Stuck muffler screw

Jus climb into he Wayback Machine and apply antiseize to the screw before it goes in. JR Dweller in the cellar

stryped wrote:

You could hit the store and get a hammer-type (manual) impact driver.

You can get out a fairly well buggered phillips-head with one of these since the bit is driven into the screw quite strongly.

Dave

If heat and visegrips won't budge it, a bolt-extractor won't either. If (when) the hard bolt extractor breaks off in the bolt, you then have a real problem.

My approaches would be:

1) drill a hole in a bit of metal, place that over the screw head, weld it quickly with TIG, MIG or stick. That'll go so fast it won't have time to harmfully heat up the cylinder. Then tap on the new "handle" until it either comes out or breaks off. This often works, partly because the short-duration intense heat on the bolt tends to break corrosion and loosen it. 2) If (1) is impractical or doesn't work: drill out the bolt, re-tap the hole. If you miss the center you may need to drill oversize and shoot in a helicoil.

I definitely would not screw around with a bolt extractor, particularly one from HF.

If there is access use a dremel to cut a slot, then use an impact driver.

You might get away with an impact driver phillips (if you have not yet tried one) if the head is not too badly damaged.

I have found the the best way to use an impact driver is to carefully seat the bit, carefully take up the rotational slack, and carefully hit it REALLY REALLY HARD with a BIG hammer ("carefully" in the third step meaning hit the end of the tool instead of my thumb).

If that does not work then if the screw is holding something on that has some thickness, grind the head off flush with the something, then remove the something, then go after the stump with your vicegrips.

Use some grease on the threads of the new screw.

Don I have used this method many times with good success. I first tried it in desperation on a broken aluminum water pump mounting bolt. I used to have a collection of stuck fasteners in my toolbox that that I had won the battle with. Steve

Use an impact screwdriver as mentioned above. It can be embarrassing how easily stuck screws come out with one...

Mark Rand RTFM

I'd be inclined to try the impact driver first as others have mentioned. The muffler fitting I have seen on small engines that use a bolt fitment has the bolt going through the muffler so until you remove the muffler you can't get the heat to where the thread enters the block, heating the screw head alone is likely to sod all good as it's too far away from the block. If the screw head can be ground off and the muffler removed then careful heating of the screw adjacent to the block may get enough heat in there to help loosen it, that and and you can get some penetrating oil at the thread. Alternating heating and application of the penetrating oil should help free it if heat alone doesn't.

"David Billington" wrote: (clip) If the screw head can be ground off and the muffler removed then

^^^^^^^^^^^^^^^^^^^ If you can grind the head off. that may release enough tension on the bolt to let you turn it with vise grips.

The last resort method I have used, which generally works is:

Drill carefully into the center of the bolt. Correct centering errors by leaning the pistol drill as necessary. Start with a small drill bit, and then increase the size in steps. You will reach a diameter where there is very slight contact between the drill and the ID of the threaded hole. At this point you can probably pull it out like a spring with a pair of needle nose, or clean it out with a tap. If your drilled hole is slightly off center, then pulling it out like a spring won't happen, but you may be able to pick it out or tap it out.

This does not require any heat.

Pop the head off the bolt and remove the muffler - then heat the bolt where it goes into the block, tap the enfd of the cut-off bolt with a light hammer, quench the bolt, and spray a GOOD penetrant like Kroil or "MouseMilk" on it. Heat it again and twist it out with a stud extractor or vice-grips.

Can I weld a nut on the head?

As a last-ditch method, I'm with you on drilling them out. I've broken off a few exhaust-manifold and muffler-clamp bolts with my hammer-driven impact driver. And those bolts are usually mush after a few years of cycling in all that heat. I've wound up drilling out a couple of them, on a Honda motorcycle and on a Volkswagen, with the method you describe.

-- Ed Huntress

I've done the drilling out on various occasions and it works well especially if the drill is kept central. I wonder in this circumstance though, if when the tension is released on the screw, whether the screw will come straight out as it is in a hot area it may not corrode.

One time I was helping a mate change a cam belt and we could not undo a socket cap screw holding the tensioner in place as the socket was damaged. No matter what we did to try and keep the drive bit in the hex it was ejected when we applied torque. In the end we gave up for the evening and went down the pub for some beers. The next morning I removed the head of the cap screw with a carbide burr and that did the trick, the remains of the screw in the block could be undone with my fingers as it was not seized and showed no signs of corrosion.

Leo Sez:

"Drill carefully into the center of the bolt. Correct centering errors by leaning the pistol drill as necessary. . . . . ."

Good solution, I'm sure. But the OP didn't say if he had clearance over the bolt in which to run a drill. In that case, fall back on Don's suggestion to weld on a piece of metal for a wrench to get hold of.

Bob Swinney

"David Billington" wrote: (clip) If the screw head can be ground off and the muffler removed then

^^^^^^^^^^^^^^^^^^^ If you can grind the head off. that may release enough tension on the bolt to let you turn it with vise grips.

The last resort method I have used, which generally works is:

Start with a small drill bit, and then increase the size in steps. You will reach a diameter where there is very slight contact between the drill and the ID of the threaded hole. At this point you can probably pull it out like a spring with a pair of needle nose, or clean it out with a tap. If your drilled hole is slightly off center, then pulling it out like a spring won't happen, but you may be able to pick it out or tap it out.

This does not require any heat.

When i do this, I use left handed drills. nearly always, the drill catches and screws the fastener right out.

Karl

You certainly have my permission. Whether or not you actually CAN is another issue. I would grind and brush the screw head shiny and clean out the nut with a tap, or better drill out the threads to get a clean metal surface.

MIG works, I use it to fill up drilled out spot welds, but try it on a different nut and bolt first to convince yourself you can fill the hole with solid steel instead of flux, since you can't see the puddle. An easy-running arc rod like 7014 might work well for you too. I tried both to weld drilled retainer plates onto the ends of pivot pins for my bucket loader, then found TIG to be best, mostly because it annealed the drill rod pin further and didn't leave a brittle area.

Jim Wilkins

Hammer impact driver. Worked well on the old Kawasaki motorcycle motor when the case screws corroded in.

Sure, but Clare's approach might be better. I somehow overlooked that it was a muffler screw.

Can you grind the head off the screw and then remove the muffler?

Wes

I've used the method MANY times in the last 40-some years and it USUALLY works.