adjacent to the brake piston filled with a hydraulic fluid specifically formulated for meeting certain expected operating conditions in the wheel brakes the second chamber is connected to the hydraulic lines and is filled with a second fluid specially formulated for meeting certain other different expected operating conditions in the lines and master cylinder application_number US 63281684 A description the embodiment of the invention as shown in fig1 has a spot type fixed caliper disc brake being designated in its entirety by reference numeral 1 the disc brake has a flange body 2 mounted toward the inner side of thevehicle and a cover body 3 arranged in a wheel dish 4 toward the outside relative to the vehicle the part 5 of the wheel rim which accommodates the tire is also outlined the disc brake 1 is secured to the vehicle axle e g to the wheel body with the aid of at least two mounting eyes 6 only one of which being shownin the drawings this construction is generally known and therefore not shown in detail again in a conventional manner a brake disc 7 is secured to the wheel hub by means of screw bolts 8 so that the brake disc rotates synchronously with the rim 4 and 5 that is to say with the wheel in a fixed caliper disc brake 1 of the type shown in the drawing wheel brake cylinders 9 and 10 with the relevant pistons 11 and 12 are containedboth in the flange body and in the cover body 2 and 3.