Welding a gear box (non boaty)

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peter2407

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My wife's mini developed a problem with the gearbox. Essentially the casing plate between the gearbox and the clutch has developed a hole c. 5cm in diameter. I do have the piece that fell out. Question is can what I assume is a cast unit, have the piece welded back on?
 
peter2407 said:
My wife's mini developed a problem with the gearbox. Essentially the casing plate between the gearbox and the clutch has developed a hole c. 5cm in diameter. I do have the piece that fell out. Question is can what I assume is a cast unit, have the piece welded back on?
Click to expand...

Why and what does it do? If it just keeps the oil in, an adhesive might be better.

The problem with welding is that the whole lump will have to be heated to quite a high temperature. There may also be some distortion.
 
peter2407 said:
My wife's mini developed a problem with the gearbox. Essentially the casing plate between the gearbox and the clutch has developed a hole c. 5cm in diameter. I do have the piece that fell out. Question is can what I assume is a cast unit, have the piece welded back on?
Click to expand...


Importantly, why is there a hole? Have you fixed that?
Graham is right, you'd be better to stick the bit back in. Welding is possible, but is likely to be expensive to get it done right + the box might hace to be stripped, in which case another casing + internals would be a better bet
 
+1 A good 2part adhesive. A friend once had a crack in the sump of a MK2 Jag held untill the car was sold 2 or 3 years later.
Graham_Wright said:
Why and what does it do? If it just keeps the oil in, an adhesive might be better.

The problem with welding is that the whole lump will have to be heated to quite a high temperature. There may also be some distortion.
Click to expand...
 
We used to weld bits on to Rover V8 aluminium engine blocks. As has been said though, it's not straightforward, and the bits we were welding on didn't need to be in precisely controlled positions. If the bit you want to weld carries a bearing (or something like that), I'd go for a second hand box from a scrapper.
 
Thanks all.

Root cause - known issue with Minis of a certain age. Seems to be a bolt or such that loosens from somewhere between the clutch and the gearbox shears off/falls out.

Adhesive - any recommendations?
 
I would determine if the section needing repaired is load bearing or not. You could try lumni (sp) welding rods applied with a plumbers blowtorch. You would need to localise the repair area with welders paste (don't remember the name) that stops the heat from spreading through the housing.
 
It can be welded using TIG welding without pre-heating. I had a cracked lug repaired on an alloy gearbox last year for £35.


gearboxcrackwelded01.jpg
 
ronmarson said:
"JB Weld" from any good auto shop.
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Ron - thanks. looks ggod. reading some Amazon reviews, it seems to be the dogs danglies for any non stress repair. Does the panel think that putting a metal bit back into a gear box casing counts as non stress? From what i can see, its not a moving part...
 
peter2407 said:
Ron - thanks. looks ggod. reading some Amazon reviews, it seems to be the dogs danglies for any non stress repair. Does the panel think that putting a metal bit back into a gear box casing counts as non stress? From what i can see, its not a moving part...
Click to expand...

It really depends what it is supposed to do. Any chance of a photo? Was there anything attached to it?
 
Used it to fill the enlarged hole on my Jaguar 22 swing keel, lots of stress there, but it seems to be OK after 4 years. It's a bit runny and you would have to put the bit back to give it something to stick too. Don't expect to get the job done in one go, I filled a bit and waited for it to set then had another go.
The joys of retirement, lots of time.
Ron
 
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