Gear selection

Q: My son-in-law has a 2012 Astra 1.6 with a F17 gearbox and is having intermittent trouble with the gears in slow-moving traffic. On such occasions, he has difficulty getting it in or out of gear. It’s not losing any fluid, so could the master cylinder be playing up or is there another problem? John Evans

A: If the problem is hydraulic, then pumping the clutch pedal should make the selection of gears easier. Normally, a faulty or leaking clutch master cylinder will show signs of weeping around the input pushrod. By looking up under the clutch pedal, you should be able to see the rubber gaiter where the pushrod enters the master cylinder. Even though the reservoir level may not appear to be dropping, the slightest sign of weeping will indicate the seal is leaking, drawing in air rather than releasing the fluid. Any sign of clutch fluid around the gaiter would suggest the clutch master cylinder is failing and needs replacing.

If no signs of fluid are visible, the problem may be that the clutch has worn. When this occurs, the slave cylinder needs to travel further to release the clutch. This will then throw out further than it is designed to. When this occurs, the slave cylinder can draw in air, causing further problems.