Replace brake proportioning valves in pairs. Use only brake proportioning valves with the same lead and the same switch-over pressure. Identification is given on the valve housing (e.g. 3/30) 3 = lead / 30 = switch-over pressure.
 Remove, Disconnect Unscrew cover from brake fluid reservoir. Top up brake fluid reservoir to "MAX" and close with commercially available dummy screw cap. Remove brake lines from brake proportioning valve at vehicle underbody (arrows) - in doing so counterhold valve with open-ended spanner.
 Install, Connect Insert brake proportioning valve - fasten, in doing so counterhold valve. Install brake line at brake proportioning valve - tightening torque 16 Nm / 12 lbf. ft.
 Inspect Bleed brake system and check for leaks - see operation "Brake System, Bleed and Check for Leaks". | 
Important! 