Gearbox rebuild

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Re: Gearbox rebuild

Postby 56G80S » Wed Jan 09, 2019 2:34 pm

In support of the other posts suggesting DIY. I did a GB box quite some time ago when I knew even less than I do now. Only one error, which I refuse to elaborate on as it was purely down to frustration, time pressure and anger. This had no impact on the effective working of the 'box. I don't like it as much as the wrong for year AMC that I put back in. If I find time, though, the very hard used AMC will be coming out for a refurb and the Burman going back in. Just need to follow the threads on this Forum about using CP clutch with GB 'box.

Also reinforce the value of the smartphone camera, you really can't take too many pics.

Johnny B

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Re: Gearbox rebuild

Postby Mick D » Wed Jan 09, 2019 2:44 pm

56G80S wrote:you really can't take too many pics.


Spot on||

Take photos at every stage of the disassembly - they will pay dividends :)

Regards Mick

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Re: Gearbox rebuild

Postby quizmaster » Wed Jan 09, 2019 3:15 pm

Mick D wrote:
56G80S wrote:you really can't take too many pics.


Spot on||

Take photos at every stage of the disassembly - they will pay dividends :)

Regards Mick


Forget the rebuild, once you have taken the photos instead help the poor quizmaster, who has nearly run out of ideas for the quiz after 6 years, by sending an image to quiz@jampot.com
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Re: Gearbox rebuild

Postby oldandsmelly » Wed Jan 09, 2019 3:20 pm

Hi Mick

I use adjustable reamers and make very small adjustments each pass.

cheers
Bruce

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Re: Gearbox rebuild

Postby SPRIDDLER » Wed Jan 09, 2019 4:56 pm

If you look in Christians Archive under 'Books'.......'Technical'........'Transmission'..........'Burman' you'll arrive here:

http://archives.jampot.dk/technical/Tra ... on/Burman/

where you'll find several helpful and illustrated CP rebuild articles including this one (link below) which although entitled 'Burman B52 Gearbox rebuild.pdf' it is actually for a CP 'box.....

http://archives.jampot.dk/technical/Tra ... ebuild.pdf
I poke badgers with spoons.

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Re: Gearbox rebuild

Postby Andy51 » Sat Jan 12, 2019 4:22 pm

Mick, it was a while ago when I rebuilt my 'box. As I remember it, I made a shouldered drift from a suitable piece of bar and used a vice to press the bearings in. I used bushes from Jampot spares; they were an interference fit and loctite is unnecessary but they do close up slightly, hence the need to bore or ream. Reaming is as good a method as boring to size the bore, but if you are using a hand reamer, make sure it does not wander or go in slightly skewed. An alternative method, possibly slightly easier, is to mount the bushes on a mandrel in the lathe (3 jaw chuck is ok if you turn the mandrel to size in the chuck - push fit in bush) and finish the outside of the bush to a light push fit in the gear bore. Secure with loctite. This obviates the bush closing up and should leave it a nice running fit on the shaft - I used this method to fit swinging arm bushes as I did not have a piloted reamer. I find turning the exterior like this easier than clocking the gear true in a 4 jaw chuck and boring - it is usually easier to measure outside dimensions than inside ones. Hope this helps, Andy

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Re: Gearbox rebuild

Postby Mick D » Sat Jan 12, 2019 4:55 pm

Thanks Andy

Very useful information :beer:

I've done quite a bit of research on this subject now and have formed a cunning plan: Heat the sleeve gear and freeze the bushes, insert using a vice with the aid of a stepped mandrel and Loctite, try the main shaft for fit, (I've seen reports that a worn shaft, 0.859" in my case, needed no additional reaming), ream to size with an adjustable reamer, (I can set the sleeve gear up in my lathe and use a tail centre to keep the reamer aligned).

Fingers crossed

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Re: Gearbox rebuild

Postby g80csp11 » Sat Jan 12, 2019 5:19 pm

Just about to start my CP box rebuild tonight . I don't need it running for 2 weeks to go down to the Talmag
What could possibly go wrong . its not unusual to be working late the night before

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Re: Gearbox rebuild

Postby SPRIDDLER » Sat Jan 12, 2019 6:03 pm

g80csp11 wrote:Just about to start my CP box rebuild tonight . ........ its not unusual to be working late the night before


What, again? You only did that 'box on your '46 last year...

Image

You'll have it in the kitchen again I suppose now that you've finished the twin ?

Image

At least you have some room in the kitchen .......

Image
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Re: Gearbox rebuild

Postby spookefoote1956 » Sat Jan 12, 2019 6:29 pm

Some of the tools in the photos are a mystery to me although I am most familiar with the wooden stick with the big metal bit on the end. From a health and safety point of view keep your thumb away from the metal bit and always wear a condom.
हरे कृष्ण हरे कृष्ण
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