I just replaced my ace pump on a 1999 discovery series II and I need to know the best way to bleed the system if needed the bearings blew up on the pump and got a new one don't know if the lines or full or have air need to know how to bleed if needed.

Ideally hawkeye/nanocom or test book,I've read though that a quiet road and lots of weaving side to side gets the job done,keep a close eye on fluid level though,don't let it get too low
Welcome to the forum and don't forget to post in the intro section before you get mauled !!

Ive just had to look up what an ace pump is


jacking the chassis up until the wheel is off the floor a corner at a time may help ,while running and checking level

wind pulley over by hand till pump is primed before putting belt on and starting engine

As jamesmartin says ^^^, if you dont do this it can take a long time to self prime and the pump will probably already be damaged by the time it does. Once pump primed and belt re-fitted, circulating parts of system will self prime quickly withengine running.
After takin a spin and creating some roll to get system working, this will put some pressure in lines. Once back home there will still be some residual pressure and you could then carefully slack banjo connections at rams to get any air out of the stagnant lengths of pipe but I would only do this if youve replaced these pipes and you know there is air in them. Wear goggles mind.
As HenryD says doing it electronically is the official method as per the book but I cant see for the life of me how this will prime the stagnant legs without getting under there and backing off the ram connections.

listen to james martin as on motors he is never wrong and has a great knowledge plus runs a d2. So he would not tell you something unless he is 100%