Fluid must begin to escape by the free opening «b» when pressure rises between 70 and 90 bars (995 and 1280 psi) Checking the brake control valve. By means of plugs, block : - Both openings «a» and «b» of the feed pipes for front and rear suspension. Connect the brake feed pipe to the end piece «d» of the three-way union. Start the engine. Tighten the pressure regulator bleed screw.