Pinion diff bearing #18

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bloodysalmon
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Pinion diff bearing #18

Post by bloodysalmon » Mon Oct 21, 2019 5:32 am

Does anyone have any of these pinion bearings #18 for sale?
If not do you know where to get some, the named reference number or stamped model of them?
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Tc diff.jpg
Chris Blood
TC1472,TC2686,TC4245,D-type D0407

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Marv
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Re: Pinion diff bearing #18

Post by Marv » Mon Oct 21, 2019 6:25 am

Have you tried Moss Europe, it's Moss #125-000 listed at $72.00 also used in the midget, Sprite and Austin Healey alternators. Should be in stock but if not, I'm sure Doug at FTFU has them and he ships across the puddle..

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bloodysalmon
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Re: Pinion diff bearing #18

Post by bloodysalmon » Mon Oct 21, 2019 8:14 am

Cheers for this Marv; yes, Moss Europe has them at £54.40
However, they charge a premium so perhaps I can find others (as i need 3, yes for 3 diffs) elsewhere if I can establish the dimensions! Does anyone therefore able to confirm whether these at Moss are 62x25x17mm?
Chris Blood
TC1472,TC2686,TC4245,D-type D0407

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Steve Simmons
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Re: Pinion diff bearing #18

Post by Steve Simmons » Mon Oct 21, 2019 8:14 am

Try Roger Furneaux in the UK. He sells a tapered bearing kit that is superior to the original.
1949 TC8975 / XPAG 9609
1949 TC9849 EXU / XPAG 10507
http://www.mgnuts.com

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bloodysalmon
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Re: Pinion diff bearing #18

Post by bloodysalmon » Mon Oct 21, 2019 8:47 am

Yes Steve, I thought he did his own ... I have sent him a msg about his RA021 bearings; however it looks like you have to do machining work too along with shims etc, is this correct?
Chris Blood
TC1472,TC2686,TC4245,D-type D0407

Bill Davis
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Re: Pinion diff bearing #18

Post by Bill Davis » Mon Oct 21, 2019 8:59 am

Hello Chris,

I used tapered bearings (sourced locally) for the pinion shaft on the last 2 diffs I rebuild. Some shimming is required with tapered bearings but no machining necessary when using the thick shims.

See Roger Furneaux’s manual here; https://fromtheframeup.com/uploads/TT_C ... Set_Up.pdf Roger can supply the proper shims as well as the tapered bearings or (I believe) supply the Original bearings if you want to go that route.

I also found this in my Diff Files:

Tapered Roller Bearings for Diff
Bob Grunau date: 18.05.1998
subject: Re: MG TC Crown and Pinion

All bearings numbers are FAG or Timken Tapered Roller bearings:
Pinion front - 62 mm x25 mm x25.25mm thick- #32305
Pinion rear - 62mm x 25mm x 18.25 mm thick- #30305
Carrier , 72mm x35mm x 18.25 mm thick- #30207 ( 2 required ).
Replacement of the carrier bearings is straight forward, just install the
tapered rollers and set up the pre-load and clearance by the book.
The pinion bearings are a bit more involved. First because the rear tapered
roller is 18.25mm thick, where the original flat roller was 17mm thick,
therefore you need to move the pinion bearing carrier housing FORWARD
1.25mm, or machine a 1.25mm deeper groove in the housing so the new tapered
roller bearing seats 1.25mm further forward. The key thing is to keep the
rear of the rear bearing, and therefore the pinion head, in the same
location relative to the crown wheel. I used an additional 0.050" shim
under the pinion carrier and then made fine adjustments of the pinion
location.
Second, you need to preload the pinion bearings by changing the length of
the spacer between the bearings. The Y book calls for 5 to 6 inch pounds
pre-load on the bearings when the flange nut is tight. The TD pre-load is
11 to 13 inch pounds or 1 foot-pound preload.
I used the Y recommended preload of 5 to 6 inch pounds.
I would recommend getting a reference measurement of the pinion location
BEFORE disturbing the original bearings. Then, you can set the pinion in
the same location using the tapered rollers.
This is not a 5 minute job, but if done correctly should end up with a much
stronger gear set.
Bob

Hope some of this will be of use.
Regards, Bill Davis

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Duncan M
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Re: Pinion diff bearing #18

Post by Duncan M » Mon Oct 21, 2019 9:15 am

Chris, you will find that the #18 original bearing can be replaced with a 5305. 62 x 25 x 25.4 (1"). I used a SFK5305A along with the original undamaged scroll seal cap (#20). The bearing is/was a double row angular contact bearing.

The other (roller) pinion bearing #15 can be replaced with the SKF Explorer NU305 ECM bearing.

Be sure and check that your scroll "seal" on the cap has not been damaged. If it is damaged, you will need to go with the perishable modern rubber type seal, as nobody seems to offer the original (all steel) type scroll seal cap (#20) any more.
oilscroll (3).jpg
oilscroll (3).jpg (73.96 KiB) Viewed 703 times

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bloodysalmon
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Re: Pinion diff bearing #18

Post by bloodysalmon » Mon Oct 21, 2019 11:29 am

... ok this is all good stuff gents.

Duncan, what would you therefore suggest as an appropriate rubber seal too then?
Chris Blood
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Ray White
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Re: Pinion diff bearing #18

Post by Ray White » Mon Oct 21, 2019 12:54 pm

Hi Chris. My double row ball bearing literally fell apart on the bench.! Roger F says this is normal!

I am currently replacing the C.W.P with a 39/8 which gives a slightly higher gearing of 4.875 : 1 - the same as the TA.

You can see the result of the bearing failure on the pinion gear so to ensure there is no repeat I shall be fitting taper roller bearings. Roger F has supplied a kit. I just have to get on and fit it. :eek:


Image

P.S. I would like to see your cars and have a chat if you would like to forward your address.

Cheers, Ray.

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Duncan M
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Re: Pinion diff bearing #18

Post by Duncan M » Mon Oct 21, 2019 2:06 pm

Chris-
My reverse scroll on the original cap had no damage, so I simply put it back in service. It does not leak.

My pic above shows what the undamaged "seal" looks like. Checking and replacement of the carrier bearings is routine maintenance on a gearset like this. It can be done with the diff in the car. Those original double row R&M bearings had BRASS cages that would disintegrate over time from the acids created in dirty old gear oil that never got changed..

SteveW
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Re: Pinion diff bearing #18

Post by SteveW » Tue Oct 22, 2019 12:29 am

Hi Chris,

There is a place in Ilkeston that sells bearings. I took my original wheel bearings in and they found a direct replacement for lower cost that the MG suppliers who charge a premium. I forget what it's called, but I know where it is.

By the way, I should have some time next week if you want to get together to have a look at your lights.

Steve

cdrolshagen
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Re: Pinion diff bearing #18

Post by cdrolshagen » Tue Oct 22, 2019 2:24 am

Hi Chris,
# 18 is a 4 point ball bearing,
Simpley Bearing have these in stock,
https://simplybearings.co.uk/shop/Beari ... index.html
Carl

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Duncan M
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Re: Pinion diff bearing #18

Post by Duncan M » Tue Oct 22, 2019 12:17 pm

Not sure where the incorrect size of 62 x 25 x 17 is coming from. #18 is a double row angular contact bearing of dimensions 62mm x 25mm x 1" (25.4mm).

Here is a couple pics of the known original R&M bearing. It had a single piece inner 2X race, and split outer race.
R&M1.jpg
R&M1.jpg (30.47 KiB) Viewed 640 times
R&M2.jpg
R&M2.jpg (378.98 KiB) Viewed 640 times

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bloodysalmon
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Re: Pinion diff bearing #18

Post by bloodysalmon » Mon Oct 28, 2019 9:56 am

from the information Bill has provided I have now managed to acquire all the correct replacement roller bearings for all my diffs. Thank you
Chris Blood
TC1472,TC2686,TC4245,D-type D0407

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