1962 CLUTCH NOISE


Q:

I have an early 1962 Corvette. I replaced the clutch return spring with the correct, much heavier

spring. Now the linkage Is making strange noises. At first I thought it might be the bushing, but the noise appears to be in the cross shaft. Can the cross shaft be lubricated without removing it? Any thoughts or suggestions would be appreciated.


A:

The only way to lubricate the bell crankshaft pivot points is to try to shoot some oil into the open

ends of the bell crank tube. There were originally two felt seals, one at each end of the tube, to keep dirt and water out. If they are still in place, it will be difficult to get oil to go in there. You could drill a hole into the center of the tube and install a grease fitting in the hole. (they make grease fittings with a standard 1/4" - 28 thread size) Then, with a grease gun you could force grease into the hollow tube, and it would come out of the ends where he pivot balls are located, greasing

those points thoroughly. This would be a modification to the original configuration of the bell crank. If the car is going to be judged in an NCRS type of competition, that modification would get you a point deduction, so give it some thought before making that change.


I find that the pivot balls, which are hidden inside the bell crank tube, are often worn badly. When

I disassemble the bell crank parts, I often find that the pivot balls are completely worn off on one side. This allows the shaft to twist, so it is no longer operating on the same axis of rotation. This can cause binding, which can easily lead to noises. Remember, if the shaft is twisted, the arms will not swing in their original arc. Therefore, the pushrods attached to those arms may actually hit the arms or bind in their pivot holes when they move. Noises could be caused by that resulting misalignment. Because the two pivot balls are hidden inside the tube and not visible, and because

the heavy spring puts so much  pressure on the bell crank, it is almost impossible to check for wear

in the two bell crank pivot balls. If the spring was removed, one could grab the bell crank and twist it to determine If there was wear In the pivot balls. It should not twist very much at all. This Is probably the best idea, but it takes some doing to remove that heavy duty spring.  Speaking of the holes in the levers that the pushrods fit into. If one of those holes has worn from round to oval, the pushrod may be forced to one end of the oval when the linkage is at rest; and when the linkage is placed into operation, the pushrod may pop from one end of the oval hole to the other end,

which causes a noise. This condition is often found at the hole in the clutch pedal bracket, on the upper end of the long rod that comes through the firewall. Look for wear on the ends of both pushrods; the long one that goes through the firewall, and the short one that goes to the throw out fork. Check the ends of the rods and check the holes that they fit into.


Additionally, it is important to have the clutch adjusted properly. Remember that there needs to be a small amount of play between the throw out bearing and the fingers of the  clutch pressure plate when the clutch pedal is in the released position.  This play will assure that the throw out bearing is fully stopped when the clutch is not being used. If there is no play in that adjustment,  the throw out bearing will turn constantly which will wear it out very soon. That bearing is only designed for intermittent use. If it is constantly turning, the lubricating grease will liquefy due to heat, and run out of the bearing leading to premature failure. I sometimes hear noise coming from a clutch that has

been adjusted too tightly. As a matter of fact, I just repaired one like that two days ago. All it needed was a proper adjustment, and the noise went away and the clutch works fine. Good Luck.