Broken Bolts on engine

[frogpond]

I need a little advice on how to solve this problem, two 1/4" bolts are snapped off on intake manifold and another one on the cooling manifold. I tried easy/out but that didn't work so now tapping 1/4-20 in center of 5/16 bolt. need to know how deep I can go using bottom tap how long are original bolts? and is this a through holes or does it have bottom in casting? i could go with Heli-coil but need more info . If I try to get out other bolts I'm sure there going to break I believe I'll have better luck if I let engine get running for awhile I'm not at that point yet, but close, maybe week out, but now on 10 hr. days at work so limited on time. Regards, Paul

[Skagit Hideaway]

I need a little advice on how to solve this problem, two 1/4" bolts are snapped off on intake manifold and another one on the cooling manifold. I tried easy/out but that didn't work so now tapping 1/4-20 in center of 5/16 bolt. need to know how deep I can go using bottom tap how long are original bolts? and is this a through holes or does it have bottom in casting? . If I try to get out other bolts I'm sure there going to break I believe I'll have better luck if I let engine get running for awhile I'm not at that point yet but close maybe week out but now on 10 hr. days at work so limited on time. Regards, Paul

For the remaining bolts - soak with WD40 for a while, then, without using too much force, try to rock the bolts back and forth (loosen/tighten) until they move just a small fraction of a turn. Continue until the WD40 gets worked deep into the threads. Once they break free, you will be able to turn them further and further. Don't try to remove them all at once as they will bind again. Eventually, they will come out.

For the broken ones, once the flange is removed you can TIG weld a stud onto whatever is left sticking out. Then proceed as per above.

[Super Sportster]

need to know how deep I can go using bottom tap how long are original bolts? and is this a through holes or does it have bottom in casting? i could go with Heli-coil but need more info . If I try to get out other bolts I'm sure there going to break I believe I'll have better luck if I let engine get running for awhile I'm not at that point yet, but close, maybe week out, but now on 10 hr. days at work so limited on time. Regards, Paul

Paul I can answer the length question and blind or through hole question by the weekend when I have time to dig out some disassembled parts. I've had the manifold plate off for gasket replacement several yrs ago but don't remember much about it. I do know the thermostat bolts always break, those I've had to drill and heli-coil.

[Skagit Hideaway]

Torquing the frozen bolt back and forth works every time, even in the most stubborn cases. With each application of force, the bolt shaft flexes enough to break a small portion of the corroded section free, from the top, down. You just have to torque it back and forth, until you work through the entire corroded section. Then you will feel the bolt turn, ever so slightly. Continue torquing in both directions and adding WD40 until you can unscrew it completely. The aluminum threads will be in good enough shape to reuse. No need to bore out and install a thread insert.

You can weld onto the broken stud without damaging the aluminum block in the least, even if it is broken off flush with the mating surface. In that case you cut the head off a spare bolt and drill a hole through the center of it, slightly larger than the bolt shaft diameter. Place the donut over the broken stud and weld through the hole.

[Super Sportster]

Paul I can answer the length question and blind or through hole question by the weekend when I have time to dig out some disassembled parts. I've had the manifold plate off for gasket replacement several yrs ago but don't remember much about it. I do know the thermostat bolts always break, those I've had to drill and heli-coil.

Pulled a manifold today, thermo and manifold bolt holes are blind holes. The depth of the thermo bolt hole is 1/2", the manifold bolt itself that I took out is 3/4" in length. The depth of the threaded hole is .719", damn close to 3/4"

[John Nelson]

This is why you can buy a used 15000 dollar motor for 350 bucks. You might still use the easy out with an acetylene torch heating the cast to nearly liquid. Hold the torch on it while turning. If that dosnt work you can drill through the bolt with the largest drill that wont damage the threads in the cast. 1/4 for 5/16 3/16 for 1/4. Centering is the issue. Then take your dremmel tool and grind away the bolt from the inside till you hit the threads in the cast, then pick out the threads of the bolt and clean up with a bottoming tap.

[John Nelson]

I wouldn't try to take apart an outboard without an acetylene torch. Ive had luck countersinking nuts , welding them on broken bolts and turning them out with a torch. Cutting the heads off bolts removing cover to get acess with a torch and backing them out with vise grips. and cutting heads off bolts and welding studs on whats left when I know there is no hope. Ive had several motors that could not be saved. I used to tell people who just got a new motor to antiseize anything they expected to take apart of course that was nothing.

[Helmar]

I wouldn't try to take apart an outboard without an acetylene torch. Ive had luck countersinking nuts , welding them on broken bolts and turning them out with a torch. Cutting the heads off bolts removing cover to get acess with a torch and backing them out with vise grips. and cutting heads off bolts and welding studs on whats left when I know there is no hope. Ive had several motors that could not be saved. I used to tell people who just got a new motor to antiseize anything they expected to take apart of course that was nothing.

Hey John..
I myself have and use the hell out of my acetylene torch. I would some times Drill a hole in the broken stud, then heat it up, hit it with a wet rag. Then put in one of the better easyouts. I used to have to do this to the old 352 and 390 ford motor blocks as they were famous for breaking off when trying to remove them.

In tight places, I have use the stick welding rod for gas welding and welded it to a nut, then held that up on a broken stud of a exhaust manifold. Then used the 1718 welding rod and welded it to the broken stud. Heat the area around it, cool the stud, heat the area around it, cool the stud and was able to remove them that way too.

Nevertheless, none of its easy....I have also drilled some a tad crooked as the bit would drift a tad, even with a Big Center punch hole. Once the stud was out, I ended up having to drill it out bigger for a heli coil and once that went in, I used JB Weld and ran the bottom tap in and out a few times.

I also have a Large bottle of Antiseize that I use too

Good luck with it Paul. It will come out.

[Super Sportster]

Those thermostat bolts are a tough one, with 1/2" of thread, about another 1" in bolt length and the small diameter almost everyone of those twist off that I have attempted to remove. Drilling them out has to be spot on as it's a bear with a steel bolt into an aluminum casting. I've been pretty good at this lately with a transfer punch and really paying attention to positioning the drill straight. As others have mentioned welding a nut on sometimes works, after the weld, I have learned to let everything cool completely before trying to remove the bolt when working with aluminum castings and steel bolts.

FYI, another problem bolt are the two center manifold bolts. These seem to come out about half the time without breaking!

[Skagit Hideaway]

Those thermostat bolts are a tough one, with 1/2" of thread, about another 1" in bolt length and the small diameter almost everyone of those twist off that I have attempted to remove.

It's often the first attempt to remove the bolt that stresses the shaft so much the bolt ends up breaking. If I suspect it is frozen, I rock it from the start. Key to not twisting it off of course is to never apply more torque or range of motion than the shaft's temper can tolerate. You must have a feel for the difference between the force needed to free the head from it's tension against the aluminum, what force/amount of head rotation exceeds the shaft's springiness, and most importantly, the concentration and patience to maintain that awareness. As soon as you loose it, the shaft is sure to start shearing in two. It is a Zen meditation and there's nothing quite as deeply rewarding as removing seemingly impossible bolts with just the gentile force of your hands.

[frogpond]

Thanks for all the input I'm pretty sure we helped a lot of people with similar problems heat wasn't a option for me being that I didn't want to take apart these particular components right now. I know what you mean the breaking point held it at tension back and forth tapping the end of a broken portion I've read this sets up a vibration that can aid in process. The 10-24 bolt on the thermostat housing, it eventually broke, center drilled and re-tapped for fix. I think if I felt I had enough time to play with it might have finally give in I let it soak with Kroil several days. Regards, Paul "Pray for Rain"

[Helmar]

Thanks for all the input I'm pretty sure we helped a lot of people with similar problems heat wasn't a option for me being that I didn't want to take apart these particular components right now. I know what you mean the breaking point held it at tension back and forth tapping the end of a broken portion I've read this sets up a vibration that can aid in process. The 10-24 bolt on the thermostat housing, it eventually broke, center drilled and re-tapped for fix. I think if I felt I had enough time to play with it might have finally give in I let it soak with Kroil several days. Regards, Paul "Pray for Rain"

I know those can be hard to remove.
Several things I have done that might not have been mentioned.
I do have a cutting torch and gas welding tip for it and have heated up the Bolts, let them cool, heat it up again, let it cool (this is a tool that I would be lost without). Then take a flat punch and wacked the end of the bolts while drowning them with a "real" penetrating liquid, something other than a WD40 product.
If I was able to get right on the end of the bolt with a hammer, the better. Then starting out trying to work it back and forth.
I also have a air chisel that I put the flat nose in and pound on them with that.

Like for tie rod ends. I have a pickle fork tool but that always destroys the tie rod boots but loosing the bolt and whacking it with the air tool or hammer, they drop right out.
I think the biggest part to doing those is having patience.