Gearbox woes

Discuss mechanical problems here.
ndevans
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Re: Gearbox woes

Postby ndevans » Wed Apr 17, 2019 9:49 am

Thanks.
How long is the distance piece?

Cheers N
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'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Wed Apr 17, 2019 12:47 pm

I cannot give you an exact measurement but if you are going to make one - just shorten the spacer until the roller bearing is clear of the layshaft thrust face or clear of the outer circlip groove when the spacer is resting against the inner circlip.


ndevans
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Re: Gearbox woes

Postby ndevans » Wed Apr 17, 2019 10:09 pm

Think I've found the distance piece. It was wedged inside the laygear. I think the inner circlip is missing. Is that the distance piece in the bottom left of the photo?
Cheers N
IMG_20190417_215432~2.jpg
IMG_20190417_215432~2.jpg (1.44 MiB) Viewed 833 times
cheers N
'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Thu Apr 18, 2019 8:04 am

Well done.

That is the spacer.

There is in total four circlips holding the roller bearings and spacer in place. See the BMC wksp man gearbox exploded drawing for position details.


ndevans
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Re: Gearbox woes

Postby ndevans » Sat Apr 27, 2019 10:43 pm

Ok, reassembly is starting now. Checking the laygear endfloat, I have the largest washer available, 0.131", and still have more than 0.003" play. I haven't renewed the front washer or the laygear, just the rear washer.
I can get a 0.004" feeler gauge in there. Not tried anything larger, but I reckon the endfloat is likely to be 0.005-0.006".
How critical is this? What can I do about it?

Cheers N
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'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Sun Apr 28, 2019 8:10 am

0.005" - 0.006" end float of the layshaft is within acceptable limits.

It is not critical that you have less (end float should not be less than 0.004") but you should aim for no more than 0.006".

You could replace the front thrust washer and see if it make any difference.


ndevans
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Re: Gearbox woes

Postby ndevans » Sun Apr 28, 2019 8:44 am

I thought the endfloat was 0.003"? The Haynes manual says 0.003".

Cheers Neil
cheers N
'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Sun Apr 28, 2019 9:15 am

Whilst the Haynes manual may say 0.003", 0.004" is acceptable and you would be hard pushed to tell the 0.001" difference especially with a feeler gauge.

What you have quoted is within acceptable limits. You can try and reduce it down to 0.003" if you so wish but it may take a lot of effort to do so.

The rear thrust washers available from MOSS are Pt No: 2A3025....0.125"/0,126" and Pt No: 2A3024....0.123"/0.124.

The quoted thickness of your existing thrust washer @ 0.131" is larger than what is available - so unfortunately it appears you are stuck with what you have.

Moss do not quote a thickness for the front thrust washer Pt No: 2A3023, neither do ESM.

ESM quote the same part numbers and thickness for the rear thrust washer.

Only the two thicknesses of rear thrust washer appear to be available.

You have to take into account that there may also be some wear to the gearbox casing thrust washer faces as well as wear of the thrust washers themselves.


ndevans
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Re: Gearbox woes

Postby ndevans » Sun Apr 28, 2019 3:28 pm

Ok thanks, I'll go ahead and rebuild.
Moss do 3 or 4 sizes of rear thrust washer. I have a 2A3027, which is 0.131", I got from Moss Bristol. It's in the catalogue, but maybe not online.

Cheers N
cheers N
'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Sun Apr 28, 2019 3:43 pm

Having quoted the part number 2A3027 it appears on the MOSS on line spare parts list - also on the ESM on line parts list.

It is marvelous what a part number will do. :wink:

No matter - you have the thickest thrust washer so you are still stuck with the end float you have.

You will experience no problems with the lay gear even if the end float is 0.006".

Phil


ndevans
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Re: Gearbox woes

Postby ndevans » Sun Apr 28, 2019 9:42 pm

Thanks Phil for the reply.

In fact, I've just found that ESM sell a 0.132-0.133 washer as well, so I might try that.

Ok, 2 more questions. First-do I replace the 1st gear? As you can hopefully see in the photo, a couple of the teeth are pretty rough, with sharp edges where pieces have broken off. Do I replace? Seems sensible to me, as it's in bits at the moment.
IMG_20190428_182757~2.jpg
IMG_20190428_182757~2.jpg (804.27 KiB) Viewed 666 times
2nd-guess who managed to lose the sync springs and balls when he took the 1st gear and 2nd gear sync ring off?
I've got new springs and balls, but how do I get them back in under the 1st gear? There are 3 of them located at 120deg intervals on the sync ring. Any tips would be appreciated!
IMG_20190428_182843~2.jpg
IMG_20190428_182843~2.jpg (446.39 KiB) Viewed 666 times
Thanks,
Neil
cheers N
'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Mon Apr 29, 2019 7:23 am

Well done for finding thrust washer Pt No: 10G159X (oversize) 0.132" - 0.133".

The above does not appear to be listed on the MOSS web site or in the BMC factory parts list so it may be produced especially for ESM.

I would replace the gear whilst you have the gearbox in pieces.

As regards the synchro hub - without the BMC special tool you could try something like a small piston ring clamp.

Do the job inside a plastic bag so if it fly's apart again the springs and ball will be caught.
Last edited by philthehill on Mon Apr 29, 2019 8:50 am, edited 1 time in total.


ianmack
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Re: Gearbox woes

Postby ianmack » Mon Apr 29, 2019 7:43 am

I certainly wouldn’t use that first gear again, those teeth are disintegrating. I had a tooth come off a motorcycle gearbox a while ago and the gearbox seized completely, always an unpleasant experience especially on a bike.

I have some spare gears and might have one.

oliver90owner
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Re: Gearbox woes

Postby oliver90owner » Mon Apr 29, 2019 11:42 am

[quote=philthehill post_id=637774 time=1556518988 user_id=17277

As regards the synchro hub - without the BMC special tool you could try something like a small piston ring clamp.

Do the job inside a plastic bag so if it fly's apart again the springs and ball will be caught.
[/quote]

Phil,

A good suggestion - doing it inside a plastic bag. I have used that technique for a range of jobs ( eg recovering the queen bee from a cage with other worker bees present).

I would initially be cutting a tapered shaft, to fit the ring, as a first stab. Milling grooves, at 120 degrees, on the taper might help, if necessary. Is that like the special BMC tool? A piece of dowel for the woodworkers would suffice just as well?

RAB

ndevans
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Re: Gearbox woes

Postby ndevans » Mon Apr 29, 2019 1:37 pm

Minisport actually sell a tool for fitting sync springs and balls, but I'm not sure it'll work on the Minor, and I'm loathe to shell out £30 then find it's no good.
cheers N
'69 Traveller, 1275, discs.

oliver90owner
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Re: Gearbox woes

Postby oliver90owner » Mon Apr 29, 2019 5:36 pm

Ask them? They are only a phone call, or email, away!

philthehill
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Re: Gearbox woes

Postby philthehill » Mon Apr 29, 2019 5:45 pm

https://www.minisport.com/toltsynchro-s ... -tool.html

Whilst some of the classic Mini gearbox parts are useable in the Minor gearbox - checking the part numbers of the classic Mini and Minor part numbers for the 1st/2nd synchro hub they are not the same - so the sychro assembly ring in the link above may not be suitable but there is no harm in asking as suggested by oliver90owner


ndevans
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Re: Gearbox woes

Postby ndevans » Mon Apr 29, 2019 6:47 pm

I rang them-they said they didn't think it would work. :(
cheers N
'69 Traveller, 1275, discs.

philthehill
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Re: Gearbox woes

Postby philthehill » Mon Apr 29, 2019 8:05 pm

Here is your answer and very simple and very cheap :D

https://www.youtube.com/watch?v=xI9CNBndt54


ndevans
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Re: Gearbox woes

Postby ndevans » Mon Apr 29, 2019 10:47 pm

Hmm. Had too much red wine now, daren't give it a go! Job for tomorrow! Thanks.
cheers N
'69 Traveller, 1275, discs.


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