HELP - Brake Master Cylinder Resovior (Page 1/1) michfiero1 SEP 22, 12:14 PM Hi All, I can't get the new resovoir to seat. Visually it looks identical to the old and I have pushed hard.but no luck. Now what? Thanks! michfiero1 SEP 23, 06:01 AM Success. It seems the key is to remove the seals from the new reservoir, install them in the master cylinder and then install the reservoir itself. Lube the seals and the stem of the reservoir with a little brake fluid and it should go. Be sure the new reservoir seats all the way down (check the old one first for reference).