100-4 Clutch Linkage Wear
By Norman Nock
Originally published in the Austin-Healey Magazine, February 1996
The working of the clutch linkage of a100-4 is very trouble-free when inspected and maintained regularly. But if you have driven your car for thousands of miles and forgotten about the clutch mechanism, one day, without warning, you could push down the clutch pedal down and hear a BANG. Your clutch pedal has gone all the way to the floor and will not return.
Another scenario: You are having trouble engaging first or reverse without grinding the gears. "Aha," you say. "I need as new clutch." So out comes the transmission and in goes a new clutch. (Note: don't use a rebuilt clutch--it could cause a judder.) You road test the car and all is fine for a while. Then the same problem has returned--grinding into first or reverse. Now what?
Your problems could be caused by wear in the clutch linkage. Figure 1 shows the just where this could occur:
A: The clutch arm on the side of the housing cracks and causes free play to increase.
B: The clutch adjusting rod: This rod will wear to the point of breaking, giving you no clutch pedal operation. The pedal is on the floor. The rod will bend or the adjusting rod threads become worn.
C: Clutch rod: This is the usual cause of losing all operation and causing the clutch pedal to stay on the floor. This rod wears to the point of going bang when it breaks. The original rod is weak and should be replaced by a new, stronger rod that is square.
D: This arm wears. It can be repaired by brazing the holes closed and re-drilling them. The bushing is available. This arm and the clutch arm (F) have long been unavailable. Replacements are available now.
E: The shaft that goes through the chassis will wear. If you need to replace it, a new shaft is available on your own car. Check the right-hand chassis rail for the shaft used by right-hand drive cars.
F: This arm can wear the same way as the arm described in D above. It can be repaired the same way.
G: The grease fitting on the end of this shaft. If not lubricated the clutch and brake pedal will become very stiff, causing the pedal not to return to its static position. The bush that goes through the chassis rail is available new.
H: Return spring plate: This small plate screws down to the clutch housing. If it is missing, you will have no clutch return spring. Without this spring, the clutch throw-out bearing will rest on the clutch plate, and could cause wear on the bearing.
I: A special washer fits here to keep the cross shaft from moving sideways,
New parts to rebuild your clutch linkage are available in kits.
Not what you were looking for? Don't forget you can check our back issues using the AHCUSA Magazine Index.