4-43. AIR RESERVOIR REPLACEMENT (Con't).
(10) Connect air lines to ratio relay valve, if front air reservoir was removed (see paragraph 4-42).
(12) Fully pressurize semitrailer air system (see TM 9-2320-273-10 or TM 9-2320-284-10).
(13) Apply a soap solution to check for leaks at all air reservoir fittings and air lines.