It took 11 minutes for any real chance to materialise when after Chris Cornes' cross was headed out to the feet of Danny Sonner, the veteran ballooned a shot over the bar from 20 yards.
The visitors got their first look at goal after Ben Muirhead's promising forward run was greedily wasted by the midfielder when he attempted to chip Mark Goodlad from range without success.
Sonner tried his luck again in the 32nd minute but still couldn't find the target when his shot was parried at full stretch by the towering Donovan Ricketts for a corner.
Lee Crooks also fancied his chances from range and almost gifted his side the lead when his 30-yard shot was spilled but the goalkeeper recovered in time to deny the arriving Steve Claridge.
The Bantams pushed again seconds before the break but still with no reward when Claridge's cross was chested down by Bobby Petta inside the area but he couldn't find the power to steer it past Goodlad.
The home side almost fluked a goal six minutes into the second half when Gary Mulligan's ball across the face of goal took a touch from the boot of Mark Bower but luckily for the defender the ball trickled wide.
George Pilkington got himself involved in the Vale attack with a rare shot, sending a 25-yard strike towards goal that had to be touched over the bar by Ricketts.
The Bantams finally broke the stalemate after 64 minutes when Claridge seized upon Muirhead's through ball, shaking off the nearing defenders and hammering the ball into the net from six yards.
The Valiants continued to search for a goal but as before they struggled to find the cutting edge.
Mulligan came closest when he re-directed Chris Birchall's cross towards goal only to find the goalkeeper's arms.