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1930 Model 745 clutch and pressure plate


Guest Len Sholes

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Guest Len Sholes

I am wondering if anyone can help me with a problem that I have with the clutch not releasing correctly. To give you the history of what has taken place is as follows. The car has been sitting for approximately 19 years, I rebuilt the engine doing an in frame. Started up engine and went to put in gear and found that the clutch was not releasing. Removed the transmission and clutch and found that the friction plates were frozen or rusted to the center plate. I cleaned up all the pieces and had the plates relined with new cintered bronze material like there was on the plates that were in the clutch assembly. I reassembled everything and started up unit and still had the same problem. Removed the clutch assembly again and double checked everything and at this time talked to a fellow who does a lot of work on Packards and he told me to check the center plate for been warped, told me that I needed to have .040 inch clearance between the center plate and the friction disc and also advised me the procedure for adjusting the three screws on the pressure plate. I did all of this and reassembled the unit. I must mention that when I reassembled everything back onto the engine the first time I found that I had to have the clutch linkage adjusted to almost it full length in order to get the feel that I was compressing the fingers on the pressure plate. This was also the same way when I installed things the second time. At this time when I started up the engine I could get it into gear with out any grinding takeing place. However after I took the car for a short drive I was back to the same problem that I could not get it into gear with out having to grind the gears. Not been happy with this I removed the clutch assembly again to double check everything. I measured the thickness of the new lining and found it is .130 inches and according to what I have been told this is the correct thickness. I then had the two friction discs and center plate chucked in a lathe to check to see if they were warped and found that there is nothing wrong with them as they are running true with less that .002 difference on the center plate. After this check I have to think that the two discs and center plate are not my problem. The only thing that is left is the pressure plate and that is where I am looking for some help. Does anyone have information on what the height of the release fingers should be when you have the unit all assembled and bolted up to the flywheel. I have to think that this is where my problem is as I think the fingers are to low and this is why I have had to adjust the linkage so much in order for me to get the clutch to release. My thoughts are if I had them adjusted higher then I could shorten the linkage and this would give me more travel on them which should bring the pressue plate back further thereby taking the pressure off the clutch plates when I depress the clutch pedal. There has to be specifications on the pressure plate some where as years ago mechanics rebuilt them as we didn't live in a world where you used rebuilt components. Thanks for any information that you can share with me as I am at a stand still as what to do next.

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What weight fluid do you have in the trans? Should be 600 weight, commonly known these days as "steam cylinder oil". We had a similar problem with a '31. Heavier trans lubricant made all the difference in the world. Also check to be sure the clutch disc is not installed backwards. Very easy mistake to make.

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Guest Len Sholes

Thanks Restorer 32 for your response. Yes I have 600W oil in the transmission. You mention about making sure I have the clutch plates installed correctly. I have put them back in the same order that they were when I first took it apart. Now that is not to say they were in there in the correct order. The way that I have them is that the plate that is attached to the spline hub is against the flywheel and then there is the separator plate with the second disc been between it and the pressure plate. This is the disc that has the square openings in it that mesh with the lugs on the other plate. I have the heads of the three 1/4 inch bolts and the springs on the pressure plate side with the nuts and cotterpins on the flywheel side. Is it possible that you can advise me if this is the correct order? Unfortunately this kind of information is not in the service manual that I purchased before I started working on the car.

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Guest Len Sholes

I purchase it from a local business that sells Model T and Model A parts. I have been getting it from this place for the last 20 years.

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My information is specific to a '29. We hassled with the same problem. On the '29 the castellated nuts and spring tabs should be toward the pressure plate side. We did a '29 and a '31, the '30 could be different I suppose. To quote from the service manual..."There are three adjusting screws on the spring and cover assembly which should be adjusted to 1/32" after the cover and spring assembly have been replaced and tightened to the flywheel or screw down until point seats on driving plate, then back out three notches". Good luck!

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Another thought. Make sure your pilot bearing is allowing the trans main shaft to come to a full stop when necessary. I would suggest putting the trans in neutral, taking the top off the trans, starting the engine, depressing the clutch and checking whether the shaft is indeed coming to a stop or is being dragged along by the clutch or pilot bearing. Watch for splashing oil unless you are particularly fond of the odor of 600w. A badly worn front transmission case bearing could also allow the shaft to turn easier than it should I suppose?

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Guest imported_Speedster

I just bought a 700 series 'Factory Instruction Manual' on eBay. So when I get it in a few days, I'll check if there is anything in it that might help. It's supposed to have info on clutch assembly. I figured it would help with my 600 series cars also, if I run into any simular problems.

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Guest Len Sholes

Thanks Speedster for your replies. Well I finally got the clutch to release. Last week after having installed the clutch and transmission again and still having the same problem I removed the clutch for the third time and talked to a local clutch and pressue plate rebuild shop. I sent them the clutch and pressure plate to check it all out and to see if they could determine what the problem was. They advised me all they could really come up with was that the fingers on the pressure plate were to low and they adjusted them. This morning I reinstalled the clutch and transmission again started up the engine and found that it was still not releasing correctly. I called the repair shop and they advised me that I should take them the clutch and pressure plate as well as the flywheel so they could try and determine what the problem was as they needed to make sure on the flywheel demensions. Once again I removed the trans and clutch assembly and also the flywheel and took them to their shop. They assembled all the pieces on their work jig and they found that when the pressure plate was activiated to the release position the clutch plate nearest the flywheel was not releasing fully ( had a drag on it) but the other plate nearest the pressure plate had released correctly. Not having any specs on the pressure plate he adjusted the release fingers so they were higher and would have more travel and he checked the plates in the release mode again. It was better but still not the way it should be so he adjusted the fingers some more rechecked and now when the fingers were depressed you could rotate the discs. He then set the clutch discs, center plate and pressure plate on his jig using spacers that were the same dimension as the flywheel and rechecked it to verify that it was still releasing correctly. This way you can see the two clutch discs and you can insert a feller guage to make sure you have clearanc. It all checked out that it was releasing correctly. I returned to the vehicle and reinstalled everything and now I had lots of clutch pedal in fact I had to shorten the linkage back to where I thought it should be for a new clutch. I started up the engine depressed the clutch and now the output shaft on the transmission stopped rotating and you could put it in any gear with out any grinding. Finally I had it working the way it is suppose to work. For your information the measurement that I got from the tip of the release finger to the top of the pressure plate cover (used a straight edge across the cover) was .750 inches. The first time I took this measurement this morning it was 1.00 inches. So as you can see it took another 1/4 inch of adjustment to get things to operate correctly. If you are having this problem I would almost bet that this could be your problem. For your information I have approximatley .040 inch clearance between the center disc and the clutch plate and the three screws on the pressure plate cover where tighten up until they touched the plate and then were backed out 3 clicks. Good luck with yours.

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Guest imported_Speedster

I did the 'finger-tips to straight-edge across cover' measurement on the '29 clutch and found that it is Much different. There is also a large variation in that measurement, which I'm sure is not correct? Of the 6 fingers the closest was .16", 2 others were about .23" and the other 3 were about .50". So looks like I need to do some adjusting also. (The close 3 were all on one side of clutch, not everother one.) I may adjust them all to .5" and give it a try, unless someone knows what that should be on the '29. I'm not sure if the '29s clutch is different design than the '30s or not, but I would think they would be similar? It was in very good condition for the mileage on the car (must have already been replaced) and I don't think linings will need to be replaced. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" />

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Guest imported_Speedster

There should be an adjustment Spec on that somewhere in the manuals? I'll try to find it.

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Guest imported_Speedster

The '29 Service Manual shows a 'special gauge tool' for doing that adjustment, but I can't find a measurement spec anywhere. In the pictures, in manual, the fingers appear to be very far out, so the .2" may be more correct for New clutch linings.

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Guest imported_Speedster

Here's a picture. The fingers at bottom and on right side are the ones at .5" and the ones at top and left are about .2". The ones on top and left appear to be the same as the assembly pictured in parts manual.

See Attachment:

post-33516-143137887473_thumb.jpg

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Guest imported_Speedster

I also noticed that there is no way to lock those finger adjusting screws. It seems to me that there should be lock nuts on them but there isn't enough threads above the single nut to do that? No wonder they get out of adjustment. <img src="http://forums.aaca.org/images/graemlins/frown.gif" alt="" /> I'll put some thread-locker on them, which should help some.

I desided to adjust them all to .25" in front of backplate, and try it.

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Guest imported_Speedster

Has anyone else had experience adjusting clutch fingers on late '20s or early '30s Packards ? If so, are there adjustment specs anywhere?

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Guest Len Sholes

Rick, the photo of your pressure plate looks just like the 1930 one. Are you measuring the height of the fingers with the pressure plate on the bench or on the engine. The measurement that I took was with everything all bolted up to the flywheel. The way to adjust the fingers is thst you first have to knock the tab of the nut back out of the slot in order that the nut will turn on the bolt. I have a small thin chiesel that fits in the slot and I just tap it a few times on both sides to bend the metal out of the way. Be careful or you will split the bolt. Next you use a screwdriver to hold the bolt and use a wrench on the nut. Once you have it adjusted you need to lock the nuts again. Lock tite will work but I think in order for this to happen you need to have the threads on the bolts and nuts really clean. Just a word of caution I have not been able to find a supplier for this type of nut or bolt if you ruin one. As for the thickness of the clutch material I was told it should be .130 inches thick and this is what is on my clutch and it appears to work ok. If you live in a location that has a clutch and pressure plate rebuild shop I would suggest that you take them the clutch discs, center plate and pressure plate. You will also need to measure the length of the 6 mounting lugs in the flywheel or take them the flywheel. What they can do is assemble the pieces on their bench using spacers that equal the length of the lugs on the flywheel and then clamp it down. They now will be able to simulate a depressed clutch pedal and be able to check to see if the clutch plates will rotate, if they do not then they can adjust the fingers and check it again. It would be nice if some one out there has the Packard tool mentioned in the service manual who could tell us what its dimension is. If a person knew what it was you could do the adjustment on the engine with confidence knowing that it was correct.Good luck on your project.

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Guest imported_Speedster

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> The way to adjust the fingers is thst you first have to knock the tab of the nut back out of the slot in order that the nut will turn on the bolt. I have a small thin chiesel that fits in the slot and I just tap it a few times on both sides to bend the metal out of the way. </div></div>

I did my measurement with it on the bench, which would account for the difference. <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" />

I checked again, and don't see any locking tabs anywhere or where there were any. No slots or groves in nuts. The bottom side of nut/washer rides on two raised bumps on both sides of holes. Maybe the '29s were made different in that area, they saw the problem, and added locks in '30. Unless it originally had tab locks and they were left off when the clutch linings were replaced, but I don't see how a tab would lock in place unless it just rode between the two bumps or do they ride in the nuts only? If inside the nuts only, what keeps them from falling out? In the above picture you can see one of the bumps below the adjusting screw on bottom right side of pic, but No Tabs on or in nuts ?

Sorry, but I'm having difficulty visualizing what these tabs look like?

My linings are almost like new, so won't need replacing. <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> The pilot and throwout bearings appear to be new also.

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Guest Len Sholes

Rick I think I have confused you re the locks on the clutch fingers. Like I said early your pressure plate looks identical to mine. The locks I am referring to are the 3/8 inch bolts and nuts that go through the pressure plate and through the outer end of the fingers. The lock I am referring to is in order to prevent the nuts from turning you need to bend the edge of the nut into the screw driver slot and I do this with a small chiesel, however before you can hold the bolt with a screwdriver and turn the nut you need to make sure that the two areas on the nut that have been forced into the slot is driven out wards so you can turn the nut. If you try and hold the bolt and turn the nut with out doing this you can damage the threads.

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Guest imported_Speedster

Thanks, Len

Now I understand !!! <img src="http://forums.aaca.org/images/graemlins/smile.gif" alt="" /> The nuts are supposed to be deformed (staked). Got it ! <img src="http://forums.aaca.org/images/graemlins/wink.gif" alt="" />

I guess when the clutch was overhauled they forgot to do that on mine, cause they all turn freely. I'll try to crimp them a little before I reinstall.

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