Ford 1120 Clutch

[BrisMatt]

I have a Ford 1120 which all of a sudden lost all drive. I was travelling down the driveway when it seemed to jump out of gear and free wheeled down to the bottom. The tractor is making a strange sound when I apply the accelerator somewhere near the clutch area, however if I apply the clutch and the accelerator the noise dissapears untill the clutch is released. I am also able to change the hi-low range selector without pushing the clutch in which would normally result in a grinding noise so I dont think there is any drive past the clutch. Does anyone know what this problem may be? I have pretty much conceded the tractor will have to be split to fix this.

Please see the attached video and listen for the noise when I press the accelerator.

By the way the tractor is hydrostatic and the clutch is used only to switch between high and low range.

Thanks
Matt

 

[BernieBenz]

I have an 1120, 820 hrs, with manual tranny. Several years ago now I was having clutch problems and out of adjustment. So I split the tractor and found that the problems were just lack of lub on the clutch disk spline and the long tranny input shaft where it goes thru the bell housing in an unlubed tight fitting hole. Disk, pressure plate, and throw out bearing were all good so were reused. I drilled a hole into that bell housing area and added a zerk fitting so that I could relube that input shaft point from underneath.

On splitting the tractor, after removing the bucket I did it by myself without a lift with wheels on the ground, concrete garage floor, and a couple of floor jacks to stabilize the two halves. Each half was pretty well weight balanced over its wheel pair. Lots of stuff to drain and unhook before the split.

 

[BrisMatt]

thanks Bernie,

Well I took a gamble and split the tractor between the transmission housing and the clutch housing. I did this because after some research I though it was a hydrostatic transmission issue as thats where the noise seemed to come from. Well from the outside the hydrostatic pump seems ok, the noise sounded to me like i might of stripped all the teeth on the front of the input shaft, but they are all fine.

However, when I poke my head in and look up into the clutch I see, the following items shown below. I know nothing about clutches so is that the release bearing hub I am holding up with the screw driver, it appears to fit onto the fork but at the moment its disconnected.

Also there appears to be damage to the coupling that the transmission input shaft fits into. Its a bit loose and of the 4 teeth around the perimeter 1 almost appear broken so it isnt a very tight fit.

Does any of this look broken, and be the cause of the loss of drive??
Thanks Matt

 

[BernieBenz]

Hi BrisMatt,

It appears to me that you have a failed clutch throwout (Ford calls it a release bearing).
If so, and to get at the clutch components, you have split the tractor in the wrong place. Go back and split between the engine and bell housing.

According to the Ford 1120 / 1220 repair manual, the clutch system is the same, identical for either the HST or the MT trannies. The throwout bearing is pressed onto a sliding hub which is moved by the cross shaft fork to engage the pressure plate fingers. FYI, my throwout bearing is a NSK 24TK308B2 V3, which is Ford part number SBA 398560110.

Inasmuch as the clutch system is lightly used with the HST relative to that of the MT, I would expect that the rest of your clutch system components will be in good shape and fully reusable. Just relube the obvious places, disk to input shaft spline and the sliding hub to tranny tube, which was my problem.

Let me know if I can help further, with parts, part numbers, repair manual pages (I will have to borrow a scanner to copy pages for email).

Regards, Bernie

 

[BrisMatt]

well I pulled the hydrostatic unit out and it turns out it was a broken spline. On the output shaft there is a coupling and the teeth on that were completely stripped, so was the teeth on the shaft, hopefully that can be replaced. It does kind of make sense, when the damaged occured I heard some metal shearing and now when the accelerator is applied you get a sort of crunching sound. Here is the photos below

I had a friend look at the clutch and he agrees it needs replacing, the internal coupling on the disc is loose and not far from breaking so I will also replace the clutch disc whilst I am at it. No doubt if I left it in its current state it would fail a couple of hours after putting it all back together.

Thanks for your help.

 

[BrisMatt]

I have pulled the broken shaft out of the hydrostatic unit.

Its about $600 by the time I get it to Australia!
Hopefully someone can repair it, I have been looking at a few websites and apparantly you can fix these things.

 

[BrisMatt]

I am having serious problems trying to join the tractor back together. The input shaft needs to fit snuggly into the release bearing (photo above) then the splines into the clutch. I can seem to get it to fit through the bearing. Having split it on grass rather than flat concrete was a mistake.

How do you keep the bearing still? mine as you can see is not fixed to the forks in any way and if the input shaft hits it can drop down.

 

[BernieBenz]

No suitable photo above, but No! The release bearing, mounted to its sliding hub and attached to its cross shaft release fork, is a greased slip fit in the bell housing and does not touch the input shaft, thus not involved with the input shaft engaging the clutch disk splines and pilot bearing. What’s wrong? The disk must be centered on the flywheel when you bolt up the pressure plate or it won’t line up with the pilot bearing. Is your release bearing pressed onto the sliding hub? Sounds like it is just hanging loose.

 

[BrisMatt]

Thanks Bernie, I have not really touched the clutch so hopefully it is all aligned properly.

My problem I guess is I have split the tractor where the transmission is, not where the clutch is so I am unable to easily slip the hub and release bearing over the input shaft as I cannot reach into the clutch area. So I have been putting the realease bearing and hub inline with the clutch disk splines then pushing in the clutch pedal to jam it against the pressure plate hence keeping it in place whilst I insert the transmission and input shaft. Is there another way to keep the hub and bearing perfectly aligned in the correct position as I join the tractor together? The input shaft (not the splined section but behind that) is about the same size and the hole in the centre of the hub so it needs to be spot on then I need a way to hold it in place whilst I join them together.

 

[BernieBenz]

I assumed that you had resplit the tractor between the engine and the bell housing which is what I believe you must do to work on the clutch release mechanism and release bearing sleeve.

The repair manual implies that the clutch system is the same for 9x3 and the HST trannies. But apparently not so with respect to the clutch bell housing and the release bearing sleeve details, judging by your pics and my cross sectional view of the manual, 9x3 clutch system. The main diff of interest for you is that on the HST version the release bearing sleeve slides on the OD of the HST input shaft housing, not in the ID of a bore in the rear of the 9x3 clutch bell housing.

Thus, you must split the HST clutch bell housing from the engine and reinstall it back onto the HST rear extension housing with the HST installed, in place. That done, you can then install the clutch release sleeve with release bearing on the HST input shaft housing which will be now be extending into the clutch housing. Don’t forget the release sleeve return spring.

What a Job, Good luck!