Gearbox outer case assembly Clearance

Samuel Whittle · Jan 15, 2021

Hi everyone,

I am reassembling an outer gearbox cover on a 72 Commando. The old one fits fine but was all banged up so I ordered a new one from Andover Norton, I know the assembly was exactly as before but now it is not clearing the clutch cable lever (it was before). Could the outer gearbox cover I got be shallower?

I was also surprised to see he amount of inconsistency between the old inner and new outer casings. Old one appears to be quite wider in some areas. They don't match perfectly...

seattle##gs · Jan 15, 2021

You might have to do some minor shaving of either the lever or case. Sometimes they are very close. I have not seen a new case.

Samuel Whittle · Jan 15, 2021

seattle##gs said:
You might have to do some minor shaving of either the lever or case. Sometimes they are very close. I have not seen a new case.

At the point where the clutch lever rubs, the new case is 4mm shallower than the older one...that seems like a lot to be different!

L.A.B. · Jan 15, 2021

Samuel Whittle said:
I am reassembling an outer gearbox cover on a 72 Commando. The old one fits fine but was all banged up so I ordered a new one from Andover Norton, I know the assembly was exactly as before but now it is not clearing the clutch cable lever (it was before). Could the outer gearbox cover I got be shallower?

If that's the new cover then I can't see where the problem is when compared to my own, below?

MichaelB · Jan 15, 2021

Maybe it's the picture but the cable angle doesn't look right.
Could be the cable boss on the new cover is slightly different than the old cover which results in a different cable angle.
May have to realign the adjuster with the new cover, which may give more clearance.

Samuel Whittle · Jan 15, 2021

L.A.B. said:
If that's the new cover then I can't see where the problem is when compared to my own, below?

That is just the photo. The cover won't go all the way on because it fouls out on the lever. Touches right down on it.

Samuel Whittle · Jan 15, 2021

MichaelB said:
Maybe it's the picture but the cable angle doesn't look right.
Could be the cable boss on the new cover is slightly different than the old cover which results in a different cable angle.
May have to realign the adjuster with the new cover, which may give more clearance.

Do you happen to have an example of what you mean when you say, "the cable angle doesn't look right". What would you expect it to look like? I am no expert which is why I was hoping the photos might help to spark some ideas!

MichaelB · Jan 15, 2021

The adjuster fork should line up with the cable boss.
It looks like the cable pulls to the right, which means the adjuster needs to be clocked left a little.
With the cover still on, make a mark with a Sharpie on the inner cover where the cable boss is.
Remove the cover and see if the fork lines up with the mark, adjust accordingly.
BTW, this usually doesn't affect the install of the cover, just the operation of the clutch.
Maybe your cover is shallower. Would be interesting if you could take some measurements and compare.

Samuel Whittle · Jan 15, 2021

MichaelB said:
The adjuster fork should line up with the cable boss.
It looks like the cable pulls to the right, which means the adjuster needs to be clocked left a little.
With the cover still on, make a mark with a Sharpie on the inner cover where the cable boss is.
Remove the cover and see if the fork lines up with the mark, adjust accordingly.
BTW, this usually doesn't affect the install of the cover, just the operation of the clutch.
Maybe your cover is shallower. Would be interesting if you could take some measurements and compare.

Okay, I will give that a shot. Well like I said, where the clutch lever fouls out, it is almost 4mm shallower. Thats a lot....I mean I could certainly shave some out and maybe cut 1 mm off the clutch lever but this is an Andover norton product. Thats seems pretty far off, doesn't it? https://andover-norton.co.uk/en/shop-details/15392/gearbox-outer-cover-assy

marshg246 · Jan 15, 2021

Samuel Whittle said:
Do you happen to have an example of what you mean when you say, "the cable angle doesn't look right". What would you expect it to look like? I am no expert which is why I was hoping the photos might help to spark some ideas!

The cable should be straight - it looks like the actuator is too far clockwise by a good bit.

Torontonian · Jan 15, 2021

marshg246 said:
The cable should be straight - it looks like the actuator is too far clockwise by a good bit.

Re-align the arm to cable pull where it is a straight pull and is happiest. Tightening up the big ring can set alignment things off so double check the final cable pull path. Never seen a new AN outer cover. I put a dab of grease to the cable end here seeing as lubrication upper outer cover is somewhat lacking.

seattle##gs · Jan 15, 2021

The cable does look way to the right. It is very importand to have it lined up dead on with the cable entrance point on the inner cover. Any little bit off makes for a noticeable harder pull. Sometimes it takes several attempts to get it right but you must do it.
As for clearence you might try a second gasket. I have never tried that

Torontonian · Jan 15, 2021

seattle##gs said:
The cable does look way to the right. It is very importand to have it lined up dead on with the cable entrance point on the inner cover. Any little bit off makes for a noticeable harder pull. Sometimes it takes several attempts to get it right but you must do it.
As for clearence you might try a second gasket. I have never tried that

I use a peen punch into the soft aluminum inner case , and when the arm and cable locates for a straight pull, I tap it to mark for the future. Because there will always be the future.

EstuaryBoy · Jan 16, 2021

Daft question (my forte)... But is this assembly 'loaded' from the rear: I.e: Is there pressure on the actuating arm from the pushrod as if the clutch was assembled?
Only ask as the arm won't travel in the correct arc without it....

jan nelder · Jan 16, 2021

MichaelB said:
The adjuster fork should line up with the cable boss.
It looks like the cable pulls to the right, which means the adjuster needs to be clocked left a little.
With the cover still on, make a mark with a Sharpie on the inner cover where the cable boss is.
Remove the cover and see if the fork lines up with the mark, adjust accordingly.
BTW, this usually doesn't affect the install of the cover, just the operation of the clutch.
Maybe your cover is shallower. Would be interesting if you could take some measurements and compare.

I have two (old ) versions of the outer cover for that box, one of which is not interchangeable with the other. ( probably pre Commando).

olympus · Jan 16, 2021

With my new cover the arm was touching.... with the old cover it wasn't Mr. Dremel soon sorted it
AN weren't aware of any issues with the batch of covers and to be fair did offer to replace
With all the posit hassle & lockdown i couldn't be asked to send it back

Samuel Whittle · Jan 16, 2021

olympus said:
With my new cover the arm was touching.... with the old cover it wasn't Mr. Dremel soon sorted it
AN weren't aware of any issues with the batch of covers and to be fair did offer to replace
With all the posit hassle & lockdown i couldn't be asked to send it back

Glad it wasn’t just me. So yours too was considerably shallower but you just shaved out the inside? Okay I may just go that route then. Thanks!

marshg246 · Jan 16, 2021

I really sure that if you correct the alignment of the cable that you'll have no issue with the cover and will improve the clutch action . The arm will be in the inspection hole and won't be close to anything. It is easier to do with the correct tool. Promise to send it back and I'll send you one.

Samuel Whittle · Jan 16, 2021

marshg246 said:
I really sure that if you correct the alignment of the cable that you'll have no issue with the cover and will improve the clutch action . The arm will be in the inspection hole and won't be close to anything. It is easier to do with the correct tool. Promise to send it back and I'll send you one.

I went back this morning to take a look after everyone responded and it was just a really deceiving photo. It appears to be dead on to me.

As for the case being to shallow. I guess I will need to shave it. This is the state at which it fouls out and has about 3mm left to go.

marshg246 · Jan 16, 2021

Samuel Whittle said:
I went back this morning to take a look after everyone responded and it was just a really deceiving photo. It appears to be dead on to me.

As for the case being to shallow. I guess I will need to shave it. This is the state at which it fouls out and has about 3mm left to go.

You're there so I'm not saying your wrong, but I still think it is wrong. The way to tell for sure is the mark the inner cover where the cable enters the outer cover. Remove the outer cover and the actuator arm. Then using a flat piece of metal against the inside of the slot the actuator rides in, see how you line up. If that's right, the other possibility is that the rod, ball and actuator are not properly engage and the actuator is too low - it seems a little low in the picture. I realize it worked with the old cover but there are a lot of variables - rod adjustment, cable hole angle, cable hole placement, inspection hole placement, and of course, the wall thickness you are thinking about. My concern is that you have a long way to go to get the cover on and I've replaced them without any trouble.

Gearbox outer case assembly Clearance

Samuel Whittle

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