Alright got a little issue. I've redone all my brakes except the master cylinder that i just cleaned up. When I pump the brakes it builds up pressure but as soon as I release my foot off the break I can see all the brake fluid fill back into the reservoir and I loose pressure again. It comes back in through a second drilled whole never saw this on a master cylinder before usually just has the one. Did I just reassemble it wrong? or should I weld this hole shut? And thankyou for any help.
-Mitch