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Discussion Starter #1
After my car has sat for 3 months, the throwout bearing 'growls' when I push the clutch in. Any thoughts on cause? It made no noise all last year.

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Rick Dorion
69 RS Conv,355,M20,4.10's and I don't worry about stone chips ( yet ).
 

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It might be the pilot bushing in the end of the crankshaft. These have a tendency to growl sometimes after a long period of storage.

They usually quiet down after a couple of laps around the block. If it's the throwout bearing, the noise will be there when you step on the clutch regardless of vehicle speed. If it's the pilot bushing, it probably will only growl when the car is stopped.
 

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Rick,

How far did you drive it once it started making the noise? Did the car get fully warmed up (15-20+ driving)? How old is the bearing?

Getting some heat into the bearing by driving may help as it will allow the grease, which channels to the outside of the bearing raceway, to release some oil. This may reduce some of the noise but may not cure it. If it keeps on growling then the bearing is likely shot.

After sitting the bearing raceways are not well lubricated since most of the oils are gone and the old grease, which is channeled away from the raceway, has not yet released any oils to form a lubrication barrier. It takes a while for the clutch bearing to heat up. Grease condition is the key but not something that we as car owners can control.

One possible reason that this happend is that the bearing may have a small amount of corrosion on the raceways. This happens when sealed-type greased bearings (such a s T/O bearings) are hot and then allowed to cool and sit for an extened period of time. This heat-cooling cycle causes condensation to build in the air space within the bearing. Combine this condensation with grease and you get an acid formation at the juncture of the two, which can cause corrosion. This condition can also happen with oil-lubricated bearings as well.

The best way to avoid this from happening is to periodically rotate the bearing.

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The Red Beast http://www.geocities.com/casanoc
 

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Discussion Starter #4
Hmmm. I drove it home from the place it was at for new floors. About 15 miles. It is a LITTLE more intermittent. I'll see if it goes away. I guess with the tranny out, if it comes to that, it will be a good time to paint the undercarriage. I don't know how old it is other than less than 5 years. The previous owner had a new clutch installed.

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Rick Dorion
69 RS Conv,355,M20,4.10's and I don't worry about stone chips ( yet ).
 
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