Jenson Button's McLaren suffered engine failure on the last day of testing
Sebastian Vettel set a 1m37.468s lap in his Red Bull, the 9th fastest lap out of the 12 drivers testing
Marussia had clocked up a total of 61 laps at the end of the fourth day's testing
Kami Kobayashi suffered clutch issues on day four
Lewis Hamilton set the quickest time, at 1m33.278s; the Mercedes completed 70 laps in testing
Adrian Sutil and Esteban Gutierrez shared the final day's testing times
Red Bull continued to have difficulties throughout the final day
Fernando Alonso set a time of 1m34.280s in his Ferrari, making him third fastest overall
A Caterham goes wheel-to-wheel with a Force India during the final day of testing
Vettel clocked up 77 laps during the fourth day of testing
Marussia's Max Chilton set the seventh-fastest time of the day, with a lap time of 1m36.835s
Sauber's Esteban Gutierrez clocked a fastest time of 1m37.303, placing him 8th overall
Red Bull's Sebastian Vettel suffered from a front-end issue with his car in the morning
Kobayashi racked up 106 laps, despite some mechanical issues
Ferrari's F14 T suffered a failure during testing, but still managed to set the third fastest time of the day
Lewis Hamilton had pushed his Mercedes to the top of the leaderboard by the end of the day
Mercedes did suffer from a gearbox issue early in the morning on day four, but managed to resolve the problem
Valtteri Bottas, driving the Williams, placed second overall at the end of the final day's testing
Ferrari's Fernando Alonso set a fastest time of 1m34.280s
Sauber's Adrian Sutil completed 91 laps and set a fastest time of 1m36.467
Many of the teams, including Red Bull, McLaren and Lotus, suffered from significant issues during the final day of testing
Williams driver Felipe Massa was fastest on day three, completing 99 laps of the Bahrain circuit
Massa managed a best time of 1m33.258s on day three
Jules Bianchi's Marussia put in 78 laps overall on the third day of testing
Daniil Kvyat completed 81 laps in his Toro Rosso on day three
Kvyat put in a best time of 1m36.113s on the third day of testing
Daniil Kvyat placed fifth overall in the timings standings on the penultimate day of testing
Rosberg completed 103 laps on day three, despite losing out on much of the morning session
Rosberg briefly took the timings lead from Massa late in the third day of testing
The third day marked Kimi Raikkonen's last day of testing in the Ferrari
Kimi Raikkonen could only manage the sixth fastest time in the morning session on day three
Nico Hulkenberg was second fastest for Force India on the morning of day three, only 0.776sec shy of pace-setter Felipe Massa
Romain Grosjean gets it wrong under braking, and only managed 14 laps in a slow morning session on day three
Nico Rosberg - for once - was not the fastest out there in his Mercedes on the morning of day three
Daniil Kvyat showed promising pace in the Toro Rosso, unlike sister team Red Bull, on the third day
Word champion Sebastian Vettel's car broke down on his installation lap on the third day of testing
New McLaren boss Eric Boullier and technical chief Sam Michael have Kevin Magnussen driving for the third day
Marcus Ericsson gets ready in his Caterham before setting the seventh fastest time of the morning of the third day's testing
Red Bull top brass discuss the team's continued testing woes
Day 2: Marcus Ericsson locks up his Caterham's front wheel
Day 2: Jean-Eric Vergne was just over four seconds behind Perez
Day 2: Jenson Button was the victim of a technical glitch which left his McLaren stranded on track
Day 2: Alonso rode more laps than any other driver
Day 2: Maldonado's day was cut short after his Lotus caught fire
Day 2: Gutierrez was 4.4sec off the fastest
Day 2: Sergio Perez topped the time sheets for the second day in succession
Day 2: Hamilton parked his Mercedes in the gravel, prompting a red flag
Day 2: Massa was just over a second down on Perez and finished the session fourth quickest
Day 2: Button recorded the fifth quickest time
Day 2: Alonso locks a wheel during an otherwise successful session
Day 2: Jules Bianchi enjoyed Marussia's most productive day of pre-season so far
Lewis Hamilton has set the fastest lap time on the final day of testing at Bahrain, after completing 70 laps of the circuit.
His Mercedes-Benz, which took lead position with a 1m33.278s lap, was the quickest out of a total of 12 cars undergoing testing.
Despite suffering a gearbox problem in the morning, he successfully returned to the track to secure the top position.
Problems with the dramatically different 2014-season cars are still rife, however, and Lotus, McLaren and Force India all experienced engine failures.
Red Bull suffered from further issues too, with a technical issue causing driver Sebastian Vettel to lose control at the end of the morning's session. Kamui Kobayashi also had problems, with a damaged clutch bringing his car to a stop.
Williams' Valtteri Bottas set the second-fastest time of the day, a lap of 1m33.987s, followed by Ferrari's Fernando Alonso at 1m34.280s.
Previously, Felipe Massa had set the fastest time on the penultimate day of pre-season Formula 1 testing in Bahrain.
The Williams driver set the pace during the morning session, eventually putting in a best time of 1m33.258s over 99 laps. The day was again overshadowed, however, by the continued woes of world champion team Red Bull.
Sebastian Vettel broke down halfway into his installation lap, and, upon his recovery to the pitlane, Red Bull erected screens in front of their garage to keep prying eyes away as they seeked to resolve their latest issues. Both Sauber and Lotus also suffered technical problems today.
Elsewhere, Ferrari's Kimi Raikkonen had his final day at the wheel of his new car before the season's first race in Melbourne, while Nico Rosberg lost out on much of the morning session due to an engine change. He went on to complete 103 laps in total this afternoon, and sits second in the timing standings.
Bahrain is the final stop on the F1 testing calendar before the season begins next month. All 11 teams are scheduled to be in action over the course of the eight-day test session.
While some teams found the first pre-season test in Jerez, Spain, helpful, others struggled to come to grips with the sport's new rule changes. Chief among them is the move to adopt new 1.6-litre turbocharged V6 engines in place of the older V8 units. The engines use a new hybrid energy recovery system which harvests heat energy from the turbocharger as well as kinetic energy from the brakes.
Elsewhere and the design of the 2014 cars has changed to meet the latest crash-test safety regulations. Several teams have implemented the changes in different ways, with Ferrari opting for a flat snout approach, while Lotus has gone with a split-prong design.
Finally, one of the most contentious changes to F1 this year sees double points awarded at the last race. The move is designed to increase competition, and to stop a single team or driver running away with the championship well before the season is over.
Take a look through the picture gallery above to see all the latest pictures from the Bahrain pre-season testing session, and read our ten reasons to get excited about the return of Formula One here.
Additional reporting by Lewis Kingston, 2 March 2014