Hi I am having trouble trying to remove the drive spline shaft and bush from my century 100 gearbox. Can any body tell me the correct way to do it. I've used heat and a drift and lots of effort and gave it a rest tried again lots heat and a drift and effort again and so on but it wont budge. Any advice would be welcomed.
Cheers
100 Century Gearbox Problem
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Still trying
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headdownarseup
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Re: 100 Century Gearbox Problem
By "drive spline shaft" do you mean the pinion and its bushing? Direct drive or clutched? Any pics so we can see what you're talking about?
Word to the wise here, ONLY remove this if you ABSOLUTELY HAVE TO. If there is only small amounts of play fore/aft and left/right (and by small i mean less than 1mm movement in any direction as measured by the naked eye) then leave it well alone. This could end in tears and a broken gearbox. Much easier to keep topping up the oil level instead.
If after your assessment of the situation proves to have more than acceptable play, then it's out with the blow torch. Oxy-acetylene works well as you're going to need some SERIOUS HEAT to get this to budge. Using a drift of some sort (not too hard either, brass works quite well as it's a bit softer if you can find anything that will work) will hopefully start to get things moving, BUT go easy as there are a few delicate threads to try and avoid in there i.e the end cap.
I have a few spare good second hand pinions with bushes if you're successful and you need one.
Keep me posted with you progress, i hope you get it out but it can be a *****??"!!
Jon
Word to the wise here, ONLY remove this if you ABSOLUTELY HAVE TO. If there is only small amounts of play fore/aft and left/right (and by small i mean less than 1mm movement in any direction as measured by the naked eye) then leave it well alone. This could end in tears and a broken gearbox. Much easier to keep topping up the oil level instead.
If after your assessment of the situation proves to have more than acceptable play, then it's out with the blow torch. Oxy-acetylene works well as you're going to need some SERIOUS HEAT to get this to budge. Using a drift of some sort (not too hard either, brass works quite well as it's a bit softer if you can find anything that will work) will hopefully start to get things moving, BUT go easy as there are a few delicate threads to try and avoid in there i.e the end cap.
I have a few spare good second hand pinions with bushes if you're successful and you need one.
Keep me posted with you progress, i hope you get it out but it can be a *****??"!!
Jon
Re: 100 Century Gearbox Problem
I have a pinion shaft and bush to replace on an early 102 box. My plan is to weld a cross bar to the square end and drill and thread each end and use two bolts to push against the top of the box drawing the shaft out. I can grind the weld off later but more likely to toss. Will heat but probably not to the extent of using oxyacet. I'll take some photos when I embark on this exercise.
I have considered using the existing threads on the box, with bolts, to unscrew against the cross bar but considered them too short and fragile.
I have considered using the existing threads on the box, with bolts, to unscrew against the cross bar but considered them too short and fragile.
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headdownarseup
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Re: 100 Century Gearbox Problem
Only one problem i can see with that method Hugz.
You might end up distorting the gasket face on the pumphousing using a makeshift press tool of sorts. The material on older 102 gearboxes is quite soft and doesn't stand up well to heavy force as they dent and bend quite easily. I have a couple of scrap boxes all bent out of shape where somebody has had a go at it before. Worst case scenario is they'll crack and break off into big bits that become quite difficult to weld back together again
I prefer to heat the bugger bloody hot and give it "what for" (carefully of course) in a soft jaw vice preferably with wood either side to protect the aluminium.
OR you could try this.
With as much of the gearbox internals stripped out, find yourself a chunk of railway sleeper or similar and drill a 1.5" hole through it. Place your gearbox pumphousing face downwards against the wood (for protection) with the top of the pinion aimed into the pre drilled hole,this might give you a better swing with a drift to remove that stubborn pinion.
Jon
You might end up distorting the gasket face on the pumphousing using a makeshift press tool of sorts. The material on older 102 gearboxes is quite soft and doesn't stand up well to heavy force as they dent and bend quite easily. I have a couple of scrap boxes all bent out of shape where somebody has had a go at it before. Worst case scenario is they'll crack and break off into big bits that become quite difficult to weld back together again
I prefer to heat the bugger bloody hot and give it "what for" (carefully of course) in a soft jaw vice preferably with wood either side to protect the aluminium.
OR you could try this.
With as much of the gearbox internals stripped out, find yourself a chunk of railway sleeper or similar and drill a 1.5" hole through it. Place your gearbox pumphousing face downwards against the wood (for protection) with the top of the pinion aimed into the pre drilled hole,this might give you a better swing with a drift to remove that stubborn pinion.
Jon
Re: 100 Century Gearbox Problem
I was going to put a shim ie 50c piece (half crown) between box and bolt. Also I would screw it down slowly and leave overnight and then another half turn and so forth until it releases. I've learnt my lesson about hitting seagulls.... They don't respond well 
Re: 100 Century Gearbox Problem
I think Hugo idea has merit, if a tool could be designed similar to a valve lifter to allow the pinion to be pulled out, then it will avoid the risk of damage by using a drift and big hammer.
So a clamp could put pressure in place perhaps helped by heat?
So a clamp could put pressure in place perhaps helped by heat?
Last edited by Oyster 49 on Thu May 12, 2016 11:12 pm, edited 1 time in total.
Re: 100 Century Gearbox Problem
Actually I was expanding on your idea Adrian and discussion with Charlesuk on Seagull's original pinion removal tool. Getting a grip on the shaft is the difficult bit hence welding which is a bit terminal. Depends if you are going to reuse it. I can't think of any reason to remove it if you were not going to replace.
Last edited by Hugz on Thu May 12, 2016 11:06 pm, edited 1 time in total.
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Charles uk
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Re: 100 Century Gearbox Problem
Look up slide hammer on the net.
Make it idiot proof and someone will make a better idiot.
Re: 100 Century Gearbox Problem
Yes, but how do you hold the slide hammer on the drive shaft?
Re: 100 Century Gearbox Problem
My thoughts to
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Charles uk
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Re: 100 Century Gearbox Problem
Now that will depend on which pinion shaft your trying to hold on to.
On a Marston pinion which is round I'd use an ER25 1/2" collet & holder, sealed box pinions can be screwed onto, but after that there are a multitude of pinion lengths on the 3/8" square drive version & everyone will come up with their own improved version, but Hugo's "weld it on, & grind it off" suggestion might well be the most cost effective answer.
On a Marston pinion which is round I'd use an ER25 1/2" collet & holder, sealed box pinions can be screwed onto, but after that there are a multitude of pinion lengths on the 3/8" square drive version & everyone will come up with their own improved version, but Hugo's "weld it on, & grind it off" suggestion might well be the most cost effective answer.
Make it idiot proof and someone will make a better idiot.
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Still trying
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- Location: Beachmere QLD Australia
Re: 100 Century Gearbox Problem
Hi and thanks for the feedback on the gearbox issue. In the attached photo you can see the almighty gap between shaft and bush and the flogged out teeth on the gear, she's had it. I'll persevere with it till I get it out but then what? Thanks to headdownarseup » for the info about replacement parts you have if I'm successful I'll be in touch. I have a question to ask as sparks and carbs are all I really know about when it comes to 2 strokes.I saw an ad on Ebay selling a gearbox and it said " suites 40 plus and 100 century" is it true that they have the same gearbox? Please click link to view photo. This is the first time I've done this link thing so I hope it works.
Cheers
Cheers
Re: 100 Century Gearbox Problem
I have removed (and replaced) a couple of pinion bushes on my direct drive century and a featherweight in the past simply by baking them in the kitchen oven.
Clean it up and degrease as much as possible first.
Fan setting about 220 centigrade was just about hot enough and a bit more controlled than blowtorch.
When removed from the oven I turned it over ready to apply a drift to the pinion and the bush just fell out of the water pump flange end.
Depending on the degree of "honeymoon fit" between the bush and housing you may need a slightly higher or lower temperature.
This method is really useful when re-inserting the bush as it is much easier to get the dimple in the bush aligned with the locking set-screw that holds the gearbox end-cap on. Especially if you chill the bush in the deep freeze first.
It will of course wreck any rubber seals and the paint finish. But if you are refurbishing you will be replacing those anyway.
And you will need to bake a really garlicky stew afterwards to rid the kitchen of the smell of roast EP140!
Clean it up and degrease as much as possible first.
Fan setting about 220 centigrade was just about hot enough and a bit more controlled than blowtorch.
When removed from the oven I turned it over ready to apply a drift to the pinion and the bush just fell out of the water pump flange end.
Depending on the degree of "honeymoon fit" between the bush and housing you may need a slightly higher or lower temperature.
This method is really useful when re-inserting the bush as it is much easier to get the dimple in the bush aligned with the locking set-screw that holds the gearbox end-cap on. Especially if you chill the bush in the deep freeze first.
It will of course wreck any rubber seals and the paint finish. But if you are refurbishing you will be replacing those anyway.
And you will need to bake a really garlicky stew afterwards to rid the kitchen of the smell of roast EP140!
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headdownarseup
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- Location: bristol
Re: 100 Century Gearbox Problem
That gearbox (to my eyes anyway) is "Toast". Fit for the scrap bin.
Is it a clutched type or direct drive (have you got some better pics?)
I'll let you into a little secret so dont tell anyone now.
shhh. i've got perhaps nearly 40 odd gearboxes stuffed down the side of the shed waiting to be stripped and assessed. Bargepusher types,conventional clutched types, direct drive 40plus/century types and a few more besides. I'm sure i can find you a better one than that for little cost. If not certainly the bits to build another better one.
If it were me, i'd start again with a more solid looking gearbox rather than waste my time trying to repair a "wreck". (been there and done that)
Always happy to help out a fellow seaguller.
Jon
Is it a clutched type or direct drive (have you got some better pics?)
I'll let you into a little secret so dont tell anyone now.
shhh. i've got perhaps nearly 40 odd gearboxes stuffed down the side of the shed waiting to be stripped and assessed. Bargepusher types,conventional clutched types, direct drive 40plus/century types and a few more besides. I'm sure i can find you a better one than that for little cost. If not certainly the bits to build another better one.
If it were me, i'd start again with a more solid looking gearbox rather than waste my time trying to repair a "wreck". (been there and done that)
Always happy to help out a fellow seaguller.
Jon
Re: 100 Century Gearbox Problem
I gotta agree with Jon. I do not think i would spend the time trying to repair that one. Must be easier and cheaper to get a complete replacement gearbox.