C2 throwout bearing/L79

[John Thomas]

I continue to have questions about my throw out bearing. Installed a new throw out bearing in my L79 driver. Bearing is 1 1/4" long. After a 30 min. idle time, when I pressed in the clutch I would get a noise sounding like it was coming from the throw out bearing. It was not chatter, but rather a clicking similar to a skate wheel, that I attributed to the throw out bearing. Adjusted the bearing 7 ways from sun down. This helped but didn't completely solve noise problem. I removed the "new" throw out bearing and it appeared to be fine. My only observation was that the "channel" of the bearing that the fork slides into has a single "cam" lobe appearance. The original does not.

New bearing, Timken this time with same lobe looking arrangement, same results. Is this cam looking arrangement going to work with my clutch? Do I need to find the original design with a smooth circular channel? Does this cam lobe fit within the fork fingers or outside the fingers? Where is this noise coming from? I'm too old to be doing this every weekend. Any suggestions would be appreciated, and don't worry about hurting my feelings. Obviously I am not finding the problem.

HELP !!!!!!

[Stephen L.]

Re: C2 throwout bearing/L79

I just looked at my L36 throwout bearing. It does not have a Cam looking appearance. I did take some photos that I will send to you of the bearing and the clutch arm. Does the clutch make noise with the transmission in gear and the clutch depressed? The reason I ask is this causes the input transmission shaft and clutch disc to stop while the flywheel/pressure plate continue to turn. If the noise continues then the throwout bearing or the pilot bushing in the crankshaft end may be the culprit. If the noise stops then you may have a problem with the input transmission bearing and associated stuff or possibly a gear in the transmission close to meshing (ala misadjusted linkage)

[John Thomas]

Re: C2 throwout bearing/L79

The noise happens when I push in the clutch pedal to shift gears or put the trans in gear. With the clutch out there is no noise. Coasting with the clutch in and in gear and I get the noise. New pilot bushing and fresh rebuild on tranny. Of course that should not be taken as not possibly being the problem. I am leaning tward the cam lobe in the throw out bearing.

[Joe L.]

Re: C2 throwout bearing/L79

John-----

If you are using a GM #15680264, Delco # CT24AG, or another brand bearing WHICH IS A DIRECT CROSS-REFERENCE to either of the foregoing numbers, then you have the correct replacement bearing. If so, then the problem lies elsewhere.

[John H.]

Re: C2 throwout bearing/L79

I doubt if the "cam lobe" formation has anything to do with the issue - I've used many T/O bearings with this feature with no problems. Make sure you have the curled ends of the fork and the tension spring ALL inside the circumferential groove in the bearing; the design makes it easy to install it wrong, with the curled fork ends capturing the flange at the back of the bearing, which causes all manner of problems. Also make sure you lube all three sides of the circumferential groove, the groove in the I.D. of the bearing, and the O.D. of the trans front bearing retainer with gray moly lube (very lightly on the bearing retainer), and lube the fork pivot ball. I'm assuming you have a bent-finger diaphragm clutch, with all the fingers at exactly the same height.

[Michael H.]

Re: C2 throwout bearing/L79

Hey John - I had the same "clicking" problem when depressing the clutch. I actually felt a "snap" in the pedal as the noise occurred. Check your clutch linkage, especially the cross bar where it attaches to the frame.

[John Thomas]

Re: C2 throwout bearing/L79-thanks

Thanks all for the information. I guess I'll pull the darn thing again. Hopefully this will be the last time. If not do you know anyone who wants a one owner with a noisy throw out bearing?