B Clutch problem

rnicholas · Oct 22, 2019

So I completely rebuilt a BN, a '47 I think, and while I was at it I replaced the throw-out bearing in the clutch. But, I had no clutch
pedal when we put it back together so I adjusted the clutch rod in the torque tube. It would not disengage the clutch and I couldn't put it
into gear. So, I adjusted the clutch some more and forced it into gear with some loud hammering noise coming from the clutch. Those were
the fingers on the clutch breaking off when hitting the bottom of the collar behind the throw-out bearing. So, I broke it apart and replaced
the clutch with one from an old A and I still have the same problem. Either the clutch plate is not dis-engaging and I can't get into gear
or the bottom of the yoke behind the throw-out bearing is hitting the bolts that adjust the fingers on the clutch. And guys, if I have to
break this thing apart much more I'm going to lose my help (my brother).

Janicholson · Oct 22, 2019

If the friction disk is put in so the central torsion coil springs are toward the engine, the springs and plates that hold the springs hit the flywheel bolts and when the pressure plate is installed, the apparent thickness of the friction disk is much greater (than it actually is) this causes the fingers to move way away from the throwout bearing, and also prevents the clutch from ever releasing. The flywheel side of the friction disk is almost flat. The pressure plate side is where the center springs go. Jim

rnicholas · Oct 22, 2019

So, then, I've got the clutch plate (the thin disc) or pressure plate--whichever it's called--in backward? Is that what you're saying? I know that when I bolt the clutch to the flywheel the fingers really get depressed into the clutch toward the engine and it seems like the throw-out bearing would really have to travel pretty far to depress the fingers enough to release the clutch plate.

Curt Cooke · Oct 23, 2019

Sounds as if you may have installed the friction disk backwards. I strongly suggest you either obtain or borrow an IT manual or perhaps someone can get you a copy of the page that gives you and shows you the measurements required on the clutch fingers, etc. The book will tell you exactly which way to install that disk and what dimensions you should have when you have the pressure plate bolted up. Doesn't have to be perfect but get it close.

Janicholson · Oct 23, 2019

Exactly. The friction disk, also called Driven Disk, fits on the splines and is pinched between the flywheel and the pressure plate. Usually the fingers on a new disk and plate are near flat to each other, not dished in. They might be a bit dished outward if looked at from the point of view of the adjustment screws. (leave those alone, as 99 of 100 they are set from the factory and need no messing with them. Jim

Ken Hansen · Oct 23, 2019

(quoted from post at 12:04:51 10/23/19) Exactly. The friction disk, also called Driven Disk, fits on the splines and is pinched between the flywheel and the pressure plate. Usually the fingers on a new disk and plate are near flat to each other, not dished in. They might be a bit dished outward if looked at from the point of view of the adjustment screws. (leave those alone, as 99 of 100 they are set from the factory and need no messing with them. Jim

Good points here and also other above.

Just to keep terminology straight the pressure plate is the thing that is bolted to the flywheel and the clutch disk/friction disk/Driven disk terms all refer to the part with the splined hole in the center that the shaft coming out of the transmission slides over.

Often wish I had taken a picture of the way I made a support to make splitting my BN an easy one man operation.

It is basically a couple legs that bolt to the large holes on the side of the clutch housing with the 5/8 bolts for plow or other implements. They also have a couple wheels on the bottom.

Just need a smooth concrete floor and a floor jack to support under engine. Bolt legs to the housing, place jack under engine. Then simply unbolt the housing bolts attaching it to rear of engine. Once all bolts are out put PTO in gear and turn the PTO shaft with transmission in gear and it walks right back.

I do have the advantage of the large pulley for Woods mower so it turns easy.

Just turn shaft the opposite direction and it walks right back in place. Worst case, say if you don't have a PTO, would be to have a second person and move the two halves apart and back together by pushing on the rear tires!

gab · Oct 23, 2019

So does completely rebuilt mean you installed a new disc and pressure plate or just a throw out bearing?? because I don't see how you could screw up a throw out brg. install. But a disc put in backwards could probably do it.

rnicholas · Oct 23, 2019

Jim, the friction disk cannot be put in backward. I broke the B apart (for the third time) this morning and the friction disk, when turned around, will not fit flush into the flywheel because the bolts that attach the flywheel to the crankshaft prevent the disk from setting completely against the flywheel. I absolutely cannot figure this out. All I did when I rebuilt the B (for the clutch) was to replace the throw-out bearing. The clutch and friction disk were put back in as they came out. This is why I was puzzled when, first I had no clutch--the pedal went all the way down without any resistance--and then when I adjusted the clutch rod underneath the torque tube I had the sound of the yoke that moves the throw out bearing forward hitting the bolts that adjust the fingers (eventually breaking off the fingers). So, back to the start of this problem. Why did replacing the throw-out bearing give me no clutch pedal? We drove this B before the rebuild so we know the clutch worked (I only rebuilt the thing so my son could experience it). This is a fairly simple clutch assembly and I've replaced them before (in a 100 and an A) without any trouble. There's got to be something obvious that I haven't figured out.

rnicholas · Oct 23, 2019

Thanks. I haven't had too much trouble taking it apart and putting it back together. I have the front of the tractor held up with chains to
the gas tank support and two cultivator bars attached to the side of the tractor by the front wheels. The chains go to an engine puller.
Not as good a set up as yours but it was all I could figure out.

rnicholas · Oct 23, 2019

The friction disk will not sit flush into the flywheel when turned around. The bolts from the flywheel to the crankshaft prevent it from doing that. I have a parts manual and I followed the picture in the manual.

Janicholson · Oct 23, 2019

If 12 14 and 15 are where they belong, and 12 is not bent, some do get bent, The clutch friction disk and pressure plate must be causing the fingers to be pushed in so far that the TO bearing can't reach them. I wish I was looking at it in person. Jim
IH parts diagram

rnicholas · Oct 23, 2019

And that's what I sit on my shop stool and stare at--that once I bolt down the clutch into the flywheel, the fingers depress a great deal. Of course, they should depress some as the clutch should be engaged at that point. But I wonder if the fingers are getting depressed so much that the TO bearing can't push the fingers in far enough to disengage the clutch without the yoke hitting outside the clutch. I'm going to try and post some pictures even though it all looks normal to me. I keep going back to why changing out the TO bearing during the rebuild would leave me with no clutch pedal once we put the two halves back together.

Ken Hansen · Oct 24, 2019

I keep going back to why changing out the TO bearing during the rebuild would leave me with no clutch pedal once we put the two halves back together.

If you can post some pictures can you take a picture of the two throw-out bearings next to each other?

I could try to see if it is possible to see anything on my BN through one of the holes in the clutch housing latter today.

Janicholson · Oct 24, 2019

These are taken from the Blue Ribbon IH manual ! They are real. The cutaway view should help Best of luck, Jim

Janicholson · Oct 24, 2019

Here is more info from blue ribbon. Jim The second pic is the same as the first on the original post, Sorry.

Janicholson · Oct 24, 2019

New entry above in this post. Jim

rnicholas · Oct 24, 2019

Thanks for the numbers Jim. I'm going to do some measuring on what I can measure.

rnicholas · Oct 24, 2019

Thanks again Jim. This is interesting. I didn't know there was a way to remove the clutch with the springs still compressed. I had been just backing out the 6 bolts a little at a time until the clutch was free. Here's what I've decided to do. I'm going to bolt together the tractor and adjust the pedal until the TO bearing is about an 8th of an inch from the fingers. Then I'm going to check the release of the clutch (or the hitting of the yoke against the clutch) by turning the hand crank instead of putting it all back together and firing it up. Less frustration that way. This has got to be a matter of pedal adjustment so the TO bearing is positioned properly. If it's not then I'm back to square one. When I rebuilt my 100 some years ago I replace the TO bearing without any problems after I put it back together.

rnicholas · Oct 24, 2019

Thanks Ken. I'll have to find the old one. Some old parts I threw away and some I kept. I should have kept this as there was nothing wrong
with it. I just replaced it because that's what I do on a rebuild while the tractor is split.

Janicholson · Oct 26, 2019

Looking at the image of the cutaway, the fingers are shown pretty much where they should be when a new disk is in place. If yours are way in (concave) i would say something is incorrect in the clutch, not the TO bearing/mechanism. Jim

B Clutch problem

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