Stubborn belly pan bolts

Need some advice. Flat-head bolts, down flush in a countersink, about 19-21? mm, with a 14 mm allen socket. (Kobelco sk250). Need to drop at least half of the split pan to fix a track drive hydraulic leak. Have broken two 3\4"-1\2" drive adapters (one with a breaker and cheater and one with a 1'" burp gun). One of three bolts came out. Can't torch out an access hole because the pan has flammable hyd. fluid, hoses, and the usual mouse nests in it. And no other access to extinguish even a small fire. Torching, drilling, or grinding the heads off down in the c'sinks makes it extremely difficult to remove the remaining bolt portions. We heated the bolts up to "red" just before quitting tonight. Hopefully hot enough to release red loctite if that was used previously. If that doesn't do the trick, then WHAT NEXT?
I may be able to weld a large nut onto the flathead or cut the heads off and plan on welding the pan on at reassembly (not the best option, I know). Any good advice out there? At least it's on a clay pad with decent weather forecast tomorrow. It could be belly deep in mud, ice, and snow. Or worse!

Drill babby drill!

weld big nuts on and use a big breaker bar, the welding probably will heat them up good to give a little help to loosen..

I hate countersunk bolts. Those SOB's seize tighter than a bulls butt in a bug storm. A big hammer is the best tool if you have room to swing it. Ideal is to put a hex bit in the socket and use a hollow punch to shock the head without riveting the hex closed. Next best is to just hammer the hex into the socket.

What you really need is called an "Old Man" screw knocker. One end goes into your air hammer, the other has a 1/2" drive for a socket. There is a handle in the middle to turn the socket.

Maybe the boss will spring for a 3\4 Magdrill. (Not likely, but I can always dream can't I?)
I was hoping for "just grab some some 'Magic-Mystery Bolt Remover', apply liberally, wait five minutes, and watch the bolt spin itself out"!
I don't think the heads are seized to the plate though. The pan will move just a bit. C'sunk heads and corrosion (or red loctite) are a Bad combination. I'll see just how big a hammer I can swing under there And dig up some large nuts and 7018! Thanks!
If these come out, they'll probably be replaced with hex heads and washers. I doubt that losing 3\4" of ground clearance will cause much of a performance drop. LOL.

hillbillywrench said:

Maybe the boss will spring for a 3\4 Magdrill. (Not likely, but I can always dream can't I?)
I was hoping for "just grab some some 'Magic-Mystery Bolt Remover', apply liberally, wait five minutes, and watch the bolt spin itself out"!

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Its called hillbilly juice on the smart end of the hammer! Just messing around, sounds like a real job.

I would certainly spray it all down real good with penatrating oil and let that set. Hammers, heat and the rest next.

The 'smart' end of the hammer is the end you give to the ambitious young assistant. Maybe even loan him some vise-grips to hold the punch with. Not the new pair though!

The heating them and letting them cool will probably make most come out whether it's loktite or rust holding them

In a similar situation ... (Flat head countersunk) I welded the head to a piece of rebar. Using the rebar as a lever, each turned out easily. I think the heat and torque did the job. This might be easier than welding a nut upside down.

Don't forget to PRAY with each attempt. LOL

If you can get a good swing on a hammer, a hand impact driver is the best thing ever for allen heads. And Kroil the daylights out of them first.

I got them out! They wouldn't budge this morning, then tried hammering, no luck. Went digging and found a large jam nut (ID a little under the head OD, about 1\2" thick, and had a 46 mm socket that fit it). Welded a small bead around the allen hole in the bolt to keep the nut from sliding off location. One hand holding nut, one flipping down hood (no auto-darkening), and one...finding stinger, finding middle of nut then tacking it on. Wait, I was solo and only have 2 hands! Got it tacked somehow and then welded it securely. Rebar or Steel stock would have been easier, maybe. It still took a 3\4 breaker and long cheater and a grunt or two, but they started turning. Cut the nut off the removed bolt and used it on the second stuck one (only had one jam nut, lol).
One looked rusty, one looked like threadlock used. I think the heat from the welding (high heat, small area) is what helped the most. Now waiting on the metric hose to install and reassemble.
Thanks for all of the advice! But I'm glad no one saw my Happy Feet Dance when they were finally out! BTW, if I saw allen's on a regular basis then I think the hand impact and auto-dark hood would be on my shopping list.

I "think" welding with a high strength rod is the most help. Like welding beads on a bushing to shrink it. The cooling weld shrinks the fastener, breaking the bond.

I have run into some of those flathead allen socket bolts that just would not move. Then after just heating the head with a torch till it turned red then let cool and they would come out easy. The only thing then I noticed is very often the allen hole in the bolt is now very tight. Guess the head deforms some when hot then when it cools it shrinks down making the socket fit tight and the bolt get loose.

Got the kobelco going yesterday. Boss wanted to beat the rain. I put one bolt back in with the big nut still on it, cleaned up the other I had welded, and liberally applied never-seize to all three. Kinda like me, "ugly but effective"! (That's what my wife says, too.)
Thanks for all the advice!

hillbillywrench said:

Got the kobelco going yesterday. Boss wanted to beat the rain. I put one bolt back in with the big nut still on it, cleaned up the other I had welded, and liberally applied never-seize to all three. Kinda like me, "ugly but effective"! (That's what my wife says, too.)
Thanks for all the advice!

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Hope the boss will at least let you order new bolts so next time the Kobelco is in for service you can slip them in!

And in the word of Red Green: