Q. My Series III 88in has been developing a juddery clutch. It’s most noticeable when taking up drive in first gear, just after the clutch bites (the biting point is near the top of the pedal). The clutch was replaced six years and 6000 miles ago. Gary Long, Cambridgeshire
A. Given that your clutch has operated correctly for the last six years we can probably rule out defective or incorrectly-fitted parts. And after 6000 miles, nothing should be significantly worn.
It is possible the clutch assembly has suffered broken springs, though it will, of course, need to be dismantled to check that. Oil contamination of the friction plate is a typical cause of clutch judder, and this can come from a failed crankshaft rear oil seal or from the gearbox’s input shaft seal. Again, it’s a dismantling job to find out and, if there is oil on the clutch, you’ll need to replace the complete assembly as well as the offending oil seal. If you take this investigative route, though, you’ll be able to check the clutch release bearing and its mechanism, as well as the clutch cover bolts and flywheel bolts.
It’s also worth checking the flywheel run-out while the clutch assembly is removed – it shouldn’t exceed 0.05mm. Check the spigot bearing in the flywheel and the condition of the gearbox shaft end.
But before going to all that trouble, check the propshaft flange bolts are tight. If so, disconnect the prop shafts to check their universal joints. Looseness here can give the same effect as clutch judder. It’s also worth checking your transmission brake is not binding by confirming the vehicle rolls freely in neutral (that’s assuming all the wheel brakes are free when released).
Other possibilities are a loose flywheel bolt or the flywheel running slightly out of true, but the latter is unlikely unless the vehicle has recently been put through some aggressive torment. A worn crankshaft thrust bearing can allow sufficient axial movement of the crankshaft to cause judder, but this would be expected only on a high-mileage engine, and usually when the engine is hot.
As you suggest, it’s also worth checking the transmission mountings to see if they have split, gone soft or are loose. Use a stout lever to test them.