Strange metallic sound on 1940 56S

[Daves1940Buick56S]

All:

At very low rpm (~400 or less) I hear a metal-on-metal sh-sh-sh-ing sound, like skiing on a metal surface. When the clutch is disengaged (pedal depressed) it ceases. My experience with throwout bearing noise is that you hear it with the pedal depressed and it ceases with the clutch engaged, the opposite of what I am hearing here. Any ideas on what this could be? Pilot bearing?

Cheers, Dave

[Mark Shaw]

How many years and how many miles does your clutch have on it?

[Daves1940Buick56S]

Dunno, figure infinity on both. I am going to have the clutch replaced and trans overhauled or replaced over the winter. I know the clutch has oil on it but this noise has been present ever since I have had the car, over a year.

Cheers, Dave

[Bleach]

Every manual transmission equipped car I've had, you could hear the throw out bearing with the pedal not pressed down when idling.

[trp3141592]

Hi,

Every manual transmission equipped car I've had, you could hear the throw out bearing with the pedal not pressed down when idling.

The throw-out bearing, although not under the pressure of the clutch pressure plate springs, is still in contact with the pressure plate fingers. So it is turning when the clutch is not depressed. I suspect you have a failing throw-out bearing.

The good news is that since you have already decided to replace the clutch this winter, and since a new throw-out bearing is always de rigeur anyway when doing a clutch, you're not out anything you would not have been replacing anyway.

Good timing--it's the END of the season, not the start!

--Tom

[FLYER15015]

Dave,

Just for now, check your linkage. Do you have about an inch of pedal play before it moves the throwout bearing lever ? It is adjustable down at the clutch equalizer. I did a whole thread on the equalizer, in that they are NOT available for the big series cars, and the holes, particularly the one that the pedal rod goes thru, tend to "waller out". Mine was paper thin at the front edge of the arm boss. Fortunately they are cast in steel rather than iron, so we tig welded mine closed and redrilled the holes. Made the action much more solid. I posted pictures of the "equalizer" in my album.

I had my clutch relined at Denver Clutch and Brake. They relined my brake shoes also at the same time, and turn around time was about a week. Price was VERY reasonable too.

Mike in Colorado

Edited November 17, 2013 by FLYER15015 (see edit history)

[danhar1960]

If the noise ceases when you depress the clutch pedal, to me it would indicate the input shaft bearing or cluster bearings are the problem.

Clutch out in neutral and they all rotate, clutch in and they don't, hence the noise goes away.

I've always adjusted my clutch so that the throw-out bearing ceases to spin when the pedal is fully released.

I had it drilled into me when learning to drive, DON'T ride the clutch. It stuffs the clutch plate and unnecessarily wears out the throw-out bearing.

Given that you intend to do the clutch and the transmission, It seems that one way or another, the problem should be solved.

Danny

[Daves1940Buick56S]

All:

Thanks for the responses. The plan is to get a rebuilt trans from Doug Seybold and have a local mechanic here do the work, probably in January. The car came with a new clutch disc, pressure plate, and throwout bearing in the trunk. Have to get a pilot bearing. Hopefully that will fix all of the issues behind the flywheel! Just leaving all of the issues in front of the flywheel, of course!!