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08-06-2018, 06:38 AM
(This post was last modified: 08-06-2018, 06:49 AM by David.H.)
(05-06-2018, 10:31 AM)Ian Williams Wrote: Dufor appear to have made made some rather poor quality parts, I believe they were responsible for the glass king pins which caused a few problems in the 70's and 80's. We also shorten LWB half shafts to make SWB items, some may not know that it is possible to shorten early Big Seven ones to make new LWB.
I think any outfit called DUFOR has to be suspect. In our family when buying Christmas presents some end up as "DUFORs" i.e That one is a "Do For" present......
(04-06-2018, 11:42 AM)Terrytuned Wrote: David for fitting lip seals see BA7C technical website for latest updates under axles oil leaks.
Thanks for that info.
Current problem is to extract the cotter pins from the rear spring / shock absorber pin as I have to replace one because the end is broken off at half way along the thread! I don't imagine there is anything special about the nuts, simply using the second nut as a lock nut?
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Car type: 1928 tourer (mag type), short chassis Gould Ulster
(05-06-2018, 02:58 PM)JonE Wrote: is anyone supplying new rear hubs, Robert?
I have been away at the Chanteloup hillclimb so I am a bit late replying. I believe new hubs are available from A7 Components, but I have not checked.
Robert
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08-06-2018, 11:16 PM
(This post was last modified: 08-06-2018, 11:18 PM by Tony Press.)
(07-06-2018, 10:34 PM)David Cochrane Wrote: (05-06-2018, 02:58 PM)JonE Wrote: is anyone supplying new rear hubs, Robert?
???
BO45 here.
A word to the wise- always check the list of Austin Seven spare part suppliers on the Friends web page 
Cheers, Tony
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(21-04-2018, 02:03 PM)Alan Wrote: 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.
I know there are two threads running.. but this statement deserves clarification for those like me who have never taken such things apart yet! Why exactly are they not interchangeable? What are the characteristics that are different that prevent fit with other connecting parts Is it different teeth, or does it affect the taper joint?
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Why Austin decided to increase the diameter of the journal by 1/64" has never been explained (like that master spline on the clutch). The tapers and the teeth are identical and interchangeable. You can ream out an earlier differential bush to take the thicker halfshaft, or fit a new bush (0.875") to use a thinner halfshaft.
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That's really helpful. So actually, the messing around isn't that great when considering the magnitude of the job anyway?
I note looking in your parts list David that this diff bush - new - is only available at the 0.875, and yet the latest swb (type 3) axle was said to be the strongest. Does that mean there (a) weren't many of the larger spec originally, and (b) people in general don't upgrade to the larger journal.. or just that most people doing this sort of job have the abilty to ream?!
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(14-06-2018, 09:06 AM)JonE Wrote: (21-04-2018, 02:03 PM)Alan Wrote: 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.
I know there are two threads running.. but this statement deserves clarification for those like me who have never taken such things apart yet! Why exactly are they not interchangeable? What are the characteristics that are different that prevent fit with other connecting parts Is it different teeth, or does it affect the taper joint?
Because the increased axle diameter is at the point that the axle runs through the plain bearing on either side of the crown wheel carrier in the differential, if you purchase a later 'large' axle and try to fit it to an early carrier fitted with the 'small' bush it won't go.
Reaming the two bushes true in line is difficult without using a reamer with a guide (which I assume the factory used).
Cheers, Tony.
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(14-06-2018, 09:16 AM)David Cochrane Wrote: Why Austin decided to increase the diameter of the journal by 1/64" has never been explained (like that master spline on the clutch). The tapers and the teeth are identical and interchangeable. You can ream out an earlier differential bush to take the thicker halfshaft, or fit a new bush (0.875") to use a thinner halfshaft.
I have noted that on the thick shaft I have which is finished thin at the taper end, the keyway is very close to the end of the taper and has initiated a crack. If the thin axles were finished the same way and the key cannot be moved further out it may have prompted the alteration. I have enquired on several occasions what the typical measurement for a thin shaft was from edge of original taper to the keyway but no replies. I dont suppose anyone has an original unlapped Austin axle!
If shafts were failing in simple bending as Stuarts even 1/64 extra dia would assist
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14-08-2018, 09:07 AM
(This post was last modified: 18-08-2018, 02:00 PM by Chris KC.)
Having just stripped my 'spare' '31 axle I re-read this thread with interest; not least because it has one short and one 'long' half shaft!
The shafts are both 0.890 type (edit: whoops! no they're not) but nonetheless seem very loose in the bushes either side of the diff. Can anyone suggest what is an acceptable running clearance here?
I guess the fix is to replace the bushes and ream to fit. As Tony mentioned above this is probably better done 'in line' with a guided reamer, is anyone able to point me to a suitable tool for the job please?
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(14-06-2018, 09:16 AM)David Cochrane Wrote: Why Austin decided to increase the diameter of the journal by 1/64" has never been explained (like that master spline on the clutch). The tapers and the teeth are identical and interchangeable. You can ream out an earlier differential bush to take the thicker halfshaft, or fit a new bush (0.875") to use a thinner halfshaft.
There was a note in the Austin Service Journal Jan - Feb 1931 stating "The alteration to the differential shaft is to facilitate manufacture".
I'm not daft enough to assert this as definitive fact, but looking at a sample of 2 shafts, one has diameter 0.875 at the bushing and is rough turned for the rest of its entire length down to 0.865. Naturally the outer portion of the shaft has to be smaller than the inner or it wouldn't pass through the bush. We'll never know I guess whether the shaft started as a single diameter along its whole length but this is suggested. The rough turning op would have consumed a lot of machine time not to mention weakening the shaft.
By comparison the other (LWB) shaft with diameter 0.890 at the bush is unmachined beyond the bush area and has a minor diameter of 0.875.
My guess would be Austin changed the tool to provide a raised (or more raised) section on which to grind while leaving the rest of the shaft clear of the bush and without need for finish machining. If so this would have saved buckets of money.
And yes, both these shafts came out of the same axle!
By the way David, do your 0.875" bushes have enough meat on them to ream out to 0.890" and repair a worn later type axle?
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