If the pump arm pivot holes in the pump tube are not de-burred, the piston cup/valve Oring may have been cut or nicked when you removed/re-installed them. I had that happen a few times .
Thanks for the input. my pump cup did have a few nicks. Sanded down all the funky burrs on the inside...new cup & Fixed !
Quote from: happymecanic on August 14, 2022, 09:58:55 PMIf the pump arm pivot holes in the pump tube are not de-burred, the piston cup/valve Oring may have been cut or nicked when you removed/re-installed them. I had that happen a few times .This right here. I had the same issue recently when repeatedly taking apart my 1377.To the OP, take some fine sandpaper and sand down the interior of the pump tube to make sure there are no metal burrs sticking out that will damage your o-rings upon reinstallation. I had some burrs show up thanks to my hammering the pivot pin in & out. I cleaned up the burrs, replaced the damaged o-ring, and that seemed to have solved my problem. The o-ring damage may not be clearly visible, so even a visual inspection of the o-ring may not be sufficient. I suggest you get a supply of the correctly sized o-rings for the 1377 so that you can have then handy to swap in & out as needed.Turby
Those pivot hole burrs did my 1st 1377:
Thanks.I had it machined.