Dexta Live Clutch Warning

[Brian]

Fitting a new live clutch to Dotty is not a hard job as I have done these many times over the years. I always recommend that, at the same time as a clutch is fitted the thrust and pilot bearings at least should be replaced. This is where the problems started on Dotty.

I got a new clutch and bearings from Malcolm Hipperson which, according to the parts book, (and other aftermarket parts suppliers which I subsequently checked), were correct for the live drive tractor.

When I came to install the thrust bearing I noticed that the new bearing was a lot slimmer than the one I was replacing. Putting this down to redesign I went ahead and fitted it onto the hub but, once on, it did not look correct at all, the hub protruded through the front of the bearing beyond the bearing thrust surface.

I placed the bearing/hub assembly on the forks of the new clutch and discovered that I could spin the bearing without it touching the thrust surface, the fingers rested on the inner race of the bearing not on the thrust bearing surface. If it had been fitted the fork adjustments would have been worn off or the hub itself would have worn away.

The new bearing did not have the thick thrust surface that covers the front of the hub, it was a thrust bearing for a Ford 3000 that has a totally different thrust finger set up.

I took it back to Malcolm and he got straight on to the supplier who says “Yes, we know about the problem but cannot get a bearing to meet the original specification”!! I suppose they are happy to sell many more live clutches after the thrust surfaces have been worn away by the wrong bearing.

Malcolm was very apologetic and helpful, he found me a bearing with a thrust surface and although it is narrower than the original, I can fit a 2mm spacer behind it on the hub to bring it out to the same position as the original.

It is highly likely that other suppliers are supplying the wrong thrust bearings with their clutches believing it is the same as the 2/3000 so please check closely when fitting a new clutch assembly.



The old bearing with its thrust surface.



Check the thickness of the thrust surface, this covers the end of the hub.



Note the difference in the thickness of the new and old bearings.

[Bensdexta]

Brian,
Does this problem only apply to Live Drive tractors?

[Brian]

I have not checked a standard clutch Ben, it showed up with Dotty and she is a Live Drive but I suspect it could be the same in a standard clutch.

[Brian]

Further to Ben's question, I have a new live clutch bearing and hub from a Super Major from my days in the dealership. The bearing has a similar thrust plate to the Dexta and I would suspect similar problems would occur if a bearing as I was originally supplied, is used.

Well, Dotty is back together and running and the starter sounds a lot more healthy, even with my welded and re-cut and filed teeth. Took me a day just to do that.

I do not have a lathe so I went “diving” in my neighbors scrap bin and found a nice solid suspension bush from which to make my spacer for the clutch thrust bearing. This bush fitted exactly over the thrust hub and back onto the un-machined part behind the bearing surface which has worked out quite well.



I used trial and error to find the right thickness and used the criteria of the thrust plate to hub clearance that I measured from the original bearing. The spacer finished up as 11mm wide but this will differ if you spacer on the bearing surface of the hub. It might need to be about 8 mm there. The 11 mm has given me a clearance of around 1 mm from hub to the inner surface of the bearing thrust plate.





It fitted well and once back together, I am quite pleased with the action and position of the clutch pedal. Had I used the original bearing supplied I suspect the clutch pedal height might have been higher and , in PTO mode, nearly impossible for an old chap like me, to get my foot on the clutch in a hurry.

I have also had the radiator serviced so she should run cooler on the bush cutter when I get back into the “wilderness” that is the 15 acres of woodland I look after.

[chrism0dwk]

Brian,

Would you be able to give us the dimensions of both the old and new thrust bearings so we can identify "wrong" parts?

Thanks,

Chris

[Brian]

Old thrust was 25 mm from front of thrust plate to rear where the bearing meets the hub. New one is 17 mm measured over the same distance.



The replacement first supplied was 18 mm so, when fully on the hub, the hub protruded through the bearing and this was what was catching on the clutch lever adjustment buttons. The actual thrust bearing did not rest on the buttons and could be spun freely when the bearing/hub was rested in position.

[chrism0dwk]

Superb, thanks. Interestingly, the workshop manual stipulates 28.45mm (ie 1.12") length, though I notice Agriline claim to be selling a 22mm one.

I was worried that my clutch is currently fitted with one of these "thin" bearings, because every time I adjust the clutch linkage clevis so that the PTO just stops when the pedal hits the footplate, it appears to need adjusting again after half an hour spent mowing the paddock. Having said that, I'd expect a loud screech from the clutch if the hub were to contact the release fingers...

I expect I'll end up splitting my SD soon, though it's a complex business because the FEL's got to come off first

Chris

[Nick]

Ive just come accross this problem myself, I need to replace the thrust bearing on my live dexta, is the bearing pressed onto the hub? Are any parts suppliers selling the correct bearing or is the 22mm the only one available?

[agroman]

Ah interesting thread!
Mine is part way through a total rebuild. Live clutch needs replacing part of the reason for the split, rebuild. Does anyone know where we can source a correct size thrust bearing. Can you still get a FNH genuine one? I will need to look into this when I get closer to the clutch, as it has a loader the clutch takes a lot of work!

[ianpdexta]

Thanks Brian for posting this information, and the rest of the thread. I too will be reassembling my Super D with a new double clutch between now and Christmas, I was temped to use the old bearing because it seems very smooth but your mention of the pedal being very high rings a bell. The pedal was uncomfortably high on PTO setting so it might be that there is a thin bearing in there already, someone else has definitly been in there playing about before me.

I guess there is a pedal height setting in the manual which I have to admit I haven't yet taken the time to look up.

Regards

Ian