the back and both my remote servos use a 0.625 reaction cylinder.

I have a normal focus haynes manual here which says my rear calipers are 34mm piston diameter and normal focus front calipers are 54mm, Does anyone here know the Caliper piston diameter of the st170 fronts??

If i find this out I'll be able to change my master cylinder piston size to suit.

Thanks for the anticipated help!

 

54mm according to my catalogue.

Thats why I still have ERST calipers as they have 59.9mm ones.

Are you sure you have the balance bar correctly set ?

 

Yeah I set it up in my friend's garage on a roller-brake tester, seems strange that the ST calipers are the same piston diameter as the "normal" focus ones as the ST ones are physically larger overall

Ah well, I guess I could always try going to a 0.7" front M/C and a 0.75" rear M/C and see what that does

Either way the car still stops well, it's just my other car is a focus TDCi so I'm used to new "production car" brakes I suppose...

 

Just try swapping them round first.

You may have to swing the balance bar over a bit more to take some more pressure off the rears.

What pads are you running ?

 

Yeah may try that tomorrow, just Rally Design said the wider M/C should drive the rears, something to do with hydraulic power/pressure calculations that bigger cylinders give LESS pedal travel and LESS power, smaller M/C's give MORE pedal travel but MORE power. I know that sounds backwards but that's what they say!

Won't do any harm to try though...

Using mintex ST170 front pads at the moment as I drive predominantly on our hectic roads so wanted some "instant bite" rather than fancy fast-road pads that need warming up!

 

It's not backwards, it's just logical if you think of it.

 

Must be just me that's backwards then!