Thread: A stronger Rotoflex possibility.

Nice work Simon! Cheers

Originally Posted by Slunnie

The bushes in this look very much like those in the coupler for the drum in my Case header, which has 6 bolts for the drum and has a spline in the centre for the gearbox shaft. However the bushes don't tolerate much flexing due to having only a small amount of flexible material. I replaced many bushes and couplings due to the bushes being destroyed by a slight run-out of the drum mounting face before replacing the $10K drum during last year's harvest.

I suspect there would be far too much flex in the D2 to use this style of coupling that's probably OK where there is not much suspension movement.

You're probably right Graeme. That part is from a Pontiac GTO and designed to replace the rotoflex off the gearbox which if like the Commodore goes into a fixed propshaft.

With some more searching using GKN part numbers, it seems people have been on to this already!

Here is the low down, especially for the fans of GKN parts.

LandRover standard Rotoflex (30mm) GKN P/N:249782

GKN 35mm Rotoflex to suit GKN P/N:249537.

To do this the bolts also must be changed from M12x65 to M12x70 with a recommendation of high tensile and zinc plate.

Apparently, apart from the bolts there are no other problems from what I can read.

http://forum.landrovernet.com/archiv.../t-166764.html
http://www.landroversonly.com/forums...-donuts-38013/
https://www.landyzone.co.uk/land-rov...warning.82257/

https://discoweb.org/forums/newreply...reply&p=976369

Originally Posted by listerdiesel

OK, here are the details of the available parts:

1) Genuine LR part has 'GKN' '249782' 'GAG1' moulded (molded) into the rubber. It is relatively flexible, you can grip two of the moulded pads and bend the coupling. There are voids in the heavy pads that go all the way through the coupling.

2) Pattern part, sold by Allmakes, no identifying marks at all, dimensionally similar to the LR part, there are voids in the heavy pads but they are not all the way through. The coupling is almost solid and not able to be bent by hand.

3) Heavy Duty part, sold on ebay, is made by GKN and has 'GKN' '249537' and 'GAJ1' moulded (molded) into the rubber. It is 5mm thicker than the standard coupling, has no voids at all in the thicker pads and is not able to be bent by hand. The ribs between the pads are increased thickness as well.





All three have the arrows for marking the bolts, the Allmakes one looks as though they have used an actual coupling to make the mould with, the arrows are not very well defined, while the GKN ones are sharp and clear as you would expect. The heavier coupling requires longer bolts, stock bolts are not long enough to fully engage the locking portion of the nuts. Stock bolts are M12 X 65, you need M12 X 70 to use the heavier coupling. They will just fit in behind the pinion flange.

Considering how relatively soft the LR part is, I'm not surprised that the heavier duty coupling has lasted so well on my own vehicle, but we do go off-road as such, but do tow a lot.

My own coupling was checked recently, still solid with no cracks, and I have a spare, so won't be looking to change anything soon.

The lack of ID on the Allmakes component does suggest a 'Far East' source, but is seems solid enough to do the job.

Hope this is of some use to anyone looking at spares.

Peter

Sorry about my ramblings here.

Ensure the rotoflex is reinstalled in the correct direction - it looks like it has different characteristics or strengths depending on how it is installed.

The arrows on the sides point to the pinion flange or the tailshaft flange - dont clock everything around by a bolt hole otherwise everything changes, the compression parts of the rotoflex go in to tension and the tension parts go in to compression.

I honestly dont think a thicker unit will last much longer, its the extra flexing from a big lift and articulating that cause them to split.
On a stockish vehicle they last for years.

Originally Posted by loanrangie

I honestly dont think a thicker unit will last much longer, its the extra flexing from a big lift and articulating that cause them to split.
On a stockish vehicle they last for years.

On a Disco2 the angle through the rotoflex doesn't change much with a lift due to the suspension geometry. Big tyres and care free driving kills them in this case. But if you do have lift they absorb a lot of driveline vibration which a uni joint doesnt do.