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D type 1933-39

One quick question is the inner distance piece (item P page E5-3 of the Doug Woodrow manual) fitted on the pinion shaft a standard length or is it paired to the pinion, if it is a standard length what should it be?

Re: D type 1933-39

I stand to be corrected but I've never seen one that was matched to the pinion. Just measured one and it is 5/8" wide. However, I also have what appears to be another one (Part No. 1A7675) that is 1 1/8" long but with a larger diameter at one end compared to the other. I think this is for the later (1935 - 38) pinion that is stepped and has a roller bearing adjacent to the pinion gear. Interested to hear if that's correct.

Steve

Edited to add: I think I've just answered my own question in that studying the various parts lists on the Association web site, the distance piece seems constant - part no. 1A7242 - and is shown as a simple, plain unit without larger and smaller diameters. So, what is 1A7675? Can't see it in any of the parts lists but, of course, that doesn't mean it isn't there.

Location: North Yorkshire

Re: D type 1933-39

Thanks Steve

My original one measured up a little bit larger than 5/8 with signs of wear and without any shims in the torque tube the wear marks on the crown wheel indicated that pinion needs to go further into mesh.

Re: D type 1933-39

5/8" sounds too short, I will need to check but from memory I think they should be 3/4", I have found that they are often loose and worn in axles I have rebuilt, if they are too short no amount of fiddling will get the CWP mesh correct, I often made new distance pieces.

Location: Auckland NZ

Re: D type 1933-39

Thanks Ian, 3/4 would of been too large for my axel, sounds like they need to by paired to the pinion.

Re: D type 1933-39

I've now had a hunt around and found another three of these spacers. I've also pulled the torque tube from a complete 1934 D Type axle. All 4 spacers measure 5/8" exactly. Coupled with the one I measured yesterday, that's a total of 5 that are of identical dimensions. Given its history, the 1934 axle has, probably, never been apart since it left Longbridge and the securing nut and spacer are as tight now as they would have been then.

Of course, that could all just be a coincidence.

Steve

Location: North Yorkshire

Re: D type 1933-39


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

Location: Staffordshire

Re: D type 1933-39

Thanks Steve

Re: D type 1933-39

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

Re: D type 1933-39

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

Re: D type 1933-39

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.

Re: D type 1933-39

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

Re: D type 1933-39

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.

Re: D type 1933-39

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

Re: D type 1933-39

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.