Clutch "clunk clunk clunk"

[Willynch]

Clunking noise when I depress the clutch. Just started. Louder the more the clutch pedal is depressed. Will start softly when the clutch pedal is barely pressed, getting louder the deeper it goes. No transmitted "clunk" into gear shift knob.

Can feel it on transmission housing.

Can drive, shift but. Sounds fine in neutral, when in gear and driving.

Don't plan to drive much until I make sense of this

Thanks

[Keith True]

Watch the front pulley while somebody steps on the clutch.See if it goes forward and backwards as they step on the pedal and let off.If the thrust surfaces on the babbit are getting worn it will let the flywheel go further ahead than it should.It can actually slide ahead enough to hit the bosses on the flywheel housing.It can also hit the starter bolts if they are too long.Then again,you may just have a throwout bearing going south,but I've found the deep noise is the flywheel hitting something it shouldn't.

[Mitch//pa]

What Keith said....I would also remove the inspection cover and take a gander

[Synchro909]

A couple of years ago, I had this problem and it turned out to be the ring gear had moved on the flywheel. It touched something when the crank shaft moved its few thou forward when the clutch was pressed. I never bothered to find out what it touched - I just fixed the problem by tapping the ring gear back into place through the starter motor opening and adding a few drops of Loctite # 290. Like i said, that was a couple of years ago and there has been no problem since.
Maybe you should check the ring gear for run out either through the started motor hole or through the inspection cover as Mitch said.

[ian Simpson]

I had the same problem. My crankshaft moves when I depress the clutch pedal and my ring gear moves forward periodically, also, I had an overlong bolt securing the starter which would strike the ring gear when it moved.

Solution:

1: remove the starter and make sure the ring gear is not moved forward. It can be tapped back and keyed as necessary through the starter motor hole.

2: Check that you have the correct length starter bolts.

3: rebuild your motor and including new crankshaft thrust washers.


Guess what I did???

[jw hash]

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sound like the ring gear is coming off the flywheel and hitting on the starter bolts.

[James Rogers]

Sounds like a bad throw out bearing. When you just lightly press the pedal, do you feel the clunking in it?

[Willynch]

Yes. Just barely depressing the clutch pedal will result in very soft rhythmic "clunk" I can sort of hear it. I can feel it with my let foot. The deeper the clutch pedal is dressed, the louder the clinic.

Watching the engine when the clutch is depressed; I do not see anything move (like the front pulley as suggested I look for By Keith True).

Im a novice mechanic. Can I find directions/instructions on access to the inspection plate in one of the manuals?

Thanks for all the insight

[Dollar Bill]

Just pull the floorboards and you will see the inspection cover.

[Patrick L.]

My first thought also was of the release/throwout bearing.
As said, just remove the floorboards and you'll see the inspection on the bell housing, its held with 2 screws. Remove it. With engine running watch the bearing contact the pressure plate very lightly while depressing the pedal with your hand. If the noise can be heard or felt with the bearing just barely contacting the fingers enough to just make it start to spin, I think you found your problem.
If it takes more than light pressure for the problem to rear its head, then the problem is deeper into bell housing as mentioned.

[Cool Hand Lurker]

Originally Posted by James Rogers

Sounds like a bad throw out bearing. When you just lightly press the pedal, do you feel the clunking in it?

I agree with James, bad throw out bearing. Willynch, you mentioned that you are a "novice mechanic". If you have never replaced a throw out bearing or removed a Model A transmission you should get some help. Preferably from someone who knows the Model A. See if there is a local club nearby that can help out.

[Marshall V. Daut]

Read all the comments in the following link, especially comments #10, #19 and #22:
https://www.fordbarn.com/forum/showthread.php?t=174695
I think this will solve your problem.
A bad throwout bearing usually causes a scraping noise, not a knock. If the ring gear is tilting forward in one spot (very common!), even a 0.010" thrust slop will allow it to hit the reinforcing ribs on the inside of the flywheel housing. You probably won't be able to see that small of a movement at the crankshaft pulley, so don't rely upon a visual inspection alone for crankshaft movement. Take five minutes and remove the starter so that you can check the ring gear during all 360 degrees of its travel. That would be a MUCH easier fix than IF the throwout bearing is bad. Pray for a "walking" ring gear to be the problem = a five minute repair with a hammer and punch.
Marshall

[Synchro909]

Originally Posted by Marshall V. Daut

Read all the comments in the following link, especially comments #10, #19 and #22:
https://www.fordbarn.com/forum/showthread.php?t=174695
I think this will solve your problem.
A bad throwout bearing usually causes a scraping noise, not a knock. If the ring gear is tilting forward in one spot (very common!), even a 0.010" thrust slop will allow it to hit the reinforcing ribs on the inside of the flywheel housing. You probably won't be able to see that small of a movement at the crankshaft pulley, so don't rely upon a visual inspection alone for crankshaft movement. Take five minutes and remove the starter so that you can check the ring gear during all 360 degrees of its travel. That would be a MUCH easier fix than IF the throwout bearing is bad. Pray for a "walking" ring gear to be the problem = a five minute repair with a hammer and punch.
Marshall

And don't forget a couple of drops of Loctite 290 to prevent it happening again. 290 is a wick in grade that finds its way into the microscopic space between components (ring gear and flywheel in this case) before it sets. Removal in the normal way is possible but a little heat makes it even easier. Once the ring gear has moved once, it is more likely than before to happen again. Like Marshal said, pray it is the ring gear as the fix is sooo easy.

[jw hash]

my bet is the ring gear is hitting one of the starter bolts. it is more common then one would think. a friend had his trans out two times. then he put the car on a trailer and brought over here and in ten minutes we pin pointed the problem. the ring gear had moved. and was hitting the lower starter bolts.

[Synchro909]

Seems the consensus is coming around to "The ring gear has moved" Willy, Please let us know what you eventually find as the problem. I'm sure many will be interested.

[Franchise_24]

Originally Posted by James Rogers

Sounds like a bad throw out bearing. When you just lightly press the pedal, do you feel the clunking in it?

I had about the same issues and sound and it was a bad throw out bearing as you said. Replaced that and the noise was gone.

[ian Simpson]

I gave the short version of my problem in post #5 above. What I did not say was that as a Model A novice I based my initial analysis on my experience with other classic cars and assumed a bad throw-out bearing. I, with the help of my son, pulled the rear axle, transmission, et al and replaced the throw-out bearing. Did not fix the problem!

The next week end, with the help of my mechanic brother-in-law, we repeated the process with no improvement. Again no improvement. We then suspected a damaged starter and Bendix and replaced both. The problem went away. Further analysis showed that one starter bolt was over length and in replacing the starter the offending bolt was moved to a position where it did not strike the ring gear. Looking through the starter hole at the ring gear, it was obvious what the problem was. A few taps with a hammer and punch put the ring gear back in place and the problem went away.

Moral of the story? Fix the easiest thing first. Check the ring gear and starter bolts when you get the dreaded clunk-clunk-clunk.

[Willynch]

Ian,

Thanks! Im a surgeon (not smart enough to be a good mechanic) and have a similar philosophy at the office.

Taking out one organ, than another, than another until you eventually find the problem makes patients grumpy but lawyers excited!

Will work from simplest to most complicated, limited by my skills and resources (i.e.- my brother in-law is an administrator, not a mechanic!)

Will follow up as I make progress or destroy my car.

[Mitch//pa]

Is there any Model A people around you that can help with exploratory surgery and diagnosis

[Cool Hand Lurker]

Originally Posted by Willynch

Ian,

Thanks! Im a surgeon (not smart enough to be a good mechanic) and have a similar philosophy at the office.

Taking out one organ, than another, than another until you eventually find the problem makes patients grumpy but lawyers excited!

Will work from simplest to most complicated, limited by my skills and resources (i.e.- my brother in-law is an administrator, not a mechanic!)

Will follow up as I make progress or destroy my car.

Oh Lordy, Lordy, be careful of those fingers! I can't tell you how many time my fingers have been smashed working on cars. They heal, but lack of sensitivity and arthritis effects don't go away. You can be careful but you never know when something inanimate suddenly decides to move.
And you can never get the grease out of the friction ridges.