Stud SERIUOSLY siezed on gear casing

rustybouy

rustybouy

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Now then, iv'e been overhauling my outboard, and have pretty much stripped it all down, iv'e cleaned my carb etc etc. but i cannot get my lower gear casing off.

i did post before about this "(cannot find impeller location) " got some great advice, but after much hammering and lubricating, i still cannot get this gear casing of, iv'e consulted all the diagrams at boat library and and boats.net, so i know what im dealing with, but this stud is obviously corroded really badly,must be the whole aluminum/steel thing,i have it soaking in fresh water at the moment, any other ideas aprt from heating it up? any tricks ive missed to get this bugger out?

Pete
 
Soak in WD40, or similar. Otherwise heat, and be very gentle, or it'll snap, and you'll be drilling for hours...
 
WD40's as good as any other penetrating oil, being kerosene based. Humble 3 in 1 is probably the best though.

I was totally amazed at the effect of a drop of brake fluid on a stubborn steel bolt in an alloy motorcycle engine casing. The bolt had actually snapped and I was using an ez-out, kind of a left hand tap. I'd filled the hole with brake fluid the night before and the bolt-end just spun out with very little effort. The trick for you will be actually encourageing the penetrant to go where you want it, try making a funnel with plasticene.

Someone is bound to chirp up with WD40 is not a proper penetrating oil and brake fluid is corrosive; none of which is true.

Good luck - !
 
Alum in solution will eat steel, its a well used method of removing broken taps and the stupid cheap "easy out" things that snap as soon as you look at them. Eats the steel and leaves the ally/anything non steel alone but its not fast.
 
Drastic but....

After snapping a stud that was seized into an alloy casting (in this case the binnacle ) I managed to release the remnant by cutting a fine slot with a cheap version of a mini cutting wheel in a drill. The slot is cut down the casting along the line of the bolt and enables the penetrating fluid to do its job. There is still plenty of material left for the replacement stud to hold. I don't know if this approach is possible in your case but I was amazed how easily I was able to turn out the headless stud with a pair of grips after making the slot in the side.
The wheel is about 40mm diam and say 1mm thick.
 
After the penetrating oil as soaked for a few days, then time to apply the heat.

If this was me I would use a gas torch with a very fine and very hot flame. Heat the stud close to the thread as possible whilst applying firm but steady torque to undo the stud. The idea is to expand the steel stud within the aluminium casing. The expansion breaks the thread free. The penetrating oil will then get in and the stud may come loose as soon as the heat penetrates.
 
If you have part of the stud protruding by far the best method to remove it is to firstly soak for a minimum of 24 hours with penetrating fluid (whatever you find the best), if you're not in a hurry leave it for as long as possible.
Then using a mig welder, weld a nut onto the remaining part of the stud, or thin bar about 12 inches long. You can then use a socket to undo the nut, or the bar will give a good lever if there isn't enough thread left to weld a nut on.
Welding heats the object the stud is stuck in and usually gives it enough expansion to get the stud to move.
I'm not saying this will work in every case but has helped me out on many occasion!
 
superheat6k said:
After the penetrating oil as soaked for a few days, then time to apply the heat.

If this was me I would use a gas torch with a very fine and very hot flame. Heat the stud close to the thread as possible whilst applying firm but steady torque to undo the stud. The idea is to expand the steel stud within the aluminium casing. The expansion breaks the thread free. The penetrating oil will then get in and the stud may come loose as soon as the heat penetrates.
Click to expand...

Have to disagree with that, that is bad advice. If the stud is heated in favour of the ally casing the stud will expand making it tighter and even more difficult to remove!!

If you use heat, play the heat on the ally casing, high heat, short time, before the heat transfers to the stud, then work quickly to attempt to remove the stud, but there is no guarantee it will work.
 
I've never tried using heat to shift something like this. It will be interesting to see if it works. I did have cause to consider the effects of a 600°C temperature change on an assembly containing stainless steel and aluminium parts though and well the coefficient of thermal expansion is considerably higher for aluminium than it is for steel. In other words, aluminium dilates more. Much more.
 
I recently had a similar issue with a SS stud that had sheared on a windless casing. Before I took the pipe wrench to it and sheared it again almost flush with the casing I was considering hot/cold treatment. Heat with torch, cool with ice spray a few times and it should, I read, break the bond due to the different expansion rates of the metal.
In the end I filed it flush, punched, drilled and tapped a helicoil. Surprised how easy it was!
 
Zen Zero said:
Someone is bound to chirp up with WD40 is not a proper penetrating oil and brake fluid is corrosive; none of which is true.
Click to expand...

Most brake fluids are glycol-based, and strip paint very well, so are best kept away from any painted/coated parts of an outboard. I've never heard it said that they're corrosive; indeed, since they are hygroscopic they usually contain corrosion inhibitors. If spilt on painted parts it should be washed off with water, not wiped.

DOT 5 brake fluid is silicone-based, non-hygroscopic and does not strip paint. No idea of its effects, if any, on stuck studs.

If all else fails, spark-erosion is the best process for removing the OP's stud: he'd be glad the engine's portable.
 
alright lads, thanks for all your replys, im still unsure how to go about getting some penetrating fluid into this, i should have included a pic before to help, i've got one here now, do you think i could drill a hole horizontally through it and get some purchase that way?, i also think these studs are obsolete :eek: so if i wreck it i wont be able to replace it with an original oem part, i also went looking for a tool to grip this thread without damaging it.........never found one,closest i came was some long nosed mole grips,which would defeat the purpose really,on the flip side the fresh water its been soaking in looks to have softned the entry point of the stud,so perhaps i could scrape away a bit more to try and get in some fluid now, as you will notice in the pic the nut is still attached,this will not thread all the way off making things awkward to get into,see what you make of this pic.

View attachment 29355

Pete
 
If its a matter of removing a threaded stud just screw a new nut on the end and secure with a weld plus heat to the stud. In fact welding the nut on can often generate enough heat to help free things.
 
Penetrating oil?
Personally, I find heating the casting using either a hot air gun or a mini butane torch before sloshing on 3 in 1 oil or red diesel quite effective.
3 in 1 is very runny at 200degC.
You may need to limit the heat applied if there are rubber seals or plastic bits in the assembly, but even so, 100degC is reasonable.
 
Looking at the photo, you need the whole casting to slide down that stud?
I would do up the nut, then pack the space above it. Then undoing the nut against the packer will put a pressure on the casting to help pull it off.
Then heating the casting and jolting it with a block of wood will give you a fair chance of it shifting.
 
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