Discussion
Is it not due to the drive shaft being the top wish bone?
They are fairly large bearings and i think they will take a lot of pressure proberly due too the wider wheels we run on these cars, it will impose a twisting torque on the hub.
I know where you are coming from with the figures, they seem very high but my Jag xj40 requires the rear hub to be FT as the drive shaft is the wishbone too.
I know when i did mine the bearing and drive shaft rebuild they were was play at 200ftlb, I have a torque rachet that goes too 250ftlb
Cambelt
They are fairly large bearings and i think they will take a lot of pressure proberly due too the wider wheels we run on these cars, it will impose a twisting torque on the hub.
I know where you are coming from with the figures, they seem very high but my Jag xj40 requires the rear hub to be FT as the drive shaft is the wishbone too.
I know when i did mine the bearing and drive shaft rebuild they were was play at 200ftlb, I have a torque rachet that goes too 250ftlb
Cambelt
I think it's due to the size of the nut, compared to the wheel nuts, larger nuts need more torque for the same force.
Also due to its size and weight and speed of rotation, they can and do come loose.
Over tightening though can damage the washer which provides some spring effect, I'm sure this is the reason my last new one came loose.
Also due to its size and weight and speed of rotation, they can and do come loose.
Over tightening though can damage the washer which provides some spring effect, I'm sure this is the reason my last new one came loose.
So perhaps it is something to do with what I first hinted at, stretching the shaft to cause spring effect. Or as you say leigh, the crush washer gives the spring effect too.
Still sounds like overkill though. I had a single sided swing arm Ducati 916 that had a similar size nut, more power to weight than the Tiv, fitted with a taper bearing that couldn't be overtightened. 35-40ftlb IIRC. Granted it wasn't on a drive shaft but it was all that was holding the drive wheel on.
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Maybe I shouldn't try to understand
, I should just do as the books say 
Still sounds like overkill though. I had a single sided swing arm Ducati 916 that had a similar size nut, more power to weight than the Tiv, fitted with a taper bearing that couldn't be overtightened. 35-40ftlb IIRC. Granted it wasn't on a drive shaft but it was all that was holding the drive wheel on.
Blatent picture upload of my 2nd favourite toy
Maybe I shouldn't try to understand
, I should just do as the books say TOPTON said:
So perhaps it is something to do with what I first hinted at, stretching the shaft to cause spring effect. Or as you say leigh, the crush washer gives the spring effect too.
Still sounds like overkill though. I had a single sided swing arm Ducati 916 that had a similar size nut, more power to weight than the Tiv, fitted with a taper bearing that couldn't be overtightened. 35-40ftlb IIRC. Granted it wasn't on a drive shaft but it was all that was holding the drive wheel on.
Blatent picture upload of my 2nd favourite toy
Maybe I shouldn't try to understand, I should just do as the books say
I would have thought it uses a lighter weight nut, but it would be threaded the wrong way to the rotation. so would not need to be tight, as pointed out ideally one of them should be a LH thread, as it's only one side that comes loose.Still sounds like overkill though. I had a single sided swing arm Ducati 916 that had a similar size nut, more power to weight than the Tiv, fitted with a taper bearing that couldn't be overtightened. 35-40ftlb IIRC. Granted it wasn't on a drive shaft but it was all that was holding the drive wheel on.
Blatent picture upload of my 2nd favourite toy
Maybe I shouldn't try to understand
, I should just do as the books say on some of the very early cars with wheels that used a single spinner hub nut, they used RH thread on both sides but noticed that these also came loose.
Iv'e been in the garage today and was looking at a spare drive shaft, after measurement I can tell you the crests of the thread measure at 22.06mm and the pitch is 20 TPI. The thread is therefore 7/8" UNEF! You could try a M22x1.25P, IF you do manage to fit it it certainly will never come loose 
I agree with Leigh that the washer behind the nut is often damaged (unless you make one from tool steel ), deformation of this washer would lead to the nut effectively becoming loose.
The reasonably high torque setting is not due to the size of the nut, the fact it 7/8" just means it can withstand more torque than lets say an 1/8" thread of the same pitch and form. The 220lb/ft is the torque required to put enough stretch (within it's elastic limit) into the drive shaft to stop further movement in the assembly in operation.
Chris.
I agree with Leigh that the washer behind the nut is often damaged (unless you make one from tool steel
), deformation of this washer would lead to the nut effectively becoming loose.The reasonably high torque setting is not due to the size of the nut, the fact it 7/8" just means it can withstand more torque than lets say an 1/8" thread of the same pitch and form. The 220lb/ft is the torque required to put enough stretch (within it's elastic limit) into the drive shaft to stop further movement in the assembly in operation.
Chris.
Having said that, I always assume the 220lbf applies to when fitting a new bearing, that beds in and relieves some of this tension.
When re-torquing an existing bearing I generally use around 140 lbf. I have found over time that going to 220 on an old bearing causes more trouble than it's worth.
When re-torquing an existing bearing I generally use around 140 lbf. I have found over time that going to 220 on an old bearing causes more trouble than it's worth.
Got sorted and its's up and running again. (obviously because I started a thread about visiting a weigh bridge) The threads on the end of the drive shaft were pooped so I had to cut about 5mm off
.
This is the length required for the nyloc on the nut to work, so interestingly I also cut that part off the nut. double
The nut now sits flush with the end of the drive shaft , but this time it is thread locked on with a split pin through them both. Torqued up to F in tight with a 4ft bar.
I have marked the nut/shaft with paint to keep an eye on it for any movement. Was giving it big bootfulls before and everything is fine so far. But I am sure it won't move
. This is the length required for the nyloc on the nut to work, so interestingly I also cut that part off the nut. double
The nut now sits flush with the end of the drive shaft , but this time it is thread locked on with a split pin through them both. Torqued up to F in tight with a 4ft bar.
I have marked the nut/shaft with paint to keep an eye on it for any movement. Was giving it big bootfulls before and everything is fine so far. But I am sure it won't move
TOPTON said:
Got sorted and its's up and running again. (obviously because I started a thread about visiting a weigh bridge) The threads on the end of the drive shaft were pooped so I had to cut about 5mm off.
This is the length required for the nyloc on the nut to work, so interestingly I also cut that part off the nut. double
The nut now sits flush with the end of the drive shaft , but this time it is thread locked on with a split pin through them both. Torqued up to F in tight with a 4ft bar.
I have marked the nut/shaft with paint to keep an eye on it for any movement. Was giving it big bootfulls before and everything is fine so far. But I am sure it won't move
What spec and size nut did you settle for in the end - and where did you get it from? . This is the length required for the nyloc on the nut to work, so interestingly I also cut that part off the nut. double
The nut now sits flush with the end of the drive shaft , but this time it is thread locked on with a split pin through them both. Torqued up to F in tight with a 4ft bar.
I have marked the nut/shaft with paint to keep an eye on it for any movement. Was giving it big bootfulls before and everything is fine so far. But I am sure it won't move
A kind PH gent PM'd me and offered 2 nuts for beer tokens. So the spec is still unknown exactly but they are available from http://www.rtracing.co.uk/ I've been told earlier.
Also any Jag dealer should have them for an 1980s XJ6/12 my research tells me.
Also any Jag dealer should have them for an 1980s XJ6/12 my research tells me.
to anyone in a public place, there is laws to stop things like that ya know 
once you get close to 200lb you can then adjust to the next slot on the castle as its only going to be 60 degrees between slots. as said it's best to slightly under torque if the bearings are not new.
Also I find it easier to leave the nut attached to the hub, and remove the UJ and hub bolts and leave the shaft and the hub connected as one unit, and only split if 100% required. but for general suspension, brake and UJ work you can leave the nut connected.
Also I find it easier to leave the nut attached to the hub, and remove the UJ and hub bolts and leave the shaft and the hub connected as one unit, and only split if 100% required. but for general suspension, brake and UJ work you can leave the nut connected.
I know that I am resurrecting an old thread but this thread has been an enormous help to me.
My wife was following me in my Wedge & commented that the left rear wheel had a significant “Lean in”.
I checked the rear camber by putting a spirit level vertically against the wheel & it sure did lean in.
I found that a previous owner had stripped the thread in the rear axle locknut & the only thing truly holding the hub & wheel on the car was a split pin after the stripped rear axle lock nut!
The thread was damaged enough that I could not identify for certain if it was a M22 x 1.25 , a 7/8 UNEF or even a M22 x 1.5 thread.
Thanks to this thread, I sourced a 7/8 x 20 UNEF die & 2 industrial quality 7/8 UNEF wide nuts from McMaster-Carr, an industrial supply house here on the US East Coast.
The die cleaned up the thread nicely & the nuts are Red Loctited + split pinned on with 200 ft-lbs of torque.
My wife was following me in my Wedge & commented that the left rear wheel had a significant “Lean in”.
I checked the rear camber by putting a spirit level vertically against the wheel & it sure did lean in.
I found that a previous owner had stripped the thread in the rear axle locknut & the only thing truly holding the hub & wheel on the car was a split pin after the stripped rear axle lock nut!
The thread was damaged enough that I could not identify for certain if it was a M22 x 1.25 , a 7/8 UNEF or even a M22 x 1.5 thread.
Thanks to this thread, I sourced a 7/8 x 20 UNEF die & 2 industrial quality 7/8 UNEF wide nuts from McMaster-Carr, an industrial supply house here on the US East Coast.
The die cleaned up the thread nicely & the nuts are Red Loctited + split pinned on with 200 ft-lbs of torque.
OldRedbarn said:
I know that I am resurrecting an old thread but this thread has been an enormous help to me.
My wife was following me in my Wedge & commented that the left rear wheel had a significant “Lean in”.
I checked the rear camber by putting a spirit level vertically against the wheel & it sure did lean in.
I found that a previous owner had stripped the thread in the rear axle locknut & the only thing truly holding the hub & wheel on the car was a split pin after the stripped rear axle lock nut!
The thread was damaged enough that I could not identify for certain if it was a M22 x 1.25 , a 7/8 UNEF or even a M22 x 1.5 thread.
Thanks to this thread, I sourced a 7/8 x 20 UNEF die & 2 industrial quality 7/8 UNEF wide nuts from McMaster-Carr, an industrial supply house here on the US East Coast.
The die cleaned up the thread nicely & the nuts are Red Loctited + split pinned on with 200 ft-lbs of torque.
Good to hear you got it sorted. New nuts were occasionally available via Parts for TVRs, now Motaclan. I bought half a dozen a few years ago, for spares for the future. Just in case.....My wife was following me in my Wedge & commented that the left rear wheel had a significant “Lean in”.
I checked the rear camber by putting a spirit level vertically against the wheel & it sure did lean in.
I found that a previous owner had stripped the thread in the rear axle locknut & the only thing truly holding the hub & wheel on the car was a split pin after the stripped rear axle lock nut!
The thread was damaged enough that I could not identify for certain if it was a M22 x 1.25 , a 7/8 UNEF or even a M22 x 1.5 thread.
Thanks to this thread, I sourced a 7/8 x 20 UNEF die & 2 industrial quality 7/8 UNEF wide nuts from McMaster-Carr, an industrial supply house here on the US East Coast.
The die cleaned up the thread nicely & the nuts are Red Loctited + split pinned on with 200 ft-lbs of torque.
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