Half Shaft replacement AG tourer 1932

[David.H]

It is a long time since I changed a broken half shaft....found a new one in a Garage in Farnborough opposite the RAE  up in their rafters. It cost about 20/6d as far as I recall in 1957 with it's original packing & price tag!! I bet it costs a bit more now.
Well I need to  do it again (different car, same problem). The o/s hub is distinctly loose & appears unconnected to anything!
I will have to make/borrow a half shaft/brakedrum tool, I have a stout 3/4BSW spanner, so I should be able to get it apart, but I cannot remember if the shaft bits will simply pull out of the diff, or do I have to split the diff?
I am not looking forward to seeing the state of the hub taper etc. I will know the half shaft length when I get it apart
I am not sure of the axle type (three I think), It has stamped on the diff "49541 and then what looks like a 9 above
the 1...the numberer ran out of space!) Any code-brakers with ideas?
The axle measures about 36" between backplates (Morris Minor ones for the hydraulic brakes )

[JonE]

I bought one of these (below) and you need a 3/4 Whitworth socket to tighten up tight after all done.
Both Ruairidh and Chris Gould advised me that one does need to split the diff to replace the shaft, and make sure the exact position is maintained. I just did the key on mine.

https://www.carandclassic.co.uk/car/C918694

Are you sure its not 9 over 44 at the end? Sounds like SWB from that date anyway?

Some of advice given to me - I copy directly from Chris's email...
Unfortunately to do the job properly you will have to remove the half shaft. You don't have to remove the whole axle, just the nearside half. Support the car on axle stands under the rear cross member. Remove the offside hub flange. Remove the near side spring pin and jack up the differential case until the nearside casing clears the spring. Undo the casing bolts and remove the half casing complete with differential and half shafts. Dismantle the differential and remove the half shaft. The two sides of the differential cage must go back in the same position relative to each other. You will find that there are marks on the side of it to line them up.

Check that the taper isn't too damaged. The hub flange must be lapped onto the half shaft to give a matt finish all round. Use course grinding past at first followed by fine. You can buy the paste from motor factor. Halfords would probably sell it. The tins often have lids on both ends, with coarse paste in one end and fine in the other. There is a danger that if it is overdone The gear on the end will move outwards too much and bind on the inside of the differential. I have in emergency got over this problem by wrapping the taper with a piece of shim brass. Use a new key which must be a tight fit in the groove. Make sure that there is clearance on top of the key when the hub flange is fitted. Clean off the grinding paste thoroughly, reassemble and make sure that the half shaft nut is very tight. Use a tight fitting split pin. Make sure that the castellation lines up with the hole in the shaft. If it doesn't, file the face of the nut so that it will wind on until it does.

Lots of good pages on web too, from Dorset and Devon clubs, on halfshafts....

[David.H]

I bought one of these (below) and you need a 3/4 Whitworth socket to tighten up tight after all done.
Both Ruairidh and Chris Gould advised me that one does need to split the diff to replace the shaft, and make sure the exact position is maintained. I just did the key on mine.

https://www.carandclassic.co.uk/car/C918694

Are you sure its not 9 over 44 at the end? Sounds like SWB from that date anyway?

Some of advice given to me - I copy directly from Chris's email...
Unfortunately to do the job properly you will have to remove the half shaft. You don't have to remove the whole axle, just the nearside half. Support the car on axle stands under the rear cross member. Remove the offside hub flange. Remove the near side spring pin and jack up the differential case until the nearside casing clears the spring. Undo the casing bolts and remove the half casing complete with differential and half shafts. Dismantle the differential and remove the half shaft. The two sides of the differential cage must go back in the same position relative to each other. You will find that there are marks on the side of it to line them up.

Check that the taper isn't too damaged. The hub flange must be lapped onto the half shaft to give a matt finish all round. Use course grinding past at first followed by fine. You can buy the paste from motor factor. Halfords would probably sell it. The tins often have lids on both ends, with coarse paste in one end and fine in the other. There is a danger that if it is overdone The gear on the end will move outwards too much and bind on the inside of the differential. I have in emergency got over this problem by wrapping the taper with a piece of shim brass. Use a new key which must be a tight fit in the groove. Make sure that there is clearance on top of the key when the hub flange is fitted. Clean off the grinding paste thoroughly, reassemble and make sure that the half shaft nut is very tight. Use a tight fitting split pin. Make sure that the castellation lines up with the hole in the shaft. If it doesn't, file the face of the nut so that it will wind on until it does.

Lots of good pages on web too, from Dorset and Devon clubs, on halfshafts....

Hours of harmless fun ahead! The AG is SWB chassis....I will have another look at the numbers.
The instruction " remove the n/s spring pin" reminds me of the instruction to remove the front spring pin on a TR3 rear axle where you insert a 3/8 unf bolt into the tapped hole in the spring pin and "pull it out" As a well known TR man wrote "only an optimist will attempt this method!" Usually you ended up cutting or burning it out! Maybe the A7 is easier. I don't remember all that activity last time. Time obviously dulls the pain.
But thank you for the advice
David

[Bob Culver]

It is important the hub puller is a good fit. If the threads become damaged the process becomes complicated! If someone applies the brakes heavily may hold the hub adequately. On standard sytem can realx the front adjustment.

The religious ritual of wholescale lapping of hubs was questioned in the old website and caused a furore. Yet the original axles and hubs were intact on my well used car at 110,000 miles with no lapping.

The best course of action will depend on the state of the parts. If the failure has followed from the hub having been loose the hub will likely be too damaged to warrant reuse. New are available. As above, prolonged lapping can lead to the axle jamming inside the diff, and the new axle becomes non standard. Investigation with thin engineers blue or somesuch is worthwhile. Provided it does not contact mainly at the small end a new axle and new hub may not benefit from amateur lapping. The taper must make full contact inboard of the keyway. (Not sure if this is practicable on all thin axles) Even if undamaged, it is likely the hub has been extensively lapped in the past.

The  bearing load (and crown wheel mesh) is determined by the thickness of any gasket separating the diff halves. It is prudent to compare the assembled thickness. Any change will require compensating adjustment of the left side. Beware the bearings are not overloaded before any readjustment.

[JonE]

again for completeness in thread, I understand SWB are 22.5" and LWB 23.5" length... but buying new presumably you won't have an issue!

[Alan]

Just remember short wheelbase half shafts come in two diameters. Measured on the polished bit just behind the gear teeth they are either 0.875in or 0.890in. Without a lot of messing around they aren’t interchangeable.

[David.H]

Just remember short wheelbase half shafts come in two diameters. Measured on the polished bit just behind the gear teeth they are either 0.875in or 0.890in. Without a lot of messing around they aren’t interchangeable.

Thanks Alan. I have a used  22.5" with .890 diameter in fine light rusty condition (!) with a rather battered keyway and taper in stock that came with another car. I did not know there were two types! Can it be "cleaned up"? some radial partial grooves are up to .020" deep. I suppose the state of a hub will also be significant.
I don't know yet if my hub is just very loose on the taper or if the shaft is broken, when I get the nut off (it had no split pin (!) so may be easy....)  I may know more.
I don't think the last owner understood much about Sevens! I have found a few half hearted jobs (not particularly difficult ones) that seem to have been started & then abandoned. This may be one of them.
 We will see!

[JonE]

no- one replied to this further... I will bump as I also now have one spare halfshaft with a keyway that isnt competely parallel. (i.e. akin to 'rather battered' above!)
If one if getting an essential spares package together, is it possible to put time into making a bespoke key to fit, so that it is matched for when being used in future? Or can a keyway be built up?

[Stuart Giles]

is it possible to put time into making a bespoke key to fit, so that it is matched for when being used in future? Or can a keyway be built up?

You could fill the keyway with weld and cut (or get cut) a new keyway on the other side of the shaft after remachining the taper.

Recently, I have made all my "short" halfshafts out of knackered "long" Austin factory ones. It is also necessary to fill the keyway with weld when doing this conversion as otherwise some of the original keyway will appear in the screwcut thread of your 'new' short halfshaft..

[Ruairidh Dunford]

When you do change the shaft David, I personally would also fit modern lip seals either side of the diff.