Gearbox Reassembly Question 1

[Richard Pope]

I am reassembling my gearbox having refurbished it and despite meticulous notes, think I have a problem. I’m actually also converting this to add a J Type O/drive unit but that should be irrelevant – I have the correct new main shaft.  (My box is an October 1973 USA spec one.)

 

Picture 1 shows main shaft almost in box with rear main bearing not fully home in casing. Main shaft has a slot for a circlip currently adjacent to rear main bearing’s inner race and arrowed in red. My notes and Haynes manual shows a spacer washer should be between this circlip and the bearing’s inner race but I cannot see how to get one there and which one to use.

 

My repair kit has provided me with two circlips and two C washers – assume one set on the front first motion shaft but have not got there yet. Picture 2.

 

My original one marked in notes as from my non-O/d main shaft does not fit as it is too small a diameter and will not even go on my old main shaft to the correct place where the bearing would have sat – see picture 3. I must have made a mistake, I suppose.

 

My question is should there be a washer between the main shaft’s circlip and the inner race of the main rear bearing? If so, is it the C washer I have or a different one I don’t have. The C washer seems a bit small, actually.

Internally, all cogs, bushes, washers, etc. are all fitted correctly on the main shaft and there is a thrust washer that faces the main bearing’s inner race on the inside. The main bearing is very, very tight on the new shaft, by the way.

 

Follow-up question is where do I set the position of the rear bearing on the main shaft? I assume the rear bearing should be tight (not too tight) fitting to the rear circlip with or without the washer I am questioning above.

 

Answers / pictures / references to any web site info appreciated. I have the Buckeye articles but they are not clear at this point.

[John L]

There should be a spacer behind the circlip at the rear, but it is determined by the clearance of the gear and bush in front of that rear bearing, do you not have the manual, its available here,  http://vitessesteve.co.uk/Servicemanuals

John

[Richard Pope]

Thanks John,

So you are saying that in my photo 1 there is a washer between the circlip location pointed to and the bearng's inner race? I do have this manual and PDF page 238 step 20 appears to imply there is one. What's a snap ring? Is it the large circlip on the bearing itself?

My photos of the stripping down appear not to show this washer but it is not that clear (typical). I don't have this washer in my strip-down collection and I cannot push the bearing further down the main shaft to provide room for it either. I think the reason why I cannot make room for it is because on the inside of the gearbox, the gears + thrust washer is stopping this happening. I'm up against a stop.

Still not quite sure what to do.

 

[John L]

I think there are differences with overdrive and std gearbox.

As long as you have checked the height of the bush in the gear, and set the bush alone on the shaft with the front washer, bush and rear washer and fitted the bearing and the circlip and knocked the shaft forward to get the bearing back against the rear circlip, and the bush has the right amount of running clearance, it would seem that there isn't a washer under the rear circlip, I looked in Rimmers for part numbers and appears the washer is for std gearbox not overdrive.

Hope that's clearer?

John

[Richard Pope]

Thanks again John,

Yes that seems clear enough. As it happens, I have now found this distance washer (from my original stadard gearbox) in the storage wrong box and was labeled up with the same name as the one I could not fit so I had picked the wrong one. Thus I now have this distance washer.

I'm taking the main shaft out again and will start this step over again and agree, if I measure correctly I will work out if I need it or not. This distance washer is quite thick (2mm?) so it should be obvious.

The bearing on the mainshaft is very tight fitting so getting it off is the new challange.

Hindsight is wonderful!

[John L]

Just make sure when you try and remove that tight rear bearing, only press on the inner bearing race and use a press if possible, or you could dent the bearing with the balls, and make run roughly, some are not as hard as you think!

John

[dingle]

Richard-You might find these articles on rebuilding the gearbox helpful, as they include the dimensions of the various washers used.  https://www.buckeyetriumphs.org/gearbox 

Berry

[rvwp]

Hi Richard,

I see from your picture that the Laygear seems to be in position whilst you are trying to fit the Ist motion drive shaft. This is impossible. It should not have been possible to withdraw the Ist motion shaft without dropping the laygear into the bottom of the box?

Fitting the main shaft with rear main bearing with gear, and Ist motion gear must be completed with the Laygear loose in the bottom of the box. 

Ideally a support tool should be used to centralise the front of the mainshaft when pressing in the the rear bearing otherwise it may well be cocked and jam!

Turning the box upside down, engaging the laygear with the mainshaft,  and aligning the laygear pushing the layshaft through the casing, keeping the thrust washers in place, is the final job. What fun!

Rich

[Richard Pope]

Thanks John. I do have a press so can use that.

Berry, yes I have them and used them. Thanks.

Rich, see my Question 2 post. Thanks.

 

[Richard Pope]

Re-asking a question, please. I think I do need the washer (above conversation) but if not, the same question applies.

Does anyone know how to align / adjust the main shaft with the outer face of the bearing's inner race?

Photo shows position with arrow (I know this does not show washer and circlip) of how close to align this.

Haynes manual gives a 4.87mm distance but Buckeye says snug fit.

When I finally put the main shaft into position through the center bearing, how should I adjust it? Should I simply push the main shaft rearwards until washer is hard up against  the bearing's inner race outer face? I.e. Simply push the main shaft as far as it will go against the inner race's face.

If I do this, I assume the thrust washer and gear on the main shaft inside the gearbox at its rearmost end automatically and has the correct float between it and the bearing's inner face. There is no way to measure this in situ as far as I can see.