Re: clutch replacement project, etc.

Tue Feb 18, 2014 11:44 pm

Fireman Bob wrote:.............I am not disparaging the graphite system but almost every clutch throwout system in the last 50 years has used a roller bearing with great success.
I am by no means disparaging using a roller bearing. I just want the potential issue with using a roller bearing to be clear to anyone reading this now or down the road. The difference is that all those systems you mention were DESIGNED to use a roller bearing. The Cub mechanism was DESIGNED for the graphite. Keep in mind a Cub was originally designed to be inexpensive and last seven (not seventy!) years. There are several "corners cut" that could have been engineered differently. One being the TOB mechanism, no use spending the time, money, and engineering to make it always perfectly centered with a more complicated mechanism when IH could use a graphite block and some flat strap metal bolted together and aligment of the TOB to clutch fingers can have a little offset and fully function without harm.

Fireman Bob wrote:........
While there will be some lateral/radial movement between the clutch fingers and the bearing if everything is not centered both of these surfaces are hardened to over Rockwell 55 and should easily tolerate this.........
I hope they do tolerate it but put two pieces of metal together with no lubrication and move them back and forth at a rate of 1800 times a minute. If the TOB is not centered every time the engine makes one revolution the clutch fingers have slid out and then back on the face of the roller bearing. Longevity of the roller bearing really depends on how often you use the clutch, how far the fingers slide, and how fast the engine is turning. If clutching infrequently the fingers and TOB could cool off between clutching. If clutching more frequently, the fingers and TOB may heat up and be able to tolerate it, but it can't be doing the grease and seals in the roller TOB any good.

Re: clutch replacement project, etc.

Sat Feb 22, 2014 9:33 pm

Well, I was back at it today having been away during the week on work. I got the flywheel off OK and removed the rear engine seal retainer to have a look. That whole surface was oily, and I know that the tractor would moderately drip oil, but I also know that some one or more of the gaskets leak - oil pan and/or push rod cover. There was oil on the face of the rear seal retainer and where the rubber of the seal meets the aluminum of the retainer plate. So it seems it does leak a little bit at the seal in addition to those gasket leaks. The seal will not push out by hand. I wonder how I would force it out (if I should do that) without damaging the retainer plate. The seal does not appear to have rotated/slipped in the retainer plate given how tight is seems. And best I can tell the retainer plate does not appear to be warped. Also, the spring around the circumference of the seal had slipped out (years ago I guess) where you see the dents in the rubber looking at the 12 and 2:30 o'clock positions in the image below looking at the back side of the retainer plate. I pushed the spring back in. There is also a small chip in the rubber at about the 4:30 position in that same image. Otherwise the rubber is still flexible and crack-free after 65 years. So I'm wondering what to do. I'm weighing the certainty of an apparently small leak against the uncertainty of the various methods I've read about (and not experienced myself) for replacement, fixing it, tolerance issues of new seals, damage to the retainer plate, potential for the fix to also leak, probability of existing seal to get worse, etc. I'm not even sure if new seals have the same rubber bonded to metal design that the original one seems to have. What do y'all think? I guess if I had more confidence and knowledge in the solution(s) I would go for it.

Lastly, what is that part bulging out just to the top left of the retainer plate? Is it possible/advisable to replace the gasket to that thing?

thanks alot guys
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Re: clutch replacement project, etc.

Sat Feb 22, 2014 10:01 pm

The part bulging out is your oil pump. If it's leaking there is a super thin gasket behind it.

Re: clutch replacement project, etc.

Sun Feb 23, 2014 1:15 pm

twotone wrote:... If it's leaking there is a super thin gasket behind it.


Get an OEM gasket. If you put in a gasket that is too thick -- no oil pressure and you will have to tear the Cub apart again to replace the gasket with the proper one.

Bill

Re: clutch replacement project, etc.

Sun Feb 23, 2014 2:22 pm

Bill Hudson wrote:
twotone wrote:... If it's leaking there is a super thin gasket behind it.


Get an OEM gasket. If you put in a gasket that is too thick -- no oil pressure and you will have to tear the Cub apart again to replace the gasket with the proper one.

Bill
:Dito: That gasket thickness is CRITICAL.