I am working on a 1983 Ford F150. I have a problem with the master cylinder leaking at the power booster. I have installed a master cylinder, still leaked, recently had a new power booster and master cylinder installed, it still is leaking. The only item I have not changed are the brake lines, is it possible it is leaking at the lines where they connect to the master cylinder and running down the master cylinder and then down the front of the booster?

Thanks for the help.

 

Yes it is possible for the cylinder leaking at the lines I'm assuming you bled all the lines after installing the new cylinder and booster

 

Clean of lines and master cylinder with spray brake cleaner, have someone press and hold on brakes. Using your hand check for leaks, repair where leaking. Brake fluid will not hurt your skin, just don't touch your eyes.