Defender clutch failure
SOME faults on Land Rovers are so common and well-known that you can diagnose them over the telephone before the customer is halfway through describing the symptoms. The owner of a 1992 Defender rang me. The clutch wouldn’t disengage, and the clutch pedal was absolutely solid. Most Land Rovers with the LT77 or R380 gearbox have a pressed steel clutch fork pivoting on a solid ball inside the bellhousing.
The metal in the fork is stretched thin where the recess is pressed into it for the ball, creating a weak spot: it is quite common for the ball to punch straight through the fork, allowing the fork to be pressed firmly against the back of the bellhousing and locking the clutch pedal.
The owner surprised me by driving the vehicle to my workshop, a distance of about 15 miles from his home. Driving a vehicle with no clutch is possible: once you are moving (engage first gear then operate the starter until the engine fires and the vehicle starts to pick up speed) you can change gear by carefully matching revs to road speed. It takes a certain amount of mechanical sympathy, requires almost telepathic anticipation of hazards ahead to avoid having to come to a halt, and probably contravenes some law or other. I last did it in 1993 when I was driving an ancient Ford Escort from Oxford to Lincoln and lost the clutch release somewhere near Towcester. I managed to get through Northampton in rush hour and was just starting to think I might make it home when I came to a long queue of stationary traffic on an uphill stretch of road near Thrapston, and that was that.
With the engine and gearbox separated on this Defender I had a surprise. The clutch fork was perfect: not so the release bearing. The standard item has a metal bearing in a plastic housing and the bearing had overheated, melted the housing and disintegrated.
The clutch slave cylinder was the wrong type which further limited the available pushrod travel, so the end of the fork bottomed out on the bellhousing before it could push the remains of the release bearing against the clutch cover.
A new clutch kit (along with a strengthened fork to prevent the pivot ball punching through it in future) soon had this Defender back on the road.
These plastic-bodied release bearings don’t much like being put under load for long periods. So if you are in the habit of sitting in traffic with first gear engaged and your foot on the clutch, don’t.
Knock it into neutral and take your foot off the clutch whenever you can. All-metal release bearings are available but they are not cheap: the standard bearings are fine if treated with a little sympathy.