Abstract: Method and apparatus for coating catalytic converter substrates with an exact amount of a precious metal. In the course of operation of the apparatus, a hollow substrate to be treated having opposed open ends is transferred from a starting location such that one end is lowered into a dip pan into which has been introduced a predetermined amount of slurry material containing the precious metal. With the one end immersed in the slurry, a vacuum placed on the other end of the substrate draws up the entire charge of slurry from the dip pan to coat the lower portion of the substrate. Thereafter, the substrate is raised from the dip pan. The vacuum continues to operate to cause the coating to be evenly distributed on all the interior surfaces of the substrate. Then the substrate is rotated and again lowered so that the other end is immersed in another predetermined charge of the slurry and the process is repeated. Thereupon, the substrate is again raised from the dip pan.