Posted on March 6, 2022 by Jack BobCat 753 – FRONT AUXILIARY HYDRAULIC COUPLER BLOCK – Removal and Installation (S/N 515842310 & Above) Disconnect the auxiliary tubelines (Item 1) and drain tubeline (Item 2) [Figure 20-121-1] from the coupler block. Remove the two mounting bolts (Item 3) [Figure 20-121-1].