[Black Isle Snapper]

I have a Ferguson TEF 20 and am trying to couple up a small topper, but it is simply destroying the PTO adaptors.  Will an overrun coupler help to solve this problem and how does it work? 

[stufe35]

I am assuming the adaptor you are using is one of the thin shim types that fits over the shaft on the tractor and then the shaft of the mower fits over it.


They are subject to wear as they are very thin and there will always be some movement in the connection.

An over run adaptor will help make sure you buy the right sized one.  Female end of adaptor to suit the tractor , male end of the adaptor to suit the topper. No thin part to wear out and the added benefit of the overrun. This is what you need:


https://www.ebay.co.uk/itm/Ferguson-T20-TE20-Tractor-PTO-Shaft-Over-Run-Clutch-Coupler-Converter-Overrun/222256238604?hash=item33bf81100c:g:ElkAAOSwa8dZ1zqx

This im guessing is what you have now ?

https://www.ebay.co.uk/itm/FERGUSON-TE20-TEF-TEA-TED-TRACTOR-PTO-SLEEVE-INCREASER-ADAPTOR-56mm/181791243837?epid=22003676028&hash=item2a539a3e3d:m:mi_C7UIfkF37aJxdbcukosg

You need to be careful because of the extra length the coupler introduces.  You may need to shorten your pto shaft on your topper slightly.  This can easily be done with a hack saw.  Test the length by  setting the height of your topper such that the pto shaft is dead horizontal...ie at its shortest.  Check you can still press the button and pull the pto back by 20mm or so; thereby demonstrating there is suffiecient play in the shaft.

Hope that makes sence if not ask again

[UPoneacre]

Just as a precaution I'd always fit an over-run coupler when using a topper on a TE20, particularly. Without it you acn find that coming to the end of a run, slowing down the tractor, then finding that the rotating topper blade is trying to drive back through the pto pushing the tractor forward; particularly unnerving if you're working down slope. The overrun coupler will eliminate that.

I don't know what sort of ground you're working over but if it's rocky or there are large clumps that might stop topper blade/pto shaft rotation you risk clutch damage on the Fergie. If that's the case then it's worth fitting a slip clutch at the topper end of the pto shaft to avoid it. Your local ag engineers will be able to advise or you can find one by web search.

[stufe35]

Toppers often have a shear bolt to provide the protection mentioned above. Worth checking if yours does and making sure you have some spares.

[Black Isle Snapper]

Many thanks to all who replied. I have now ordered an overrun coupler and a new pto shaft in the inch and three eighths size. So am hoping this will solve the problem.
Cheers, Black Isle Snapper

[stufe35]

Why the new larger pto shaft ?

And have you ordered the right overrun to match ?  (Not the one I put a link to)

[UPoneacre]

Fitting a 1 3/8" pto shaft is straightforward but there is sometimes a problem with some replacement units where the new pto shaft end cover (which houses the bearings) hasn't been machined to the same dimensions as the original. It's a common problem, as I found with a Sparex unit, so worth checking the new one against the old one before fitting. In my case the outer machined length fouled the lower retaining bolt boss in the axle casting and we dealt with it by some careful grinding of the boss after stuffing the housing full of rags to prevent the grinding dust getting in, and then cleaned it out thoroughly afterwards.