1930s half shaft.

[Tony Fearn]

There's more to come, but this afternoon I re-assembled the back axle.
I haven't put on the hubs because I'm used to the sort of 'Woodruff' key shown in photo one.
The hub slides on to it, and when all is tight I can put in the split pin through the castle nut.

IMG_0014.JPG

However, the new old stock half-shaft has a different type of keyway after the thread.
I tried it with the same sort of key as you see in the photo above, but it slides around when I try to do-up the hub on the axle end.

IMG_0015.JPG

Is there some other type of key, which I haven't got, or is there a technique using the key as in the top photo?

Tony.

[BarryCambs]

Hi Tony

I think it just had a a longer key, rather than special design. I remember when I used to work in Agricultural Engineering we used to cut them to length when we needed them. The box with the bar stock in was labelled 'Key steel', so you can't just fashion something from what ever is lying around.

If the key you have is the right section, I think you could make a spacer to fit behind it to stop it siding up the shaft while you fit it? It could get you out of trouble.

[Forumadmin]

I bought a selection of key steel off the Internet in imperial sizes.

[Tony Fearn]

I boughtba selection of key steel of the Internet in imperial sizes.

Keith. A very useful selection to have sitting on the shelf.

Barry, thanks for the reply.
I'll explore that in the next few days.

Ian, The bore was 1.125" and the two bearings were £35 in total. (Oops I forgot the VAT). It would have been cheaper but one of them was a sealed type which cost a fraction more.

17a new bearings.JPG

Tony.

[Tony Fearn]

10 balance gear shaft and ends of half shafts showing split collars in their housing.JPG

I’ve spent today sorting out the ending of the half-shaft saga. The photo above shows the internals of the diff when back together. I’ve a feeling that there should be about 5 thousands of an inch clearance between the end of the half-shafts and the balance gear shaft, as that was the clearance of the un-replaced shaft on the right of the photo.

14 inside diff housing showing inner bearing seats.JPG

This photo shows the inside of the aluminium differential ball where the inner bearings fit.

16 Wheel bearing-fitting tools!.JPG

You know the phrase – ‘it’ll be useful one day’, and so they were. I’ve had these box spanners for over 40 years and this is the first time I’ve used them, although they’ll need fettling since being bashed with the lump hammer to ‘ease’ the wheel bearing in place in its housing and around the end of the shaft.

21 Rear brake actuators.JPG

I include this photo of the rear brake actuating system, even though it seems obvious how to refit them. The levers are handed and lean into the centre-line of the car. I also note that the levers hang downwards, not upwards as a fellow pre-war enthusiast had them, and wondered why the brakes weren’t up to scratch. Don’t lose the special washers that go into the groove in the rod otherwise the lever might just go round and round.
And so the saga ends, well it will do when I’ve had the shock absorber arm lug welded back on. It’s part of a casting, so don’t hit it with the lump hammer. Use a piece of hardwood to help to split the casing.

22 Shocker arm lug broken off.JPG

Here’s the axle ready to be cleaned and painted

23 rear axle back together for cleaning and painting.JPG

Now for the confessions of the novice I alluded to at the beginning.
Dismantle, renew shaft and bearings, clean and re-assemble.
Dismantle again because the crown wheel was at the wrong side when viewed through the pinion hole – fastest Jowett in reverse, and re-assemble.
Dismantle for a third time – forgot to put the aluminium packing rings back, and re-assemble.
Now I think it’ll work perfectly.
N.B. Check for and remove burrs and clean everything up before you put it back.

[Tony Fearn]

6 both tubes removed showing inner bearings - Copy.JPG

I can't get my head around why the aluminium packing rings are so important.
Can any of you engineers enlighten me please?
Tony.

[AlanBartlett]

Do they go on the front pinion. Do they not set the depth in which the teeth mesh with each other?

[Tony Fearn]

Hello Alan.
That seems to be the logical place for these rings, but as you can see from the scan of the back axle page from the Pitman book, earlier on in this rather lengthy post, they are found on the outside of the inner bearings.
I replaced them in the bearing housing of the aluminium diff case (after cleaning the housing and the rings with brake cleaner), and put a drop of super-glue on the back to hold them in the housing to facilitate re-assembly.
It was quite surprising how much backlash there was in the pinion without them.
Now they are in place there is minimal backlash.
The quick sketch below might explain their position.

Image (140).jpg

I can't see how they do it, but they certainly do the job of removing backlash.
regards,
Tony.

[StevenGray]

Tony
Put simply the distance over the bearings is less than the distance between the bearing recesses in the axle housings when asssembled, the shims then take up the difference, I would expect that originally, different thickness shims were available to get the correct backlash setting for the pinion, so without them the differential would move from side to side. I would suggest that the diff would be dry fitted to set up the pinion backlash then dismantled and the half shafts fitted. As the wheel end bearings are not locked in place they only carry the vertical load, the end thrust from cornering is taken by the inner bearings. Reference is made in the text of the Pitman book page to the fitment of the shims.

Steven

[Tony Fearn]

Hello again Steven,
It's some time since we corresponded via JowettTalk, and we're all glad to hear from you and for your input.
I now fully understand why the spacer rings are important, as will anyone else reading this post in the future.
It's wonderful when you know why something is done, and can understand the reasoning.
I'm always surprised as to just how many Jowett Car Club members have a background in engineering.
No wonder many of these are potty about trains, or even buses.
My background is Pathology, far removed from engineering, hence my lack of depth of engineering knowledge.
I just treat the pre-wars as large Meccano sets.
Wishing you all the best,
Tony.