Clutch Problem

[Roland/Pittsburgh]

I just started my engine after a rebuild of engine, clutch and transmission. Everything is set up to specs. I can't shift into gear (grinding) with engine running with clutch disengaged. If I shift into gear with engine off, I can start the engine with clutch disengaged and all appears normal. Car doesen't move until clutch is engaged.

It appears the transmission shaft continues to spin with the clutch disengaged unless there is more drag than just the transmission input shaft and cluster gear.

Anybody out there experience this? I would sure hate to tear everything down to determine how to fix this problem.

[James Rogers]

What kind of grease does the tranny have in it?

[rotorwrench]

Another question, was the flywheel housing and flywheel alignment checked prior to installation of the engine? The reason I ask is that if it happened to be out of alignment a significant amount it may cause the clutch disc to rub with enough friction to turn the trans main input drive shaft. The clutch should feel a little grabby while released after starting with the clutch pedal depressed while the trans is in low gear.

James Rogers' question is valid too. If the trans lube is relatively low viscosity, the main drive shaft & counter shaft may take a while to slow down after you depress the clutch pedal.

Kerby

[Tom Endy]

My suggestion is to remove the inspection plate from the bell housing. Shine a light inside and with a mirror see if the yoke on the center of the clutch release shaft is actually in the bosses in the throw-out bearing housing. It is possible when putting things togeter that they were not and the adjustment made to the trunion nut assembly would have been false. happened to me one time.

Tom Endy

[Roland/Pittsburgh]

Thanks for your responses. The lube is 600w to the proper level. Maybe I should try 50% STP with the 600w. The flywheel and housing were checked with dial indicators for alignment. The flywheel was within .0005". The housing was within .005". The clutch action was very smooth with no roughness or chatter.

[Roland/Pittsburgh]

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Response to Tom Endy

The coverplate has been removed and a visual inspection made of all components that can be seen. All appear normal when the clutch is actuated. The yoke bears properly on the throw-out bearing housing.

[Mitch//pa]

could the input shaft nose be hanging up in the pilot bearing

[ken ct]

Originally Posted by Roland/Pittsburgh

Thanks for your responses. The lube is 600w to the proper level. Maybe I should try 50% STP with the 600w. The flywheel and housing were checked with dial indicators for alignment. The flywheel was within .0005". The housing was within .005". The clutch action was very smooth with no roughness or chatter.

Who the heck ever told you to use 600w grease. Use 90-120 gear oil in there. Depends also where you bought it the clutch assembly.? Lots are China made junk. Use Fort Wayne Clutch in Indiana. OMO ken ct.

[PC/SR]

Had the same problem. It sounds like the pressure plate fingers are not adjusted right and they do not completley release the clutch disc from the flywheel. First check the trunion adjustment to not more than one inch of free play. If that does not do it, measure the clearance between the throwout bearing and the fingers through the inspection plate opening. Should be about .100 with the throwout bearing all the way back. Use a piece of baling wire as a feeler gauge secured to a long string so you can retreive it when you drop it, and you will drop it. If there is too much clearance, the fingers are not going all the way forward and therfore not fully releasing the facing on the pressure plate. If this looks like the problem, let me know and I will send you directions for making the adjustments in the car.

[CWPASADENA]

Sometimes with a new clutch , it takes a little use to get the "Fuzz" worn off of the facings. I would try to adjust the clutch with very little free play (but just be sure you are not runnung on the throw out bearing with your foot off the pedal) and drive the car a few miles and then re-adjust the clutch. You may find everything will be OK.

I also recommend Ft Wayne Clutch. I have had excellent success with their clutches.

Chris

[MikeK]

Did you replace the pilot bearing? A stiff or dry one will spin the input shaft.

[bogdonj]

just put in a new engine this year and the same thing happened to me. Adjust the clutch 1 inch of free play. this fixed mine. As soon as I started the car up and got it running and got into gear it will grind and not allow me to do this. quick adjustment and I was good go.

[Tom Wesenberg]

600W is the correct gear lube for the tranny and rear end. No STP is needed.

Have you checked the clutch arms for cracks, to make sure the clutch fingers are travelling the full amount to release the clutch disc?

I installed a Model A clutch 2 days ago and had to readjust the rebuilt pressure plate fingers. When installed the fingers were about 1 1/4" down from the pressure plate opening. I set them to 5/8". 11/16" has also been mentioned as a setting for the 6 fingers.

As mentioned, make sure all 6 fingers are set evenly.

[Roland/Pittsburgh]

Thanks to all who have responded. More background: The pilot bearing and throwout bearings are new. The clutch plate and flywheel were remachined including the flywheel step to insure correct dimensions. The clutch pressure plate was rebuilt by a reputable local shop. The clutch disc was purchased from Mac's in Lockport NY. It is slightly thicker than the original Ford Spec. The clutch fingers were set at nominal 5/8" from the cover and then fine tuned using a dial indicator for identical location.

Since discovering the problem, I have adjusted the trunnion to give about 1/2" freeplay at the clutch pedal. I believe I have full travel of the throwout bearing but I will measure this and report. The clutch does engage at a high pedal. I have attempted to smooth the clutch disc by partially engaging the clutch in low gear with the brakes locked. And I have put a few drops of wd-40 on the input shaft spline in case the disc was hanging up on the spline. None of these actions have resulted in improved operation.

[ken ct]

Just about every thing Mac's sells comes from China. ken ct.

[PC/SR]

Roland: Really sound to me like you have to re-adjust the pressure plate fingers. Mine too was adjusted to the specified 5/8" but still ground when trying to put in gear. Other things get worn, changed, etc and teh 5/8 may not be the right measure anymore. Check the TO bearing/finger clearance. As mentioned above, a piece of bailing wire about .100 thick worked for me.

[Roland/Pittsburgh]

To Ken/Ct. Thanks for your input. I plan to question Mac's about the origin of the clutch disc.

PC/SR: Thanks for your responce. I will not be working on the car until Tuesday but I plan to further investigate conditions between the components. In the post above you suggested a method you had developed for adjusting the fingers. I would be grateful if you would send this to me via e-mail.

Roland

[700rpm]

Did you replace the hub, or are you certain you have a Model A hub? The V8 hub looks like the Model A, but it's actaully shorter, and if you put one of those in you'll never get that clutch adjusted.

I don't understand the comment against 600w. That's the right stuff, as Tom W. said; and don't put any STP in anything on your Model A. If everything is as it should be, 600w is all you need.

[Richard Lorenz]

Les Andrews said 5/8 for the fingers, but someone else cited a Ford publication that said 3/4 inches.

[Roland/Pittsburgh]

Clutch problem update: Tuesday and Wednesday I tried to resolve the problem. I adjusted the fingers as recommended by PC/SR. I was very careful to use a wire gage to insure that the throwout bearing contacted the fingers evenly. When operating the clutch the fingers move 1" as measured at the throwout bearing surface. This would seem to be sufficient.

The above resulted in no improvement as the gears still grind and won't engage unless the engine is started in gear as before. It looks like I have done all I can without dismantling the clutch. It may be the pilot bearing is too stiff or the clutch disc has a burr on the spline that keeps it tight against the flywheel. Even with the cluster gear half submerged in oil, a small amount of friction on the clutch disc would keep it spinning with the clutch disengaged.

Again I appreciate the help of all who responded.

[Tom Endy]

Roland:

Sometimes you just have to take everything apart and carefully inspect everything. I would inspect the clutch disk carefully. According to Les Andrews' book the thickness should be a nominal .340". Check the outside diameter and the diameter of the inner metal hub to make sure nothing is binding. You may have a disk that is not correct for a Model A. If you are using the original Henry clutch set-up check the dimension of the flywheel step the pressure plate sets in. The measurement should be 1.123". If the clutch surface has been machined a number of times the dimension may have been lost. Check that the springs in the clutch disk are not rubbing the heads of the flywheel mounting bolts. This is caused by a flywheel that has been resurfaced too many times. You can sometimes grind the heads of the bolts down somewhat to provide clearance. If you are running a V-8 clutch set-up there are other things to look for. See the article on V-8 clutches on the "tech Articles" page at www.ocmafc.org.

Hope you find the problem.
Tom Endy

[Roland/Pittsburgh]

Tom:

Thanks for your comments. I will check all items carefully when I get it apart and report back at that time as to findings. Hopefully I can help someone else avoid problems. As posted above, the clutch disc was purchased from Mac's in Lockport NY. It is a Model A setup, not V8. The flywheel clutch was machined and the dimension of the step was supposedly held at 1.123". At this point, however, nothing can be taken for granted.

[Karl]

Originally Posted by ken ct

Who the heck ever told you to use 600w grease. .

Wasn't it Henry Ford ?

[1931 flamingo]

I don't understand: "The flywheel clutch was machined and the dimension of the step was supposedly held at 1.123". ".....
Paul in CT Is disc installed correct way?

[Kurt in NJ]

When you have it apart put the disc on the trans, spin it and check how much the disc wobbles --runout, perhaps the disc is bent.

A bent disc hub can give you a dragging clutch and still have full engagement with the pedal quite high.

[Roland/Pittsburgh]

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To 1931 Flamingo: I'm pretty certain the disc was installed the right way. I recall checking this at the time of assembly to be sure it was on correctly but as I said, at this point I can't take anything for granted.

To Kurt in NJ: You made a good point about a bent disc or hub. It is something I hadn't thought of.

Thanks to all for your interest.

[randy randolph]

les andrews book is wrong i found out the hard way.a good shop that does model a will know the wright setting.

[Ron in Quincy]

Are you sure you installed the clutch disc properly and not reversed ? You should have 1" free play at top of pedal to be sure the throwout bearing is not running and should not engage until you come out about 1' off the bottom.

You probable have checked these things but don't hurt for me to mention them.

Ron

[Mike]

I had the same problem on a 28 fordor, i pulled it all apart and the clutch was installed backwards. I am still getting ribbed for that mistake 20 years ago.

Mike

[Roland/Pittsburgh]

Today I took the transmission and clutch apart. I did not find anything that would account for the problem. The clutch disc was installed correctly. It was stamped "flywheel side". It ran true when rotated on the spline without wobble. It did not contact the flywheel retaining bolts. It slid freely on the spline. The thickness of the disc is .400". I have purchased a Disc from Fort Wayne Clutch for backup. It appears identical to the one that was in the car except it is .385" thick. I have not yet checked the distance from the clutch mounting surface to the friction surface on the flywheel so I will do that when I am able to get back to the project.

The transmission shaft spins very freely with lube drained from the tranny. I was looking for more drag here but without lube, it"s hard to tell.

It is not clear to me what force causes the disc to back away from the flywheel when the clutch is released. Can anyone explain this to me?

Again, thanks for any help you may offer.

[Tom Wesenberg]

No special force moves the disc away from the flywheel, but when the pressure plate isn't clampping it tight, it should just float between the flywheel and pressure plate surfaces. The 600W oil should help stop the movment. After driving my A for a few miles and getting the tranny oil warmed up, when stopped, it takes about 10 seconds or so after the clutch pedal is pushed in before I can shift into first without grinding. I use Mobil 636 gear oil.

[jimvette59]

Hi, I have had some trouble grinding gears and was told to slow down the idle. It worked. The 600 W trans gear oil from MACS sold today is not the 600 of yesteryear, read the label. I hope this helps. JIM.T.

[Roland/Pittsburgh]

I last posted about this issue on 9/29 after I had dismantled the clutch and transmission. I was out of town for a while and got back to work on it 10/12. A close examination of the clutch disc splines revealed a residue on one spline surface that first looked like a bit of rust.

When I assembled the flywheel, clutch and transmission, I had the engine on the stand in a verticle position so I could use a hoist to lower the heavy parts onto the assembly. I put a drop or two of loctite on the part of the transmission shaft that inserts into the pilot bearing to insure that the shaft would not rotationally slip in the pilot bearing when the clutch was disengaged.

After assembly, I tilted the engine back to the horizontal position in preparation for assembly into the chassis. Evidently, the loctite had not set and a small amount ran down and back into the spline, locking it so the clutch disc was held against the flywheel and not able to float between the flywheel and pressure plate.

The splines were cleaned and the transmission was was reinstalled and now the clutch operates normally. Loctite was not used in the re-assembly.

Thanks to all for your interest and comments about this issue.

Roland

[Dennis Pereira]

Thanks for the update Roland. I'm glad you solved the problem.

[Mitch//pa]

i am not sure exactly what you mean about the use of the loctite to stop the input shaft from turning in the pilot. all i ever use is a little grease on the input nose at the pilot. anyway glad your up and going now

[Pa Joe]

Roland, I have been following you post about the clutch problem with great interest. Reason being I got my engine out getting rebuilt and when I get it back I don't want to have the same problem. Way to much double work involved to have to pull it all apart again. My question is WHY the lock tight? I never heard of that. Best of luck and glad the problem is fixed. Must say very interesting post.

[Roland/Pittsburgh]

Bearings mounted on rotating shafts are usually designed so that they are a shrink or press fit. This prevents rotational slippage between the shaft and bearing inner race. When there is clearence between the two, this slippage causes wear over time. This is considered acceptible in automotive design practice for the pilot bearing only since most cars are not expected to run as many miles as our model A,s. The more clearence, the faster the wear occurs. My input shaft was a few thousands undersize but not enough to consider a sleeve or welding up and remachining. I thought the loctite could help prevent the movement and reduce future wear.

As Mitch//PA points out, a lubricant on the nose of the shaft also can help prevent wear at this point even though the slippage continues to take place.

Roland

[Mitch//pa]

Originally Posted by Roland/Pittsburgh

Bearings mounted on rotating shafts are usually designed so that they are a shrink or press fit. This prevents rotational slippage between the shaft and bearing inner race. When there is clearence between the two, this slippage causes wear over time. This is considered acceptible in automotive design practice for the pilot bearing only since most cars are not expected to run as many miles as our model A,s. The more clearence, the faster the wear occurs. My input shaft was a few thousands undersize but not enough to consider a sleeve or welding up and remachining. I thought the loctite could help prevent the movement and reduce future wear.

As Mitch//PA points out, a lubricant on the nose of the shaft also can help prevent wear at this point even though the slippage continues to take place.

Roland

roland not trying to bust your stones but i think i understand better now that you were locktiting the nose of the input shaft to the inner roller bearing cage of the pilot. i never heard of doing that before to stop wear between the two. also what about crankshaft end play that would create in and out movement of the pilot on the input shaft. there is expansion and contraction from heat of the 2 components. i dont think you will have any kind of wear problem. am glad you got it going alot of extra work though just use grease next time. IMO..