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SIII gearbox overhaul

Here are some pics. I don't think that the small indentation would prevent the ball from moving sideways thus stopping the block but I'm definately not the expert. Why is there more than one ball retaining groove? The inner spins with the outer so are the others there just as a result of machining or something - or am I just demonstrtaing my complete lack of competence?!!!

I'm really in need of some help here! (Obvious really- ha ha)
 

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Maybe I have the answer - the book says insert the blocks, radiused face outwards. That's what I thought I had done - there does seem to be a slight curved face one side... but on the other side the edges are chamfered and if this side is facing out then the edges don't pick-up and the blocks would seem to slide more easily.
Have re-assembled and off to try on mainshaft with the support of the synchro cones behind the blocks...

or am I wrong???
 
There is some wear on that, but I'd say it was still serviceable.

Those blocks around the sping have one side with a curve or radius in one axis, while the other side is bevelled on all edges. They must be fitted with the bevels towards the hub and the radius towards the outer sleeve. make sure the radius follows the arc of the circumference of the hub, ie. thin edges to the sides, thicker edges front and rear. If you put any of those blocks in the wrong way, the sleeve will seize on the hub like you have already found.
 
Snagger thanks - that will take me back to where I started - I must have done something wrong and then gone off on a tangent.

So bevelled side on the inside, curved outside and following the circumference of the gears - should be straight forward!!

Just had a misunderstanding about who was cooking tonight (guess who got it wrong), so investigations will re-start later!
 
secondjeremy - I think that refers to the best alignment of the inner and outer before the springs etc. are fitted.

Snagger - I have v carefully refitted, bevels on inside (next to springs) and radiused outside, BUT the radius / curve is along the length of the shaft ie in direction of travel as it moves 1st to 2nd and back. That seems to be much better as the front / rear edges are now slightly lifted away from the outer so that as they slide, there's no chance of any pick-up by the leading edge.
There's still chance to change but it makes sense to me. The workshop manual doesn't go to this detail though. What do you think?
 
That would mean that I have them turned 90deg from how you suggest. As they are the movement seems OK, a bit of a clunk but no gears are turning of course.

I have a whole day in the garage today so I'll disassemble and fit again as you suggest. Clearly I have to sort it out and be sure...

Otherwise, I have the layshaft ready, new mainbearing in the housing so really its re-assembly day today.:)
 
It is now sorted. Blocks are oriented as suggested (thanks Snagger) with curved face outwards and curved around the direction of shaft rotation.

The movement is much better because I have used emery cloth to restore the sliding surfaces on the inside of the outer as there was some burring which may have been contributing to the problem.

Manishaft reassembled, mainbearing and oil seal in housing (and in freezer) - about to press into case (sitting on Aga)

Thanks to all for help & comments :)
 
Can anyone advise on the next couple of problems I have found in my slow re-assembly of my box?

1) Fitted new input shaft and bearing to the bellhousing, but standing back and looking at it I think that the bearing might allow oil into the bellhousing. My old pinion has a bearing that looks sealed, whereas the new one is 'open'. Will it really leak past and is this OK?

2) As I start to tighten the mainshaft nut, it is pushing the transfer gear back against the oil thrower. As this happens the mainshaft rotation gets tight. When I put the necessary torque onto the nut will it continue to tighten and is this OK?


Thanks
 
1. Won't the clutch mechanism cover the bearings and contain the oil? There should be an oil seal inside the cover for the mainshaft (small hole underneath and ahead of the seal should be clear as it allows oil to drip down the gearbox face when the seal fails).

2. This doesn't sound right - have you got anything left over in the parts box?

Has the 1st/2nd gears/synchro rings fallen apart as you fitted the mainshaft? I found this job nearly impossible due to the difficulty in feeding the large gear on the back of the mainshaft past the reverse - and resorted to putting a pipe in the vice pointing slightly upwards, putting the front end of the mainshaft in it and feeding the casing over it. Still not easy but at least the shaft stayed at a constant angle and the casing was lighter.
 
As Jeremy said, the bearings are all normally open type, the seals being in the casings. There should be a seal inside the rear of the cast iron unit that covers the lay shaft and main shaft bearings inside the bell housing. Inspect it closely and feel it for brittleness, just in case it needs replacement.

Jeremy is also correct that tightening the rear main shaft nut should not change the gear box's resistance to rotation. My guess is that the oil thrower is not in its correct position on its sleeve, and is subsequently binding. The only other likely cause is that the end float on the first gear and its bush are wrong, and the first gear is seizing on its shaft.
 
Hi both, thanks for the replies. About the bearing - I did rush off this morning to buy another bearing with the shields in place - same as the one I removed, but the first replacement I had got from LR Series (bluebox) didn't have them. I have unfortunatley paid silly money for the new one (RHP) and I realise that I should have thought about the casting in the bellhousing which you quite rightly indicate will do the job. Oh well, lesson learnt.

About the mainshaft - firstly it really is difficult to get the gears past reverse whithout it coming apart - in fact I don't think it will go unless they are spaced. I did manage it on the third try and I have checked that it's all assembled again on the shaft.

I did check the end float several times before I put the spring ring on (as it's so hard to take off again) so I hope that it is a silly error with the oil thrower.

I'll let you know but won't be looking till later...
 
Sorry, spring ring is the other end. Anyway I think I have found the problem but not fixed it. See what you think:

1st gear is getting tight. It's a new one and whilst the bush it sits on is correct, sitting just below the ends of the mainshaft splines, the machined face of the gear is v slightly higher and so the thrust washer is tightening onto it rather than the splines.

When I try the original gear it is a little lower and doesn't appear to tighten when pressure is applied to the thrust washer.

It's hard for me to accurately measure the distance between the machined faces on the gears, but I think that the new one might be 7 thou thicker and that would explain it.

Does this sound plausible ?
 
Yes its sounds plausible - but who made the gear?

On mine there was a little wear on the face of the back thrust washer which made measurement difficult (caused by the splines I think but can't remember properly)

Having assembled it I then found the securing bolt pulled out of the Britpart layshaft! I now have a genuine one in there and hope to get it fitted next week.
 
The 1st gear is a Britpart...

I don't know how to proceed with this, either return it and try another or go for genuine

I can't see what else it can be..
 
If you have the old gear handy I'd assemble the shaft with it on and see if all is well - which should fix the blame on the Britpart gear.

Do you think another Britpart gear will be correct?

Series 3 gears aren't 'paired' like Series 11 so one can be obtained on its own - even a good used one. This should keep the price down.

LR Series sell genuine as such

http://www.lrseries.com/

As a matter of interest what was wrong with the original gear?
 
I do have the original gear and although I haven't fully re-assembled using it, I have had it on and off several times, along with the Britpart in order to work out what's happening, once you and Snagger had confirmed something was wrong.

When I fit the old one and push the thrust washer as hard as possible against the 'gear', it doesn't get hard to turn as it is touching teh end of the splines, whereas the new Britpart gear does and it is v slightly past the end of the bush. I don't have a micrometer (only vernier caliper) but I have attempted a measurement of thickness between both gear's machined faces and that's where I have found the difference between the two.

Do I think another Britpart will be the same? - I've got no evidence

Maybe I should return the Britpart, pay another £20 and buy genuine (not a lot extra on it's own but the whole gearbox overhaul is costing over £350)

What's wrong with the original? The dog teeth are well worn down and I thought it would be a wise move to change 1st and 2nd, although I haven't changed the synchro, only the springs.
 
Return the Britpart gear. It's not fit for purpose. rthe chances are that it's metalurgy is all wrong too, and it'll strip teath or wear through the case hardeneing very quickly anyway. I'll guarantee that a repacement Britpart gear will have the same faults.

If the original gear isn't damaged, use it, otherwise buy a genuine one from Dunsfold LR, PA Blanchard or LR Orphanage.

You now see why I started that Britpart boycott. Never, ever, trust their mechanical components - many don't fit, many leak, and some fail with catastrophic consequences, like failing brakes, shearing steering relays and so on. Don't put your life in the hands of cheap counterfeit parts.
 
Gulp!
I have a Britpart layshaft, Britishparts input shaft and Britpart 1st & 2nd gear ( but I did buy genuine synchro rings and 3/4 clutch!

Funny thing is I have re-assembled (for the nth time) and 1st gear is definately not tight so I don't know what I have done. There is some resistance on the shaft (and there is with the original 1st gear) but I'm probably feeling the thrower in the new oil seal.

Know I don't know what to do - I don't see how I can return all my none genuine parts to LR Series
 
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