Most of these block manifolds seal by compressing the o-ring into pre-determined groove dimensions w/ manifold/compressor faces that butt together; i.e. you don't determine the squeeze pressure by tightness of the bolt. Once snug, the oring will get all the compression possible. I would guess one of two possibilities; either you tightened the bolt w/ orings out of position or the orings are the wrong size; too small allowing bypass. This type of arrangement requires the correct oring or no seal for sure.

Solution is to insure you have the correct orings. You matched to orings that failed, so you may have simply repeated someone elses earlier mistake. The orings should fit snugly in the grooves and be thicker than the combined depths of the separate grooves to allow compression to occur. Orings work well but can only leak w/ insufficient squeeze.

good luck

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