Lancashire posted a score of 140 and 298 for 7, with Wells scoring 78* and Bohannon hitting 60. They have taken the lead against Somerset, who were bowled out for 146, with Bailey taking 4 wickets for 36 runs and Balderson taking 4 wickets for 50 runs. Lancashire now leads by 292 runs.
Lancashire's batters made title-chasing Somerset work for every wicket on the second day of the Vitality County Championship match at Old Trafford and had built a formidable 292-run lead at close of play.
Josh Bohannon's 60 and Luke Wells' unbeaten 78 enabled the home side to finish on 298 for 7 in their second innings of a match both sides desperately need to win, Lancashire to preserve their hopes of avoiding relegation, Surrey to stay in touch with Surrey at the top of the table.
The difference between the first day's play and the second was immediately apparent during a morning session in which Lancashire scored 90 runs in 27 overs for the loss of only two wickets.
On a pitch that had dried out and lost much of the greenness, bowlers had to work harder for their successes and the only batsman dismissed in the first hour was the nightwatchman, Will Williams, who was leg-before wicket to Craig Overton for 7 in the third over of the morning.
Harry Singh then added 85 for the third wicket with Bohannon, who batted beautifully to make 60 off 76 balls. However, it was indicative of the problems Bohannon has encountered this season that his half-century was only his fourth innings over fifty in 22 Championship innings.
of which diminished Somerset's joy in the penultimate over before lunch when Bohannon tried to pull a ball from Kasey Aldridge but only succeeded in diverting it via the toe of the bat to Tom Abell in the gully.
On the resumption, Singh and Rocky Flintoff defied Lewis Gregory's bowlers for 50 minutes until Singh thin-edged a catch to James Rew off Brett Randell to give the New Zealander his first wicket for Somerset.
Singh had faced 142 balls during his 260-minute innings of 30 but his patient resistance was not copied by Matty Hurst, who hit three breezy fours in 19 runs before attempting to drive Randell and nicking a catch to Overton at second slip.
In the next over, Flintoff was bowled by Jack Leach's arm-ball for 27 but Well and George Bell saw their side through to 214 for 6 at tea, when Lancashire's lead was 208. And on the resumption, Wells and Bell extended their seventh-wicket stand to 83 before Bell was bowled for 23 when trying to pull a ball from Gregory that kept low.
Wells shifted down into the middle order for this match, having struggled in his usual opening role in recent weeks. Batting as low as No. 7 on account of Williams' deployment as a nightwatchman, he went on to emulate Bohannon's feat in passing fifty for only the fourth time this season but his strokeplay was impressive, most noticeably when he hit three off-side boundaries in one over from Gregory.
And the day ended with Lancashire in the ascendant. Wells was unbeaten on 78 and Somerset's fielders appeared aggrieved that George Balderson had not been adjudged run out on 5 when apparently run out by Overton's throw from slip. The visitors had earlier been penalised five runs for fake fielding.