Clutch failure (AGAIN!) Ford 1100 4WD

[tosii2]

Bernie,
Good to hear from another 1000 series owner and one very similar to mine in this area, I believe.

Your experience is fascinating relative to my experiences. Some clarification, please about some of what you found in your situation.
You said there was a total lack of lubrication in the PP (pilot bearing?) and TO bearing. Since these are sealed units (at least in my machine!), how did you determine that they were running with no lube?

My sliding hub has a large groove, which I think is a grease reservoir, just forward of the O-ring that seals the aft end of the hub to the aft end of the boss. Mine was well lubricated, although the 'working' grease on the hub-boss interface was pretty stiff; I cleaned that up and put in molly grease. that slides better now.

Also, you say your disk was almost frozen to the tranny shaft. I have really been curious how people manage to tell that since the shaft HAS to come out of the clutch disk in order to disassemble the thing. Perhaps it didn't slide freely on the shaft once you had everything all apart? Mine has always slid freely once I got it apart, but there is no way for me to be sure that it wasn't somehow jammed on the shaft prior to disassembly.

I think I agree with you about the design tolerance being part of the problem. If I ever have to tear this thing down again (and I REALLY suspect I will be in there again!), I think I will take .050 or so off the aft end of the boss to give more room for the hub to move forward. It wouldn't be a problem if the disk wore faster because that would help the lack of adjustment at this end.

Do you feel that your intrinsic problem was the disk hanging up on the tranny shaft? I hope you get another 750 hrs or so out of this clutch job! I have about 900 hrs on my machine; the first clutch job wasn't needed until about 650 or so.

I am convinced I am doing SOMETHING to the clutch plates because of those measurements I made in a previous post. There was one of the old plates that nearly wasn't able to disengage the disk at all. The .4+" that it required is well beyond the travel that the throw-out bearing can have anywhere in its adjustment range.

I do appreciate your perspective on this tractor!

Terry

 

[BernieBenz]

The lack of lub that I found was in the disk spline on the tranny input shaft and the TO bearing hub guiding in the bell housing bore, not the sealed TO bearing itself. Yes, now that you remind me, there is a grease groove on the TO bearing hub. I drilled my relube hole thru the bell housing bore into this groove area. I don’t remember the O-ring but could be. Did this job a year or two ago.

The disk wasn’t frozen to the shaft as no trouble splitting but both showed signs of dry fretting corrosion, a lack of lube. Initially I suspected that the fork return spring was broken or weak but not a problem after the relube.

Both the disk friction surfaces and mating FW and PP surfaces were like new so just reused them, with no problems in the last 100 hours since.

Just bought new RI Ag tires for it, the optional size up, 6.0 x 12 and 9.5 x 16. Expensive, even on eBay, $460 total. Had reversed the wheels for a wider track so drilled a second tubeless valve stem hole in each wheel on the outside. Also makes it easier to fill rears with antifreeze.

Good luck with your problem! Happy New Year!

 

[Hooked_on_HP]

When you replaced the clutch the first time did you have the flywheel resurfaced. If so could they have taken to much off the flywheel.
Bill

 

[tosii2]

Bernie,
Thanks for the clarification on those points. I haven't seen any problem with any of the friction surfaces, even the original disk had plenty of wear on it, but I replaced it on general principles while I was in there.

I have my rear Ag tires with the wheel 'out' for max width also. Since my land is really hilly, I'll take any advantage I can get!

Bill, I haven't had the flywheel resurfaced. I have taken off the polish of it, but that hasn't shown any significant loss of material of the flywheel. It still looks quite flat with a straight edge.

As always, thanks for all the thoughts folks!

And Happy New year!!!

 

[boomer1025]

Just a guess, try putting thin shims (flat washers)between the flywheel & pressure plate. That should move the release fingers back. If that helps, then mike some washers so they are all the same thickness and use them.

 

[tosii2]

Boomer,

That would probably work as a 'for now' fix; what I have decided to do is to shim out the boss that limits the forward motion of the hub (throw-out bearing carrier) so that I can gain some adjustment that way.
I just wish I could answer the question as to why the fingers on the plates weaken so much over time!

Thanks for your thoughts!

Terry

 

[jones6780]

In your post with the photos of the jig mounted, I can see the clutch disk separating as you stated. I believe that is your problem. I have never seen a clutch disk expand in thickness as the pressure plate is released. I don't have a clutch disk to look at right now but if I remember correctly the rivets that attach the friction material go through all 3 layers. I mean that the rivet goes through the friction material, the center metal disc, and the friction material on the other side. A tight rivet will not allow the expansion that I saw in your photo.

Russell

 

[BernieBenz]

Not true IME, Russell. Only racing clutch disks are hard, automotive clutches are built with compliance to eliminate grab.

 

[tosii2]

In the disks I have taken out of the tractor, the front and rear friction materials are riveted to the cushion springs in different places (although you can see the backside of the rivets through larger holes in the friction material). The cushion springs have a bit of a 'wave' in them that is compressed when the clutch is fully engaged.
I didn't know all this stuff about clutches until I ran into this problem. One place I was reading claimed that the clutch disk is actually more complex to design (and perhaps to make) than the pressure plate.
If you have a spare disk sitting around, stick it in a vice and see how that cushion spring compresses. It isn't a lot, but helps make the clutch less grabby.

Again, thanks to everyone for the thoughts and suggestions!

Terry

 

[jones6780]

OK so clutch disks have a Marcel wave spring. I have not seen this on an Ag tractor that was built from 79-82. My 1700 does not have that feature. The info below came from, Selling Services: Providing Manual Transmission Clutch Replacement Service
If I read it correctly a warped clutch disk requires more travel to disengage. I personally would look for a clutch without the Marcel wave spring.

Clutch Disc Construction
When the clutch disc is closely examined, it痴 apparent that the hub is insulated from the outer disc by torque-absorption springs arranged concentrically around the clutch hub.

Because these springs cushion the throttle-on, throttle-off torque present during normal driving, they tend to wear or break under severe or abusive operating conditions. Next, the steel disc is divided into radial segments that resemble the blades of a fan. Each blade is usually waved to create a marcels effect that provides a small degree of compressibility (typically 0.020? between the two friction faces. This compressibility factor gives the driver a sense of 吐eel as the clutch engages.

Excessive marcel is usually caused by the rivets wearing into the lining or by poor manufacturing processes and will cause the clutch disc to drag against the pressure plate. This, in turn, will cause difficult gear engagement or hard shifting. Abusive driving habits, such as abrupt, high rpm clutch engagements, tend to loosen the rivets and cause the lining to detach from the disc assembly.
The riveting process provides the flexibility needed between disc and lining to make the disc compressible. As the disc is riveted, it must remain completely flat. Since even a minor warpage of 0.020 will cause the disc to drag against the flywheel and pressure plate, it痴 extremely important that the disc be manufactured, packaged and handled with care.
A simple way to test for disc warpage is to lay the disc on the new pressure plate assembly and then begin pressing around the edge of the disc with your thumb. If the disc tips upward at any point, the disc is warped. A small amount of warpage can be reduced by judiciously bending the disc over the knee. Obviously, this is an incremental process requiring patience. If too much pressure is applied or is applied in the wrong place, the disc can be ruined.