Corroded/Rusted Hardare

Need some advice on how to attack some adjustable seat hardware that is rusted in place.

Arrangement: Bolt (not stainless) > Washer (not stainless), Washer? (Plastic) > Nut (not stainless). Pictures below.

I’ve been attacking these pieces for 5 hours with various penetrants, screwdrivers, wrenches etc. The nut is seized to the bolt inside the cockpit and the bolt head to the washer. Three of these on each side. The middle of which is barely accessible, I don’t think I can get a cutter in there if I have to.

What’s next? Drill out the head of the bolts…but then how do I release the nut? Moving the seat gets me an extra few inches of leg space.

Could you grind off the head of the bolts?


Grind off or cut off with Fein / mulit-tool Penetration lubes may need a day or more to work in, even a week.

No head on bolt push bolt through. Lube them few times a day for a few days. I use to do scaffold jacks for week once a day little spritz of PB Blaster.

Patience patience of which I’m usually short on :laughing:

Small air tool with carborundum blade or grinding stone. Grind Philip heads off or cut them. Know a mechanic they will do it easy. Live near Long Island I’ll cut them off.

I would drill out the screw heads using a drill bit that’s just under the OD size of the threaded shank. The Phillips head on the screw will help center up the drill bit, and the head will usually just fall off once the drill gets down to the threaded part of the bolt. If the remaining part of the bolt doesn’t come out easily, you may need to tap on the cut end using a pin punch and hammer, or even just use a blunted 10 penny nail instead of a pin punch.

The entire bolt might decide to spin as you do the drilling. If so, you’ll need to grab the bolt on the inside with pliers using one hand, and drill with the other hand. Awkward but should be doable.

1 Like

If drilling head off start with small bit so it centers in Philip’s then increase drill size gradually. Or get a small cone shaped stone for a drill and grind head a bit to start good surface for a drill bit. Strap hull down in comfortable position so it can’t move while you are working on bolt head or nut.

The only grinder cutter I have is a Dremel. Not sure it will generate enough speed to cut through or if there’s enough space between bolt head and that washer. I’ll check.

I have a screw / bolt removal kit. If I understand correctly, drilling through the head of the bolt should make it fall away…correct? Haven’t done this with a nut on the other end.

I would avoid grinding, as it could generate enough heat to damage the boat. Drilling is the better way to go, but take your time for the same reason; you don’t want the bolt to get too hot.

1 Like

Great point. Also grinding could result in an errant cut into the gel coat

Grinding or drilling will make heat. Do each bolt in stages and cool with water spray.

Maybe easier if you don’t have the tools to take it somewhere and have them do it.

I’d soak it with penetrating oil, vise-grip the nut and put a impact driver on the screw head. (Lots of pressure) If all the driver does is round out the head then it’s ready for drilling out. Taping around the head may shield it from errant scrapes.

That’s where I stopped yesterday. I realized I was starting to round out the heads.

Ditto on drilling until the head comes off. I would use oil for coolant. Replace with stainless steel and a shorter bolt.


You have received a lot of good advice. Here is what I would do if I were you.

Go to harbor freight and buy a 4” angle grinder. They have one for 10 bucks that every bit as good as the $60 brand names. Get a pair of safety glasses for a buck and a pack of thin cutting discs for 5 bucks. You will wonder how you ever lived without the grinder.

I would start by grinding the straight blade slot deeper and get a big screw driver into the new slot with a wrench or vice grips on the nut as suggested. 9 out of 10 they will come off. If that doesn’t work you have washers under the head so you have something to protect the glass. Slice those heads right off and punch the bolts thru.

I wouldn’t worry about the heat but if you want to squirt some water that’s fine as well.

Drilling the screw heads out will also work. you would need a good quality drill bit as even the cheap screws are toughened up a little and a two flute drill bit bouncing around trying to get started in a Philips screw head isn’t always easy.

Depending on the screw you can sometimes get a bite on the head with vice grips as well. Might be worth a try.

Throw all the screws away when done and buy new stainless screws.

Definitely use a drill and several sized bits to drill the head off the screw and use cutting oil to lubricate and cool the drip bit.

And and what’s happening? We all await!

I went to work! That’s what happened.

I’m using the Norm Abram “measure twice cut once” strategy to make sure I don’t damage anything. Safest bet seems to be taping the area to present errant scratched and drilling the heads. A co-worker also suggested slicing through the nut if I can to loosen it from that side.

If that fails, I’ll have a go with the Dremel to slice the head off. Tomorrow looks nice for a paddle, so I’m not going to start something tonight and run the risk of having a half-mounted seat in the morning.

1 Like

There are many good suggestions here. I’ve seen and removed worse.

PB Blaster is great. Liberally spray the nut, shaft and bolt head, then wait at least an hour. Spray again. Check your bolt head. hard to tell from the photo, but it appears to accommodate a flat screwdriver, a Phillips or a square drive. If you can, use the square drive. It has better purchase and doesn’t torque out like a Phillips screwdriver will. use reasonable force to not round out the square. A well fitting impact driver and a longer handled 6 point box wrench or if it will fit in the space,a 6 point socket on the nut can often break the bond. Carefully twist the nut/bolt back and forth to break the bond and allow oil to penetrate, if possible. A 12 point wrench or a adjustable wrench may round off the nut. Vise grips and pliers tend to pinch the nut onto the shaft even tighter. They can work, but it takes more force. The 6 point box wrench or socket are best. same for an impact driver over a screwdriver. The idea is to get some vibration and movement to allow more penetrating oil into the nut/bolt interface. If you have the time, and the bolt hasn’t loosened, spray more PB Blaster and wait a day. Try again. Do this every day for up to a week.

If this hasn’t worked, you have choices. You can try to break off the nut by twisting it with sufficient force, then just back out the bolt. The danger is damaging the bolt head and/or nut making removal more difficult. You can try a nut breaker, a tool that encases the nut and breaks one side by tightening a screw with a wedge on the end. This relieves nut tension and allows the penetrating oil to enter all the threads. You can drill the bolt head; start with a small bit and progressively work up to larger bits. If you haven’t rounded off the nut, use the 6 point wrench or socket to keep the bolt from spinning. Go slow with the drill and use a little oil to keep the bit cool. Slow is smooth and smooth is fast. BTW, if you can cut off some of the excess bolt, it may be easier than trying to unscrew the nut the entire length of the corroded bolt. You can also grind off the bolt head or nut, if you have access to them and you’re careful. Often I see grinder’s slip and damage the part, so I prefer drilling. Good luck and let us know what worked or didn’t…


The easiest way is to drill the head off. Since it has a metal washer under the head you can also use a Dremel tool with a cutoff wheel and cut off the head flush with the washer. Work in stages so as not to overheat the bolt. You can even do this with a fine tooth hacksaw.

Then use a pin punch to drive the bolt through to the inside. Use 316 or marine grade stainless steel, especially if used in salt water. A stainless cap or acorn nut and the right length replacement bolt will eliminate a sharp bolt end inside the boat.

Tomorrow looks to be a miserable rainy day. Perfect for drilling and cutting!

1 Like