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Steve_O

C-161 motion control cam pivot rod assembly

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I bought a 1979 C-161 auto.   The plastic cam follower (P/n 5996) was broken.  

I ordered a replacement and went to install it tonight.  The pin was offset from the cam hole by ~1/8 inch.

 

As I dug deeper, it looks like the tang on the pivot rod (p/n 106316,  #13 on the parts diagram) had fractured and allowed the assembly to shift outboard.   

This is what broke the plastic cam.   It's been this way for a while, as someone has shimmed motion control lever detent outward to account for the shift.

 

Now, my problem is I can't get the cam pivot rod out from the assembly to replace the tang.  

I'm assuming the frictions collars (#6 and #12) are supposed to rotate on the shaft, and the friction cone is keyed to the shaft.

The collars must have rusted to the shaft, and that is what broke the tang off the rod.

 

Should I be able to drive the rod out toward the tanged side?  Heat, penetrating oil and persuasion?   Or cut it out and find or make a replacement?

 

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Edited by Steve_O

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I would say you may be hanging up on woodruff key #15, as i had the same problem with one of my C141's.

 

After rereading your post, and looking at your picture it looks to me like your carrier #1, (for the engaging ball) could also be bent possibly. (Optical illusion?)

 

I think I would cut the shaft (#13) out any i could, and replace it, as the way I understand it the shaft is broke as is. I would think there are enough parts tractors that you could get one from someone.

 

 Maybe someone has a better idea.

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Here is a pic or 3 of the mechanism.  The CONE does not turn, due to the WOODRUFF key holding it.   You need to release and remove the spring and center parts to get at the TINY WOODRUFF key.  The WOODRUFF key also stops you from driving out the center shaft.   DO NOT CUT THE SHAFT.  

I can provide replacement parts...and the 5996 nylon cam too. 

 

 

MOTION 001A.jpg

MOTION 003.jpg

MOTION 006.jpg

MOTION 007A.jpg

Edited by daveoman1966
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R.L.,  The bracket in  #1 has seen some abuse, but the real problem is that the broken tab on #13 lets the whole assembly shift left.  Somebody stacked washers behind #3 to compensate for she shift. 
 

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DaveO, 

I'm assuming the tab is supposed to be welded to the shaft. 

The tab is supposed to retain the shaft within the frame and prevent rotation of the shaft.

The motion control assembly is supposed to rotate about the fixed shaft.

The collars #8 and #12 are keyed to the bracket by the flat in the bracket (they rotate with bracket).

The cone is keyed to the shaft by the woodruff key.

Does this sound right?  (if it is correct, I don't really understand the purpose of the brass bushing shown in your photo)

 

Right now, my shaft rotates within the frame.   The assembly is located by #16 cam return bearing scrubbing against the frame.

#6 friction collar is seized to shaft.  Coned #11 is also seized to cup #12 friction collar.

The only way to disassemble these parts is to drive the shaft #13 out through the motion control lever bracket (toward the tab).

 

I've loosened the lock nut #7 and threaded the #6 collar out of the bracket, but this just drives the #1 assembly into the frame because the #6 collar is seized to shaft.

I'm thinking channel locks to free cup from cone, and then 5/8 box wrench on #6 + channel locks on cone to to free #6 collar from shaft.

Trying to drive shaft out through frame is likely to just cause frustration as the #1 assembly is one big springy mess.  There is nothing to react the impact.

 

There is no plastic in there, so heat is OK. 

Last resort would be to cut shaft to remove.  I'll likely need replacement parts.

 

Edited by Steve_O
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I would try making a puller (actually a pusher) using two pieces of heavy angle iron and two threaded rods, one above and one below the console to press the shaft thru a clearance hole in the left angle iron.   

Old tractor frames make good pullers and sockets make good press spacers.    With a lot of pressure on the shaft   and a shock with a BFH, you may get lucky and pop it loose.

 

Oh, good luck Steve and :text-welcomeconfetti:to :rs:

Edited by Ed Kennell
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I stand corrected.... the SHAFT does NOT turn at all.  The entire apparatus, except the COLLAR turns ON the shaft. Take the big nut off, then unscrew the hollow pipe.  That will release spring tension .  Now, tap the shaft just a bit 1/2" or so to expose the woodruff key.  Take that key out and it all comes apart.     

The BRASS collar... I can see it in your last pic...don't loose or damage it.   

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DaveO, nut is loose, but the hollow pipe is frozen to rod.  

 

Ed K.  Good thinking.  I've done this to  press/bang pins out of a trailer brake actuator where the trailer hitch assy was too wobbly to drive it out with impact alone.

 

Once I get it out, I'm going to need to weld on a new tab and clean up the rod.  At that point am I better off just cutting the rod out, pressing off the hardware and starting with a fresh rod?

 

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If you have a new rod or the means to make a new one, yes, cut it out.

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With the big nut off, unscrew the hollow tube with an open-end wrench as in my pic.  You MAY need to use some penetrating oil as the hollow tube could be stuck on the shaft, as well as in the threads of the collar # 8.  That collar has one FLAT side to fit the 'square' frame of the motion control assy lever.    QUESTION... how long is the center shaft????   

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DaveO, I backed the nut off, put 5/8 box wrench on the flats of the hollow tube.  Tried a 2 foot cheater bar, penetrating oil, and some heat from an oxy-acetylene torch.  No luck.

 

I'll have to get a measurement on the rod length.

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The central rod I have is from an earlier model C-160 and it is a bit shorter at 6 3/4" .  (That is part # 7604 and can buy new for ONLY $95.22).

Your rod s/b # 106316 (for a C-161) and is NLA.  However, I may have a parts tractor with that rod...will be back later.  Do ytou want just the 1/2" shaft, or all the stuff that goes on it?????

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Thanks DaveO.   Hold for now, I think I've got a replacement.   I'll let you know if I get stuck.  Thanks again for your help.

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I cut out the old rod.  Now have it working with replacement hdw from a C-165.

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