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Pre A+ Idler Gear Installation Problem
https://www.ausmini.com/forums/viewtopic.php?f=2&t=99535		 Page 1 of 1
Author:  slide [ Tue Dec 17, 2019 9:33 am ]
Post subject:  Pre A+ Idler Gear Installation Problem
I’m finishing  rebuilding a 3 synchro 1967 S box and have a problem fitting the idler gear into the gearbox housing.

It is a 22G333 Mk1 S box with what I think are1 inch OD idler bearings in the gearbox and the clutch housing but it has the later idler gear with the unequal length 0.75 diam shafts (22G943), the same gear as were fitted to the later 4 synchro boxes.

The problem when trying to intall the longer of the idler gear shafts into the gearbox is that the end of the shaft hits the “ears” of the retaining circlip [51K3565] which stick up, meaning the shaft won’t go into the casing any further. The cirlcip fits snugly into its groove in the casing, but the ears protrude into space behind the bearing stopping the shaft sliding in the full amount.

Are the ears of the circlip meant to “lay down” more into the groove so s not to interfere with the shaft? Did the 4 synchro boxes with the same unequal shaft idler gear have this circlip on the inner end of the bearing too? MiniSpares don’t even list this circlip.

If I grind the ears down then how do you remove the clip in future?

Incidentally, I have an old worn equal shaft length idler gear from a non S 3 synchro box laying around and this fits into the casing ok because the shaft doesn’t reach the circlip.

 
Author:  Bill B [ Tue Dec 17, 2019 6:15 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
This issue has been discussed before - maybe here but elsewhere too.
The solution from another forum is fitting a "different" circlip but no details.
I have recently rebuilt a 12G333 box with later idler but didn't have problems with the circlip. However don't know what circlips I used.
Here is a photo ( bit dark) of a later 4 synchro gear, bearing and circlip.
The circlip doesn't go anywhere near the gear shaft. Do your circlips look like this?
Author:  lomin [ Tue Dec 17, 2019 6:31 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
Hi, best solution is different circlip, 2nd choice grind off ears, and it is easy to remove later, just tap a small drift into it, it will pop out as its not very secure at all cheers Lindsay Siebler
Author:  slide [ Wed Dec 18, 2019 8:30 am ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
Ok thanks guys. Did a bit of work on it last night after I got home from work, ground the ears down on the circlip with the Dremel and the shaft just passes through it now.

The 1967 box would have been originally fitted with the earlier equal length shaft idler gear , so this later uneven shaft gear must have been retrofitted at some stage. Not sure if there was even a circlip fitted when I pulled it down, it was some time ago now, I just installed a new 1” bearing and new circlip.

A couple of questions – 1) why did BL change to a longer shaft on one side of the idler gear? And 2) is there any real benefit in using the later gear?
Author:  drmini in aust [ Wed Dec 18, 2019 10:57 am ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
The longer shaft allows the bearings to be further apart for better support.
Author:  Bill B [ Wed Dec 18, 2019 12:02 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
Internet folklore from a Mk-1.forum.net thread on this subject (I hope I'm allowed to quote directly without infringement):

"Surely the "long peg" idler gear was fitted to the 3 sync boxes (on Cooper S at least) from early 1967, as a direct result of the failure of the earlier equal peg length type that caused Makinen's retirement from the 66 RAC. The same bearing was used but with a different circlip that allowed the longer peg to pass through it."
Author:  slide [ Wed Dec 18, 2019 12:13 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
So maybe it was the original idler gear fitted to the 67 S box after all.
Author:  Bill B [ Wed Dec 18, 2019 5:09 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
slide wrote:
So maybe it was the original idler gear fitted to the 67 S box after all.


The dates suggest it is possible.
This is what happens when you fit the early gear to a 4-synchro box (courtesy Mk1-forum.net):
Author:  slide [ Thu Dec 19, 2019 5:18 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
Yes I see, only half the roller bearing has the shaft sitting on it.

The circlip I have had ears that stuck up much higher, but it was the 3 synchro one so must have differed from the later type which from the photo would clearly allow the longer shaft to pass through.

The bearing and circlip also seem to sit much further back towards the gearbox than they appear to do on the 3 synchro.
Author:  Bill B [ Thu Dec 19, 2019 8:57 pm ]
Post subject:  Re: Pre A+ Idler Gear Installation Problem
slide wrote:
Yes I see, only half the roller bearing has the shaft sitting on it.

The circlip I have had ears that stuck up much higher, but it was the 3 synchro one so must have differed from the later type which from the photo would clearly allow the longer shaft to pass through.

The bearing and circlip also seem to sit much further back towards the gearbox than they appear to do on the 3 synchro.


I am also starting to realise the bearing on the gearbox side sits further towards to gears in the 4 synchro case.

If you don't learn something new everyday, you must be dead.

I wasn't able to find another part number for an alternative circlip. The Mini King's catalogue uses the p/n you mentioned in the first post for all the bearings but there has to be either another p/n or you have to chance finding a different shaped circlip. The circlips might actually have names for the different gripping methods.
By the way, the bearing O.D is quoted as 1.065inch.
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