I think you've put that one to bed Steve!

Location: Staffordshire

Thanks Steve

Steve, this is confusing, I have been out and checked several in my workshop as well as my notes 3/4" is the measurement that I have. With a 5/8 bearing spacer fitted there is no way that the pinion would go far enough into mesh with the crownwheel. Am I missing something and are we both talking about the same item???

Location: Auckland NZ

I think we have an answer Ian. I've just had an email from the ever helpful Terry Griffin reminding me that the 11/8"pinion has a narrow roller and 3/4" spacer whereas the 1" pinion has a wider bearing next to the pinion and a 5/8" spacer. So, looks like we were both right!

Steve

Location: North Yorkshire

We must be careful here- Woodrow is incorrect in showing the single picture for a 1933-1939 'two piece' torque tube showing the pinion shaft without step and a roller bearing.

There were two versions on this torque tube assembly, the first from 1933 to 1935 had a parallel 1" pinion shaft fitted with 1" bore ball bearing (RHP MJ1 SKF RMS8) at the pinion end which was 3/4" wide. The spacer (Inner distance piece for pinion bearing) had Part Number BP100.

In 1935 when Longbridge decided the ball bearing was not strong enough they went back to a Roller Bearing at the pinion end (RHP LRJ 1 1/8 SKF CRL9) with 1 1/8" bore requiring a stepped pinion shaft. At 5/8" wide this bearing now required a 1/8" longer spacer BP180 1A7242.

Hence there are two spacers - 5/8" from 1933 to 1935, 3/4" from 1935 to 1939.

Sorry for the long explanation but please put this in your Woodrow to avoid further confusion- differentials are hard enough to re-build at the best of times, especially with the special pair of angular contact bearings which is another story.

Tony.

Location: Malvern, Melbourne, Victoria, Australia.

The history of cars now hard to establish. An RP diff never apart must have led a quiet life. On my car the ball pinion was replaced at 40,000, and again later, altho the original cwp and axles were still intact at 110,000.

Of the few diffs I have had apart evidence of the spacer wearing on most of. As there is little preload on the thrust bearings, and one is laterally free in housing, seems unlikeley races would resist turning even if debris in them.

Perhaps the nut is one place where a torque figure might be helpful.

Location: Auckland, NZ

I am sorry but that posting doesn't seem to add anything very much to the discussion about the spacer length

Tony.

Location: Malvern, Melbourne, Victoria, Australia.

Hi Tony

If you applied such a test to everything a huge proportion of all postings would fail and the Forum very dull. It does further address the question of why so many not the exact length but worn short. And reinforces that it is an assembly detail warranting careful attention.

My experience with other cars has been that tab washers are quite critical. Must not be of too soft steel, and must be very flat.

Location: Auckland, NZ

If the spacer is short through wear then you have a much greater problem - one or both bearings (which should be a tight fit) are loose on the pinion shaft and no tightening of the shaft nut will cure this.

Tony.

Location: Malvern, Melbourne, Victoria, Australia.