If you have already tried brute force, blood, tears, WD40 and a lot of heat without success. This is my suggestion of a last resort
I needed to remove a seized bolt holding the gearbox and impellor housing together.
Using a stick welder, put a couple of blobs of weld on top of the seized screw/bolt head, and then weld a 10mm nut on top as well.
Once it was cooled you can undo the nut with a ring spanner and the bolt should easily come away with it.
This is particularly good for gearbox bolts as the gearbox is alloy and the bolt steel, therefore you can’t weld the nut to the gearbox and it will only attach itself to the seized bolt. You may need to make sure replacement bolts are available first though.
I cant see why this method using a welder cant be used on other corroded or rung-off fittings (so long as the fuel tank and all trace of fuel has been removed) the heat that is created by the welder is conducted down the bolt and helps to loosen it as well.
removing seized and corroded bolts and screws
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
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dbarrott
Gearbox endcap bolts.
The dreaded centre bolt holding the gearbox assembly came out without a struggle, but the lower bolt holding the end cap to the gearbox resisted all efforts and finally sheared its head. I thought that as this had happened it should then be an easy matter to remove the cap. Not so! the cap refuses to budge. Any ideas?
David
The dreaded centre bolt holding the gearbox assembly came out without a struggle, but the lower bolt holding the end cap to the gearbox resisted all efforts and finally sheared its head. I thought that as this had happened it should then be an easy matter to remove the cap. Not so! the cap refuses to budge. Any ideas?
David
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Dr.Lighthouse
- Posts: 30
- Joined: Thu May 25, 2006 10:29 pm
- Location: De Panne - Belgium
If there is 'one' instrument that might solve the problem of a seized bolt, it must be an impact screwdriver.
If used correctly, there's a fair chance that you can re-use the bolt after cleaning up the threat.
Oh, and to prevent seizing it in the first place:
use a bit of the good old copper grease when assembling.
If used correctly, there's a fair chance that you can re-use the bolt after cleaning up the threat.
Oh, and to prevent seizing it in the first place:
use a bit of the good old copper grease when assembling.
Or you could try the 'rocking' technique.
If you soak the offending bolt and its surroundings in penetrating oil for a few weeks (literally), then you can:
Squeeze onto the offending head the biggest Mole grip you can use. Get it good and tight. This is the best grip you're likely to get on the thing.
Apply liberal heat. Hotter than you think is safe, and hotter than that still.
Then rock the bolt first one way, then the other. Don't apply real brute force, just enough to provide a resistance. Each movement will move the bolt a fraction of a degree, and each movement will shift a few crystals of corrosion. Keep going for a few minutes, and eventually you'll feel a movement. Keep going, and sooner or later ( maybe 15 minutes! ) you'll feel a 'freeing off' of the siezed fastener.
Now you can begin to apply a real turning movement - you may have to shift the Mole grips.
This works like magic on magneto fixing screws, and nearly as well on gearbox cap fasteners.
The water pump housing centre screw sadly doesn't offer the same surface to a Mole grip. I'm still working on that one!
If you soak the offending bolt and its surroundings in penetrating oil for a few weeks (literally), then you can:
Squeeze onto the offending head the biggest Mole grip you can use. Get it good and tight. This is the best grip you're likely to get on the thing.
Apply liberal heat. Hotter than you think is safe, and hotter than that still.
Then rock the bolt first one way, then the other. Don't apply real brute force, just enough to provide a resistance. Each movement will move the bolt a fraction of a degree, and each movement will shift a few crystals of corrosion. Keep going for a few minutes, and eventually you'll feel a movement. Keep going, and sooner or later ( maybe 15 minutes! ) you'll feel a 'freeing off' of the siezed fastener.
Now you can begin to apply a real turning movement - you may have to shift the Mole grips.
This works like magic on magneto fixing screws, and nearly as well on gearbox cap fasteners.
The water pump housing centre screw sadly doesn't offer the same surface to a Mole grip. I'm still working on that one!
seized bolts
The other approach (which I've heard about but am still trying to set up) is left handed twist drills, in a drill press so that they stay vertical. Allied to penetrating oil every day for a week beforehand...... Does anyone have any ideas for this at a reasonable price - the domestic Clarke drill press is not reversible.
Donald A
Donald A
That Centrebolt - again!
I have a 1958 vintage 40+. The last time that centre bolt holding the exhaust flange to the gearbox was out was in the late 80s. It just took me 4 days to get it out again this week - here's another tool to try.
I cramped the skeg tight in a workmate set to it's lowest height. Did all the penetrating oil, 'ringing', and heat stuff a few times a day and still couldn't budge it with a hand driver or a power driver. Having read this thread I went on the web to try and get an impact driver but (fortunately!) the first company I tried they were out of stock. Tried one last go before going back on the web to locate an impact driver. This time I used a big old carpenters brace with a big screwdriver bit in it which exactly fitted the head of the machine screw. With the skeg cramped in the workmate set 'low' I could put a lot of weight on the brace to keep the bit in the slot and a brace will apply a lot of torque. Slowly it started to move and with liberal application of penetrating oil every time it moved a little, out it came with not much damage done, except to the head of the screw which is a trifle battered.
I've ordered stainless, and will be taking these bolts out at the end of every season and putting them in an oil bath - what a brilliant suggestion that was!
I cramped the skeg tight in a workmate set to it's lowest height. Did all the penetrating oil, 'ringing', and heat stuff a few times a day and still couldn't budge it with a hand driver or a power driver. Having read this thread I went on the web to try and get an impact driver but (fortunately!) the first company I tried they were out of stock. Tried one last go before going back on the web to locate an impact driver. This time I used a big old carpenters brace with a big screwdriver bit in it which exactly fitted the head of the machine screw. With the skeg cramped in the workmate set 'low' I could put a lot of weight on the brace to keep the bit in the slot and a brace will apply a lot of torque. Slowly it started to move and with liberal application of penetrating oil every time it moved a little, out it came with not much damage done, except to the head of the screw which is a trifle battered.
I've ordered stainless, and will be taking these bolts out at the end of every season and putting them in an oil bath - what a brilliant suggestion that was!
There is /was a guy called "BRIAN WINCH" who used to write articles in a model aircraft magazine.I faintly remember him disscusing the same sort of thing ( stuck steel fasteners in ally).If memory serves me he mentioned a way of dissovling the steel screw etc and leaving the ally untouched.
For the life of me i cant remember the method he mentioned,but i do remember he wrote his home in austraila, may be one of our ozzy freinds can track him down and find out how he done it.
Im sure he suggested useing some commonly obtainable substance but i just cant remember what !!! bugger
For the life of me i cant remember the method he mentioned,but i do remember he wrote his home in austraila, may be one of our ozzy freinds can track him down and find out how he done it.
Im sure he suggested useing some commonly obtainable substance but i just cant remember what !!! bugger
regards paul