hello there.

Does anyone have a Sieraa haynes manual to hand? I'm trying to find out the diameter of the pistons on the front and rear brake calipers (disc brake rears, 240mm vented disc fronts).

Ultimately I'm trying to work out if i have enough travel on my brake pedal and associated balance bar/mastercylinders.

Cheers
Andy

Fronts were either 54mm or 57mm diameter (depends upon body style and engine options I think) and the rear calipers were 43mm diameter.

brilliant, cheers for that!

My calculations show that I'll have around 1.1mm of caliper piston travel! not sure if that will be enough to operate the Sierra brakes well enough, but a bit of tweaking the linkage and master cylinder diameter should do the trick.

Does anyone know roughly how much the caliper pistons should be displaced by a full swing on the brake pedal? (assuming no disc is fitted?)

Cheers
Andy

Usual running clearance, between pad and disc, is between 0.1-0.5mm.

With two pads that means you will need 0.2-1.0mm of piston travel just to get the pads to touch the disc. Applying force and hence generating torque will reuire perhaps 50% more.

What diameter is the mastercylinder bore? Is is a tandem cylinder (two pistons in the same bore)?

I'm using a two seperate master cylinders, one powering the front braking circuit, and one to the rears. I've got an adjustable bias bar to tune the distribution of braking front to rear.

the cylinders are 0.7" diameter, and are made by Wilwood (their compact remote resevoir ones). I was led to beleive these would be more than adequate for use with Sierra calipers, so maybe I've worked something out wrong somewhere!

Cheers
Andy