Removing only 1 stubborn chain plate bolt in tight space for windvane mounting

[Sailor.Sax]

Hello!

I am attempting to fit a monitor vane to my Pacific seacraft Mariah 31. After a lengthy discussion with Scanmar about mounting location, we agreed that using one of the stern chain plate bolts would be best. Now actually getting the bolt out is turning out to be a real challenge. I have removed the nut on the inside, but do not have enough room to tap the end of it out with a hammer. it's a very tight space, would be lucky to have 2.5 inches from side to side. Does anybody have any solutions on how to best remove the bolt? Would the best solution be to just cut the head off with a grinder and punch it through from the outside? Also should I take tension off the chain plate by easing the backstay, or would the other 4 bolts be fine to hold it. All help is greatly appreciated. Thanks

[Calif.Ted]

I'd try a long pry bar, place on threaded end and hit it as close to that point as possible, it might back it out enough to get the bar under the head. Plan B, loosen backstay and all four nuts, pry up whole chainplate just enough to get under the bolt you want.

[BugzyCan]

The trick to getting bolts off motorcycles that have had red loctite applied is to heat the bolt, then apply wrench and stand on the wrench a while applying slow pressure, and you may need to jump on it a few times, but be ready when it breaks free, you will fall.
Another way is with an air impact wrench like they use to remove wheel bolts, but not sure if you have room for that.
I would try loosening it first before cutting anything off, if you can get it off without doing that the job will be a lot easier.

[JPA Cate]

Hi, Sailor.Sax,

So, if I understand you correctly, nothing is holding the bold in place at all, except the caulking that went in with the bolt? Try pulling it out with vice grip pliers, wiggling it like unwinding it from the caulk. If it didn't work that way, me, I'd try some weasel piss on it (equal parts of automatic transmission fluid and acetone). Jim has had super luck with it. You should be able to grab the bolt with vice grip pliers and pull that puppy out, after it has sat for a while. (A while = long enough to make and drink a cup of coffee.) It might take 2 cups of coffee, but usually the atf guides the acetone in, and out the object comes, with a little help. "Better living through chemistry."

Ann

[Minggat]

Originally Posted by JPA Cate

Hi, Sailor.Sax,

So, if I understand you correctly, nothing is holding the bold in place at all, except the caulking that went in with the bolt? Try pulling it out with vice grip pliers, wiggling it like unwinding it from the caulk. If it didn't work that way, me, I'd try some weasel piss on it (equal parts of automatic transmission fluid and acetone). Jim has had super luck with it. You should be able to grab the bolt with vice grip pliers and pull that puppy out, after it has sat for a while. (A while = long enough to make and drink a cup of coffee.) It might take 2 cups of coffee, but usually the atf guides the acetone in, and out the object comes, with a little help. "Better living through chemistry."

Ann

Thread drift alert.

The yard in Mexico set my new cutlass bearing in with 5200. I had no warning. Now with the boat in Hawaii, it's time for a new bearing. I know that there is a product that cuts 5200, but no experience with it. Hoping that 'weasel piss" will be smarter.

[Steve Bean]

Can you leave the bolt in place and weld another onto it to mount the vane? Drill another hole through the chain plate for another bolt? Push the bolt out from the inside with blocks of wood and wedges or levers or something like an improvised tiny screw jack? Partially remove another nut on the inside - if accessible - and use it as an anchor for prying to exert pressure on the bolt, after applying penetrating oil of your choice for a few days. Heat while pushing. Grind off bolt head and drive it in, unless it's a carriage bolt, which has a square under the head that would make it hard, and destructive, to drive.

[Wotname]

Originally Posted by JPA Cate

Hi, Sailor.Sax,

So, if I understand you correctly, nothing is holding the bold in place at all, except the caulking that went in with the bolt? Try pulling it out with vice grip pliers, wiggling it like unwinding it from the caulk. If it didn't work that way, me, I'd try some weasel piss on it (equal parts of automatic transmission fluid and acetone). Jim has had super luck with it. You should be able to grab the bolt with vice grip pliers and pull that puppy out, after it has sat for a while. (A while = long enough to make and drink a cup of coffee.) It might take 2 cups of coffee, but usually the atf guides the acetone in, and out the object comes, with a little help. "Better living through chemistry."

Ann

Ann, while it is a good idea if the bolt had a hex head, it looks like the bolts are cup headed - see the OP's second photo. There is not much to grip!

While grinding off the head might work, it might be a carriage bolt and grinding off the head isn't much help.

Me, I would bite the bullet and try to remove the entire chain plate without any grinding or welding.

[Uncle Bob]

Originally Posted by Wotname

Ann, while it is a good idea if the bolt had a hex head, it looks like the bolts are cup headed - see the OP's second photo. There is not much to grip!

While grinding off the head might work, it might be a carriage bolt and grinding off the head isn't much help.

Me, I would bite the bullet and try to remove the entire chain plate without any grinding or welding.

Ditto, remembering that as soon as the chainplate is released it needs to be resealed anyway.

[Dsanduril]

If you are willing to go the destructive route and have all the tools:

Use a center punch to start a hole in the head.
Drill out the hole to about 3mm(1/8”)
Tap the hole just a bit
Thread in something that you can now use to pull from the outside.

Not as simple as cutting off the head, but risk only to the bolt rather than to chainplate, etc.

Other option, if the can fit something in your 2.5” space is to try and jack it out. Even a small car scissor jack can work if you can fit it in the space. Pretty much anything that you can screw open to put pressure on the tip of the bolt.

[Dymaxion]

Remove the nut then put the flat face of the "straight" end of a crowbar against the bolt. Use a 2lb. Sledge hammer, a carpenters hammer is too light. Grip the crowbar in one hand at the curved end tightly and smack it hard as close to the flat end as possible. You'll get a good jolt in your gripping hand, the bolt will get about 10x that amount. 3-4 solid hits, keep the flat face of the crowbar as perpendicular as possible to the bolt as you don't the bolt to be bent sideways. If it hasn't let go by then check that you are not mushrooming the bolt, and quit if you are. No point making the bolt into a rivet!

If it won't budge find someone with an arc welder and weld a short length of threaded rod on the outside head. Using a suitably sized socket or short bit of pipe larger diameter than the bolt head, slip it over the threaded rod, put a few large washers on the rod and then a nut. Bit of grease or oil, then tighten down and it should pull out fine. Don't send the welder home until you've tightened it down and extracted the bolt, just in case the weld fails. Call backs cost more, and it's the welders responsibility to make a good weld in the first place. Welding heat will help soften adhesive too. Good luck.

[roverhi]

Originally Posted by Sailor.Sax

Hello!

I am attempting to fit a monitor vane to my Pacific seacraft Mariah 31. After a lengthy discussion with Scanmar about mounting location, we agreed that using one of the stern chain plate bolts would be best. Now actually getting the bolt out is turning out to be a real challenge. I have removed the nut on the inside, but do not have enough room to tap the end of it out with a hammer. it's a very tight space, would be lucky to have 2.5 inches from side to side. Does anybody have any solutions on how to best remove the bolt? Would the best solution be to just cut the head off with a grinder and punch it through from the outside? Also should I take tension off the chain plate by easing the backstay, or would the other 4 bolts be fine to hold it. All help is greatly appreciated. Thanks

Looks like you could pry it out with a flat pry bar. If there is too much space to apply pressure stuffing a piece of wood in to pry against might work. Heating the bolt with a heat gun might help to loosen the caulk. It's undoubtedly a carriage bolt so grinding the head off and punching it through is a non starter.

[Orion Jim]

Dymaxion beat me to it. Weld a piece of threaded rod to it and it will be simple to remove, get on with the install. Monitor was a great choice. I’m sure you will come to love yours.

[SVTatia]

• Get a 2" long 1/4" (or 3/8") flat head machine bolt and one nut.
• Find a piece of pipe or someting that you can put the bolt inside and slighlty longer than the bolt.
• PLace one nut right next to the head, then the pipe.
• Place the end of pipe against the hull shimmed with some thin metal to provent the pipe from going thru the glass.
• The head of the bolt should go against the bolt you are trying to remove.
• Start torquing (removing) the the nut close to the head with a wrench, which will push the pipe against the hull and bolt you want to remove out.
• Once you have some of the bolt out the other side, remove it with a vise grip, hammer and some prayer, but do not curse, or it will not work.
• The challenge is to find the pipe to fit outside of the 1/4" (or 3/8") bolt and keep it against the hull. If you cannot find the pipe or similiar bushing, a bunch of nuts larger than the bolt will do, kept together with marine grade duct tape...
• Patience! and easier done than said.

[jakkum]

But....yes, I would first take the backstay away, use something else to gold the mast, and slacken all the other volts af the chainplate.
Then try any of the other good ideas.

[slug]

Put a shim behind the bolt and against the bulkhead

Loosen the nut until it butts up against the shim

The nut will push the bolt out