Power Major Clutch Won't Disengage.

[whirly]

We have been doing some upgrades on the old man and had pretty much finished. Yesterday I pulled it out for about an hour to check the breaks and new power steering and everything worked as expected so I pulled back into the barn and shut down for the day.

This morning I hooked up the mower; disengaged the PTO; made sure it was out of gear; and started the engine. Fired right up as always. Let off the transmission break and pushed the clutch full in but when I tried to put it in gear it just started to grind. PTO also will not go into gear with the engine running and the clutch full in.

Checked the linkage for obvious damage and made sure there was no interference underneath. Everything looks proper.

Anyone have an idea what the problem might be? Is it time to split the tractor?

[oehrick]

Hi Whirly

Did you run the mower up to speed and then declutsh and try to put into gear straight away ? If so the inertia of the rotating mower parts can keep the PTO turning for quite a while as it runs down*, so there will be shafts turning in the gearbox (even if the clutch is dipped) which will not let you catch a gear.

If you have a live drive, 2 stage clutch I'm not sure if thus is the case or not - but someone will be along soon who does

Hope its operator unfamiliarity rather than a problem......

* can also be embarrasing if you need to stop in a hurry I'm told

[whirly]

I do have a Live PTO (2 Stage Clutch).

Are you asking me to start the engine with the PTO and Mower engaged; bring it up to PTO Speed; push the clutch in and shut the engine off?

[Brian]

Bit strange that PTO clutch and main clutch are giving the same problem, they are two different parts of the clutch with separate linkage, plates and springs. The only thing that connects them is the clutch thrust bearing and the linkage to the clutch pedal. There are pins on the clutch cross shaft to the thrust bearing fork that may have broken.

Any chance of something like condensation/cold weather has frozen the plates to the clutch unit?

If you can get in a clear, open space I would be tempted to start the tractor, in gear with the clutch fully down and my hand ready on the stop cable, to see if that clears it.

I get the PTO stuck on Dotty occansionaly but with the brush cutter fitted and starting at low revs, the uneven rotation soon clears the problem.

[oehrick]

As Brian said - I've no direct experience of live drive to add anything further.

[whirly]

Any chance of something like condensation/cold weather has frozen the plates to the clutch unit?

Brian -
Cold temps are not an issue. Here at 19° above the equator the minimum temp we get is 53F (12C) but our low for the last few days has been in the mid to upper 60's (18-20°C).

It's in the barn facing out so I'll try starting in 1st with low RPM and see what happens. Yes, I will have a firm hand on the shutoff cable. This is going to be like a rodeo.

oehrick -

Thanks for your input. It looks like you had the same idea Brian has about trying to "break the plates loose". It's worth a shot.

[whirly]

oehrick

You were half right on the operator error. I started it with the PTO lever in the disengaged position. I first tried put the tractor in gear and couldn't. So I tried the PTO lever and got the same grinding sound so I assumed neither clutch plate was disengaging. I forgot that the PTO clutch keeps the gear turning after you put the pedal down until the clutch plate looses momentum. This morning I started out of gear with the clutch pedal down and the PTO engaged just fine.

Brian

I started as above in gear - no Joy. However, it just occurred to me that revving the engine up and down might help so I'll try that as soon as it stops raining. If that doesn't work ... is it split the tractor?

[oehrick]

Not quite Whirly, I was more concerned about the stored energy in the mower turning the gears even if the clutch disengaged, I don't think that is an issue with the live drive but can't be sure. I think Brian is likely to have you zeroed in on the right area.

[whirly]

Brian - You wrote:

The only thing that connects them is the clutch thrust bearing and the linkage to the clutch pedal.

If I remember correctly, as the clutch pedal is depressed it first disengages the drive clutch and then the PTO clutch. So if the PTO disengaged properly the problem is after the thrust bearing. In other words, inside the clutch housing - correct?

[Brian]

Drive should disengage first, PTO when you get close to the bottom of the travel.

Reving will not free it if the plate is stuck, you have to drive around with the clutch down and keep hitting the brakes, If this does not work it is likely that one of the drive plate levers has broken or the pivot pin dropped out meaning that one of the three levers is not freeing the plate.

This is then a splitting job and a time to take out another mortgage. If the clutch cover or any other part of the clutch itself, other than the plates are worn or damaged they are impossible to find. Although it can be done without it the clutch also needs a special tool to assemble, rebuild and reset it.

A new clutch is available from Agriline but it costs around £750.00.

[whirly]

I'll try the break thing with all my parts crossed for luck.

If that doesn't work, I didn't see a complete dual clutch on Agriline but they have an "improved cover plate assembly" which if it replaces all the springs, fingers and other dooda's would make the rebuild a lot easier.

I have the mortgage broker on the line now!

[j.myatt]

I had a single stage clutch on a power major wouldnt disengage, eventually split tractor and found the clutch was fine but the pressure plate arms bent, put it down to the bushing on the clutch arm (east-west) had moved down the shaft so one side had no bushing and my opinion the thrust bearing wasnt square to the pressure plate?

Only a thought

[58vintage]

Whirly,

I have the new type modified 2 stage clutch from Agriline. Everything looks more resistant to wear and damage, It's great I've put about 40 hours of mixed work through it, ploughing, topping with 6ft and 9ft mowers, on our big windrower and road work with a trailer on. Much easier to set up than the original pretty much goes straight in out of the box. If they don't do a kit yet you will need to by a pilot and thrust bearing to, but they are a couple of pounds extra.

Regards,

James.

[whirly]

James -

Thanks for your input. Did you buy the complete clutch assembly or did you just get the clutch plates, bearings and front cover?

You are right, the new cover plate looks like much less trouble than the old one. I asked if they had a complete assembly and they told me they did not. The cost of the parts is just over £600 which isn't that much. So my only concern is aligning the clutch plates properly without the fixture.

Anybody have a how-to on aligning everything without the fixture? I haven't found one yet.

[whirly]

58vintage -

That is what I'm hoping but splitting the tractor in the field is a pain and the clutch is original. So even if the clutch still has some life left in it, once it's split I might as well do the clutch too.

[FPW501]

Hi!
I have used the driveshaft/shafts on the gearbox for aligning the clutch, an then I putted them back in the gearbox. You would probably remow them anyhow to renew the oil seals when you have the tractor split in two. This way of doing the job was functional enough for me!
// Martin

[Brian]

On a live clutch unit it is assembled on a jig so no lining up tool is required.

I very rarely use a tool on clutches, even the double clutch on 3000 s and my Nuffield, just line them up by eye. This works on any clutches as long as you are careful and get everything central.

[whirly]

Thanks Martin and Brian.

Sounds like it's not as daunting a task as I had originally thought. Probably a lot easier with the new version of the Cover Plate.

[Brian]

The new clutch should be a pre-assembled unit with both plates fitted. It just bolts onto the flywheel as the flywheel on a live clutch has no place for the drive plate to run like a normal clutch.

[whirly]

The new clutch should be a pre-assembled unit with both plates fitted. It just bolts onto the flywheel as the flywheel on a live clutch has no place for the drive plate to run like a normal clutch.

I emailed Agriline about that and was told the "Improved Dual Clutch Cover Assembly" IS pre-assembled, so no fiddling with fingers, springs and setting tension, but it is just the cover plate not the complete clutch assembly. If you know where I can get a complete pre-assembled dual clutch assembly with both plates fitted, I would really appreciate a link to the seller.



Here is the reply from Agriline:

Code: Select all

Good morning

Thank you for your recent query regarding your Power Major dual clutch.
We currently do not list a full kit to replace the dual clutch on your model of tractor, but we do sell the parts to do so.

Having a look through he parts catalogue, C0095 is an improved version of the original, and has all the parts associated with it including the fingers and such.

If you wanted to purchase that, and add the 2 plates, I would also suggest new bearings to go with it. All of the parts are in stock ready for dispatch.

I hope this information helps, and I look forward to your response.

Kind Regards,
Stephen Bennett
Sales Technician

Or am I missing something here?

[Brian]

In the picture you can see the plate installed, it must come with the twoplates installed as I said, the flywheel has no surface for the clutch plate to work on.



Although not the complete flywheel ( ) you can get an idea of the hub in the centre and the thickness of the metal itself. The live clutch is a self contained unit with the plates fitted internally the the complet unit bolts onto the flywheel.

[whirly]

Brian - Thank you for the tutorial

I think the light went on.

[shepp]

If your clutch was operating correctly before the tractor was laid up, then the problem of the transmission clutch not disengaging is likely to be something as simple as the transmission plate stuck to the flywheel, or the pilot bearing in the flywheel centre seized up. When plates get stuck to the flywheel sometimes no amount of shock treatment will free them. I remember once splitting a problem tractor that we had run for hours with the pedal depressed and tried all the shock tactics, the clutch cover was removed, the transmission drive plate was stuck to the flywheel, but as I moved a few yards to place the cover on the bench I heard a clatter and looked round to see that the plate had detached itself and dropped to the floor! *******! A quick clean up with emery cloth and re-assembly and it was fine. Might not be as expensive as you fear!

[Brian]

Problem is, on a Live Clutch the plates are not on the flywheel, the clutch is a self contained unit and to free it off, if it is stuck, it will have to be completely dismantled.

The pivots are in an aluminium housing which after 56 years is most likely showing the strain.

Hopefully it is just a stuck plate but, knowing that clutch, I fear it is not.

[shepp]

Yes of course you are right Brian, I should have said stuck to the cast iron carrier not flywheel. The picture that immediately sprung to mind was the MF35 that we had the issue with, on those clutches the PTO drive plate is built into the cover, the transmission plate is a free assembly, and it was that plate that had stuck to the flywheel. As you say the Major dual clutch is not a particularly robust assembly, with the aluminium "spider" cover, and when I first read some time ago about the "improved" cover available from Agriline I was intrigued. Has anyone any experiences to report about this improved cover?
An issue that I had some years ago with my Power Major - which I have known from new and have owned for a long time and which has only done 2800 hours from new - was that the impregnated lubricant in the bushes between the outer PTO dive shaft and the inner transmission drive shaft dried out, causing the two shafts to bind together and rotate as an assembly. This meant that when the transmission first stage of the clutch was de-clutched, the second PTO stage continued to give drive to the transmission shaft so that the tractor continued to move! A bit alarming! A dis-assembly, clean up of the bushes and soaking in hot oil for a long time and then allowing to cool to soak up the oil did the trick!