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Differential Wear - Graham Barker - 13-04-2024
My 1937 Ruby differential has about 5 degrees of back lash measured by rotating the flange at the input to the torque tube. The differential is a bit growly under load and quieter when load comes off.
Can any useful improvement be made using the adjusters at the back of the differential housing to compensate for crown and pinion wear. I have read Woodrow and some forum threads and articles, but have trouble deciding whether this adjustment is going to be of benefit in this case or will it cause damage. I realise that wear in other components will also be contributing to the backlash. Do people know if the crown and pinion wear is the main cause of backlash? Is this amount of wear serious warranting a complete overhaul? The car appears to have only done 90,000 miles in its life so far and from now on will only be used for occasional outings and club runs, probably only doing 500-600 miles per year.
I would appreciate advice from members on this.
Regards
Graham Barker
RE: Differential Wear - Chris KC - 13-04-2024
Graham, that's quite a big question to answer off the cuff.
I'm ready to be shot down here, but I suggest backlash goes hand in hand with worn gears.
You can try adjusting it a little, but might then find that the diff goes 'rough' or has tight spots - to be avoided at all costs; so then back the adjustment off again until the diff spins nice and freely.
About 40 years ago I (rather rashly) decided to overhaul my back axle a few weeks before a European tour.
I ended up spending an afternoon with Paul Relph in his workshop, and that was the conclusion we arrived at.
I can only say the axle is still running OK - with a fair bit of backlash.
Noise is another matter. If it seems severe or has changed deeper investigation may be warranted.
Even seasoned Austineers baulk at a diff rebuild, and with good reason - so I urge you to seek advice whenever you are unsure.
RE: Differential Wear - Charles P - 13-04-2024
(13-04-2024, 05:51 AM)Graham Barker Wrote: My 1937 Ruby differential has about 5 degrees of back lash measured by rotating the flange at the input to the torque tube. The differential is a bit growly under load and quieter when load comes off.
Can any useful improvement be made using the adjusters at the back of the differential housing to compensate for crown and pinion wear. I have read Woodrow and some forum threads and articles, but have trouble deciding whether this adjustment is going to be of benefit in this case or will it cause damage. I realise that wear in other components will also be contributing to the backlash. Do people know if the crown and pinion wear is the main cause of backlash? Is this amount of wear serious warranting a complete overhaul? The car appears to have only done 90,000 miles in its life so far and from now on will only be used for occasional outings and club runs, probably only doing 500-600 miles per year.
I would appreciate advice from members on this.
Regards
Graham Barker
Are you putting some drag directly on the crown wheel when you make that measurement? I usually stick a finger in through the drain hole to provide some resistance.
RE: Differential Wear - Graham Barker - 13-04-2024
Charles makes a good point. I haven't done anything to lock the crown wheel while testing the backlash. Locking the crown wheel would give me an idea of the amount of backlash that is attributable to the wear between the pinion and crown wheel. I will do that at the next opportunity.
RE: Differential Wear - Tony Press - 14-04-2024
The backlash is often the fore and aft movement of the pinion shaft- check and adjust the end float with the adjuster behind the top flange.
My three early differential pinions all had this end float.
Tony.
RE: Differential Wear - Graham Barker - 14-04-2024
I have now drained the diff and was surprised by the amount of metal in the oil considering that it has only done about 900 miles since I changed the diff oil. The oil drained on the previous oil change had a lot of particulate too, but I didn't know how long that had been running. The photo of the oil in the dish shows sludgey mixture that initially came out of the drain and the more liquid oil followed it. The sludgey mixture contains bronze and silver particles, whereas the more liquid oil only has fine bronze particles.
The oil patches on the cloth in the other photo from left to right are new oil, sample from the more liquid oil, sample from the sludge.
I checked the backlash with my finger on the crown wheel and find that very little of the movement is between the crown wheel and pinion. Most of the movement is further back in the diff or the axles.
Does this help revered experienced forum members to further suggest or confirm my problem and it's seriousness.
Regards
Graham
RE: Differential Wear - Tony Press - 14-04-2024
You won't get backlash between the crown and pinion if the problem is end float in the pinion shaft- the pinion winds up and down as you rotate the top flange.
RE: Differential Wear - Ian Williams - 14-04-2024
What oil did you put in that axle Graham? As others have said its a likely a far wider issue that simply adjustment, I would go so far as to suggest suggest that you have an impending failure on the horizon. Personally I would remove the axle and strip it down for inspection. You might get lucky and after replacing one or two bearings be able to set it up well enough reduce risk of a future catastrophic failure, otherwise unfortunately axle rebuilds are rather costly. I am currently in the process of moving back up to Auckland so if you get it apart I could be available and willing to offer some help and advice. I am not however in a position to do a full rebuild for you at present so you will need to be confident and equipped enough to do the work. Graham O has my number should you wish to discuss.
RE: Differential Wear - Charles P - 14-04-2024
(14-04-2024, 08:26 AM)Ian Williams Wrote: What oil did you put in that axle Graham? As others have said its a likely a far wider issue that simply adjustment, I would go so far as to suggest suggest that you have an impending failure on the horizon. Personally I would remove the axle and strip it down for inspection. You might get lucky and after replacing one or two bearings be able to set it up well enough reduce risk of a future catastrophic failure, otherwise unfortunately axle rebuilds are rather costly. I am currently in the process of moving back up to Auckland so if you get it apart I could be available and willing to offer some help and advice. I am not however in a position to do a full rebuild for you at present so you will need to be confident and equipped enough to do the work. Graham O has my number should you wish to discuss.
Do as Ian says.
It’s usually the best option.
RE: Differential Wear - Graham Barker - 14-04-2024
Hi Ian,
Thanks for the offer of help. I won't be doing anything for a month or more. Will contact you through Graham O.
Regards
Graham