Was hoping someone could help with a braking issue (front) on my 1991 AT RD04. I've rebuilt the calipers and fitted the master cylinder repair kit, bled the brakes and fitted new pads but there's absolutely no build up of pressure at the brake lever. A couple of times I've managed a very slight build up but not enough to prevent me from rolling the bike forward and it hasn't lasted. I'm thinking my next move should be either a new master cylinder or braided hose lines. The bike has only done 21,000 miles but has been sitting for several years. Thanks in advance.