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+--- Thread: Rear Crown and Pinion set up 1934 RP (/showthread.php?tid=9501)
Rear Crown and Pinion set up 1934 RP - John - 31-07-2024
Hi, I've just started to rebuild my back axle on my 1934 RP box saloon and need some advise on adjusting and setting up the crown and pinion properly. I think I have managed to get it aligned but don't have the experience to know I have definitely got it right and I don't want to cause more problems at a later date when the car is running!
I have assembled it and run the drive with a socket on the end of a drill to turn the axle for getting an idea of the contact being made on the crown and pinion, I've used engineers blue on a quarter of the the crown wheel. The results are in the photos attached (this is after several attempts and adjustments). I do have some doubt I have got it right as there were 2 shims in each side of the torque tube from on the original set up, but I have removed one set and it seems to seat better, but the advice I have read is to put all of them back as it was.
Any help on if it looks right or advise on getting it better would be very much appreciated.
Regards
John
Complete set up..jpg (Size: 154.82 KB / Downloads: 264)
Crown marking 1.jpg (Size: 107.26 KB / Downloads: 264)
Crown marking.jpg (Size: 72.52 KB / Downloads: 263)
Pinion markings 1.jpg (Size: 107.59 KB / Downloads: 263)
Pinion markings.jpg (Size: 112.9 KB / Downloads: 263)
RE: Rear Crown and Pinion set up 1934 RP - Chris KC - 31-07-2024
John, let me confirm - are you fitting new (or 'new' used) crown wheel & pinion? Or putting the old parts back in?
RE: Rear Crown and Pinion set up 1934 RP - John - 31-07-2024
Chris,
I am fitting existing old parts back together (sorry, didn't explain that very well!).
John.
RE: Rear Crown and Pinion set up 1934 RP - Robert Foreman - 01-08-2024
John,
If you are using an original Austin cwp then on the end of the pinion will be a number etched in with an electric pencil. Say for example 20 this equates to a 20 thou shim. This would be a good starting point because that was where it was first set at.
RE: Rear Crown and Pinion set up 1934 RP - Chris KC - 01-08-2024
If simply replacing them in an axle which has already been their home, is there any reason to think the existing shims were not OK?
(Although I don't question the wisdom of checking, the fact that it's been running like that for a while suggests it's at least not suicidally incorrect).
Nothing should have changed, except possibly the thickness of the gaskets on the casing, which would influence backlash but not meshing.
RE: Rear Crown and Pinion set up 1934 RP - John - 01-08-2024
Hi both,
thanks for getting back to me, after sleeping on it, it didn't feel right not putting the original amount of shims back in (which are in perfect condition), and you have confirmed my thoughts, so this morning I have installed all the shims and used this link below, I found last night (which was really helpful), to adjust the crown correctly using the adjusters.
https://austinsevenfriends.co.uk/Bruce/Differential_Adjustments.htm
I have attached some more photos of this mornings work and feel much more confident this is correct, as the adjusters seem to be in the original positions, as before I stripped it down I marked one of the serrations through the adjustment holes.
I have done quite a bit of work to the Austin since I saw it in a friends barn rotting away and have learnt a lot along the way over the last few years, using the knowledge and advise you guys and others have given me, but still have a lot to learn before I get it back on the road!
Hopefully you both will confirm the markings on the pinion look better from the photos attached, just need to check the backlash now?
Many thanks.
RE: Rear Crown and Pinion set up 1934 RP - Chris KC - 01-08-2024
John, I would be setting the backlash at least somewhere close before doing the blueing, as it will influence where the teeth contact to some extent. It's important though to realise that with worn gears you will struggle to get perfect adjustment i.e. you might well set 4 thou backlash and find it has all gone tight and feels rough when turned over. In such a case extra backlash is infinitely preferable to 'tight' gears.
RE: Rear Crown and Pinion set up 1934 RP - John - 01-08-2024
Thanks Chris, I think the backlash is somewhere near, but will have a look and will redo if necessary.
Thanks for your help so far!