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Rotoflex Rear Hub Bearings


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8 hours ago, griffipaul said:

Resurrected thread cos about to put longer m12 rear studs in roto rear hub and anticipating having to remove rear hub as I will not drill hole thro backplate

Why not?  Very much easier than pulling the hub and allows easy swapping in the future.  Hole only needs to be big enough to pass the  head of the stud and doesn't weaken the backplate.  You can fit a grommet if you wish but mine have been open for at least 15 years with no ill effects. 


You won't get the LR M12 studs in without one or the other.



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Pete Lewis now look what you've made me do.

Did the hub come off by hand......nope

Have I got a puller ......nope.

Can I improvise ...yep

Did I get it off yep.

Did it come off on its own .....nope ....It came off with brg and oil seal.

Will worry about putting it back together later

Oh yes and found another cracked Cosmic alloy....one good one at the moment just one to go.




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It sure did , always wary first time working on iners of rotoflex hubs , think I understand them now. Replaced roto couplings a few years back when I refurbed the rear end ,was not as bad as I thought , used Nigel Clark out of a mag method.

As always good advice helps first time around.




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So one side went fine , all back together with new studs. But the otherside is fighting back.

Hub is stubborn , wont budge even with 3 leg puller, all that is happening is its pushing the outer drive shaft back in distorting the roto, worried in  case do more damage.

Any suggestions ? 

Last resort is to pull off vert link assy with shafts , push shaft through and attack hub from the rear ,


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Tried wedging bar between inner ond outer spiders which is what I must have subconciously done on the otherside and discovered that the f.....ing roto has sheared. So it Is off with the lot. Just goes to show that a little knowledge is a dangerous thing. Only replaced them 2 years ago . Boll.....s

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  • 2 weeks later...

All off and stripped down,  some observations. Considering spline had moved freely on hub sufficient to push roto back only a few days previously it still took some effort on the puller to pull hub and vertcal link assy off the shaft , hub came out of link ok with a drift from the inner side . Rotoflex had sheared at the core and debonded at the trasverse metal plate. Interestingly I bought the couplings a couple of years or so back when the club were pushing Firstline as the new supplier , but looking at them now they are marked as G M which are the same as the new one I bought from Fitchetts, which are alledgedly not good quality. Club have  not advertised rotflexes from anybody for a while. So are Firstline G M in disguise or were they old stock. 

Shaft has .148 spacer worn by about a thou and no shims.

Hub slides on splines ok til engages with shaft dia then its tight , how much load should it take to push all the way home. Not forcing it at this stage

Nothing obvious visually . Want to make sure everything it right before swopping studs and checking bearing float cos that will involve buulding and stripping a few times.

Relevant photos attached 



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