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I recently acquired a free Toro Timemaster 30 inch with a Briggs 121S17-0127-F1 and I'm attempting to get it running. It had a blown head gasket, and in taking off the cylinder head one of the muffler bolts snapped. I've tried everything to get it out and I'm just about out of ideas. Here's what I've tried.

An entire bottle of pb blaster (not literally but a ton)

Filing down flat edges on the stub and rocking vice grips back and forth on it. Just mushed the metal right off the bolt.

Drilling out the bolt and hammering a torx bit in the opening. I've seen folks do this with great success. My torx bit snapped off in the bolt.

Grinding head on a Dremel to grind out the torx bit inside the bolt. Just melted the bit.

Next idea would be to grind a slit in the bolt and flathead it out, or try and tackweld a flathead to the top of the bolt and rock it out.

1. Any ideas or suggestions?

2. Do I actually need two bolts on a muffler?

3. Are there replacement mufflers I could use?

Really trying to avoid the $100 to buy a new cylinder head but also don't want to spend $$$ only to have to turn around and buy the head anyway.

Sounds buggared up pretty good by now. I would drill it out.

yes it will need drilling out but most HHS bits will only dull attempting it. Get yourself one those carbide tip concrete drill bit and drill out the remaining bolt. Then either tap it if possible or drill out for a Heli coil, tap it, and install a Heli coil.

There bolts are usually heat seized and heat harden. Carbide bits are the only thing I found to work reliably for removal.once the bolt is broken off. I even broke extractor off trying to remove these bolts and carbide is the only thing that will cut the extractor out.

I use good cobalt drills from tool supply house. Not the harbor freight ones.

Now now Hammer you HFT got the best bits. Even those I got years ago from Lowes were junk. Currently using Fastenal bits here for most of my drill along the Drill Dctor for resharpening. Just drill out 18 broken tri lobe screw and only broke one bit.

I have a couple indexes of the HF twist drills. I consider them as consumables. I have a drill doctor 750x and good to go with the HF twist drills to be used and abused. I have some good left hand twist drills and some good regular twist drills i reserve for precision work with the drill press. I have to sharpen the HF twist drills before i use them so i don't get the 3 sided holes.

If he snapped off a muffler bolt it is seized in the head it won't twist out with a left hand drill. Been there done that, many times.

My choice for quality.
Use reversible drill with left hand drill bits. Start small going slow with light pressure on drill & oil bit frequently to keep it cool.
Let us know how it goes, thanks, Mark

There is an engineering workshop down the road with a water jet drill
$ 20 and job done in 5 minutes, all that is left is the spiral of thread of the old stud / bolt
Now if I had a lazy $ 30,000 ?
If we have em down here in the bannana republic they must be on every street corner in the USA .
We spent around 100 hours removing a broken head stud in an Inter 445, only to find the machine shop could have come out with their mobile kit and removed in for $ 90 in 15 minutes.

You can't do it on an aluminum head but in cast iron i can use an oxy torch to blow a broken stud out of a blind hole and leave the threads intact.

MIG weld a nut on top of the broken stud. Remove with a simple socket and ratchet.

GENTLY rock the stud L and R and remove in SMALL stepped movements. Spray with PB if you like making a mess. Never seems to make it down inside the threads. Look at yours when you get it out. It will be bone dry.

slomo

bertsmobile1 said:

There is an engineering workshop down the road with a water jet drill
$ 20 and job done in 5 minutes, all that is left is the spiral of thread of the old stud / bolt
Now if I had a lazy $ 30,000 ?
If we have em down here in the bannana republic they must be on every street corner in the USA .
We spent around 100 hours removing a broken head stud in an Inter 445, only to find the machine shop could have come out with their mobile kit and removed in for $ 90 in 15 minutes.

Click to expand...

I wouldn't bet on it. Here nearly every automobile engine machine shop has closed up shop. Last one I knew of was over 100 miles away and I think they are closed now too.

Hammermechanicman said:

I have a couple indexes of the HF twist drills. I consider them as consumables. I have a drill doctor 750x and good to go with the HF twist drills to be used and abused. I have some good left hand twist drills and some good regular twist drills i reserve for precision work with the drill press. I have to sharpen the HF twist drills before i use them so i don't get the 3 sided holes.

Click to expand...

Have you gotten the LH guide for the Drill Doctor yet. I went ahead and one for my 750 here even through I have yet to get any LH bits.

The problem I had with the Lowe's bit was I couldn't even drill a hole the thickness of a bed rail (angle iron) without dull the bits.

Question through. Which style of point are you sharpening to and what angles to prevent the three sided starter holes. Here I usually sharpen and split the points on my bits to prevent walking and drill at around 300 rpm or less.

Don't have the left hand chuck. I only use the left hand bits on broken bolts i feel will twist out so they don't get abused. Most bits are sharpened at 118* but i use a little more aggressive relief angle than stock. I don't split the points if i am going to use it in the drill press. I have found most of the cheap asian drills have uneven flutes so you get the 3 sided holes. I have a bag of small drills a machinist gave me. Most of them are Cleveland brand. Night and day compared to the HF and box store stuff. If i want an oversized hole i just use a HF drill out of the box. They always drill slightly oversized holes. If the flutes are not exactly equal length you get the 3 sided holes.

I had a chain saw that I was getting to run and found that the muffler was loose so took out the first bolt but when I went to the second sure enough the bolt was very tight and I heard the dreaded snap. I was a bit lucky because there was a 1/4in still sticking up but even using a bit of heat didn't work to free it up. Thinking of how to get this done I remembered the the guys were I was working at used KANO AeroKroil for frozen parts so went to Ace and bought a can 10oz was around $ 15.00. Sprayed the bolt let it set for about an hour still tight hit it with a little heat resprayed and let it set over nite next day used a vice grip and rocked it back and forth and slowly it came loose and out it came. When I got the frozen piece out there was some of the oil in the bottom of the hole I was impressed and saved my butt. This stuff is expensive but it seems to really work well. I see the OP never got back so don't know if they ever got the bolt out or not.

OldDiyer said:

I had a chain saw that I was getting to run and found that the muffler was loose so took out the first bolt but when I went to the second sure enough the bolt was very tight and I heard the dreaded snap. I was a bit lucky because there was a 1/4in still sticking up but even using a bit of heat didn't work to free it up. Thinking of how to get this done I remembered the the guys were I was working at used KANO AeroKroil for frozen parts so went to Ace and bought a can 10oz was around $ 15.00. Sprayed the bolt let it set for about an hour still tight hit it with a little heat resprayed and let it set over nite next day used a vice grip and rocked it back and forth and slowly it came loose and out it came. When I got the frozen piece out there was some of the oil in the bottom of the hole I was impressed and saved my butt. This stuff is expensive but it seems to really work well. I see the OP never got back so don't know if they ever got the bolt out or not.

Click to expand...

I haven't retrieved the bolt yet. I ground it flush with the exhaust metal because there was no material left to vice grip

css9343 said:

I haven't retrieved the bolt yet. I ground it flush with the exhaust metal because there was no material left to vice grip

Click to expand...

Oh man, good luck with it now. Could of welded a nut on and removed it.

slomo

Anyone ever try one of these to knock loose a snapped exhaust bolt???

Cut a slot for the "screwdriver". Pounding it can knock the bolt loose???

I have one. Back when i had a Japanese bike it was a must for the JIS case screws. Used it a couple times on the big JIS screw on some Japanese car brake rotors. Be careful the cheap bits. Had one shatter and stick a piece in my arm once. All the cross slot fasteners on aisian vehicles are JIS not Phillips. Most cross slot headed bolts are also JIS and not Phillips. There is a difference

upupandaway said:

Anyone ever try one of these to knock loose a snapped exhaust bolt???

TEKTON 3/8 in. Drive Impact Screwdriver Set (7-Piece) 2905 - The Home Depot

Loosen corroded brake caliper screws, rusted body panel fasteners or frozen bolts with ease using the TEKTON 3/8 in. Drive Reversible Manual Impact Driver Set. This unique tool converts a hammer strike

www.homedepot.com

Cut a slot for the "screwdriver". Pounding it can knock the bolt loose???

Click to expand...

That will only work on grade 8 or higher bolts &/or bolts that are 5/16" or bigger in diameter as the bit will just shear the sides off the slot
Muffler bolts are one of the worst for corroding solid in the block .

Once removed, don't forget the

StarTech said:

yes it will need drilling out but most HHS bits will only dull attempting it. Get yourself one those carbide tip concrete drill bit and drill out the remaining bolt. Then either tap it if possible or drill out for a Heli coil, tTried ap it, and install a Heli coil.

There bolts are usually heat seized and heat harden. Carbide bits are the only thing I found to work reliably for removal.once the bolt is broken off. I even broke extractor off trying to remove these bolts and carbide is the only thing that will cut the extractor out.

Click to expand...

Tried that on a bolt I was trying to remove yesterday. This thing ate two concrete drill bits, three carbide burrs, and two diamond burrs($73) in under 5 minutes. Finally removed with a Hi-molybdenum drill bit after about 4 sharpenings. The chips looked like grey iron powder.

ILENGINE said:

Tried that on a bolt I was trying to remove yesterday. This thing ate two concrete drill bits, three carbide burrs, and two diamond burrs($73) in under 5 minutes. Finally removed with a Hi-molybdenum drill bit after about 4 sharpenings. The chips looked like grey iron powder.

Click to expand...

Masonary bits should never be used on metals unless the cutting tips are reground to saw tooth profile with the cutting edge leading.
BAck in the bad old days I used to reshape old masonary drills to cut HSS & work hardening steels like digging teeth & plow blades.
Down side is when the tip breaks through the cutting edge chips
Now days there is a plethora of various carbide tipped drill bits
What I have found works best is an end mill but you must grind the end of the bolt dead flat before you start using it.
And of course tilt the drill slightly and $ 20 goes snap .

I picked up a couple carbide drills thinking they would be good for drilling out broken studs. Nope. They just break easily. I went back to good quality cobalt drills.


I wish LOL

ILENGINE said:

Tried that on a bolt I was trying to remove yesterday. This thing ate two concrete drill bits, three carbide burrs, and two diamond burrs($73) in under 5 minutes. Finally removed with a Hi-molybdenum drill bit after about 4 sharpenings. The chips looked like grey iron powder.

Click to expand...

Strange I have been using the same single cut carbide rotary file since 2006. I have yet to find anything that it will not cut. Except it like to try to clog up with aluminum but it is not design to file aluminum, It take a different version for doing aluminum.

And my drill bits usually produce long curly q's, Some are long enough that I have to stop and break them off. Now the rotary file is usually produce fine filings. Those long curly q's does make clean up a lot easier. Those filings from the carbide rotary file causes me to need to dig them out of my fingers and usually requires a magnet to clean them up.

What I have found however is that most bits are rated under 1500 max rpm speed and many hand held drills are faster than the bits rated max speed. This is why most of my electric drill here are variable speed ones. I even have my drill press set at 250 rpm which it lowest speed I can set it at.

Most metals going slow it the key but there are a few where high speed is needed.

Hammermechanicman said:

I picked up a couple carbide drills thinking they would be good for drilling out broken studs. Nope. They just break easily. I went back to good quality cobalt drills.

Click to expand...

And yes solid Carbide drill bits are brittle as heck. They are not meant for hand drills at all and really not for drill presses either.

bertsmobile1 said:

Masonary bits should never be used on metals unless the cutting tips are reground to saw tooth profile with the cutting edge leading.
BAck in the bad old days I used to reshape old masonary drills to cut HSS & work hardening steels like digging teeth & plow blades.
Down side is when the tip breaks through the cutting edge chips
Now days there is a plethora of various carbide tipped drill bits
What I have found works best is an end mill but you must grind the end of the bolt dead flat before you start using it.
And of course tilt the drill slightly and $ 20 goes snap .

Click to expand...

The carbide bits also had a steel rating not just for concrete, masonry. The carbide would look like you had chucked it in a drill and while spinning ground it against a wheel, rounded edge.. And any sort of lube turned the powder into valve grinding paste.

I have considered getting some end mill burrs. I think the issue I was having was the material was hard May of been grade 12.9 from what I gathered from other sources. But due to the powdering effect had a clogging effect on burrs.

Ahhh, Those hard metrics are a pain to get out. I haven't tried anything above 10.9.

@StarTech Got a new set of stump grinder teeth for my nephews stump grinder a few years ago, and one of the teeth had a burr in the threads. Grabbed a new 5/8 tap and proceeded to run it through the threads. That tooth cut new threads on the tap.

This is what i use for all broken muffler studs ?

"An entire bottle of pb blaster (not literally but a ton)"

OK, so you quite literally used a ton of PB Blaster, I hope you let it soak in for a day or two. The oxy-torch method is your best best. Good luck.
If you go the route of cutting a slot and using a straight screwdriver, I recommend buying or borrowing a hammer screwdriver and accept that you will only get one or two tries.

Sounds like you've tried just about everything. I think that if there was enough stud sticking out to weld a nut on it you would have already tried that. Even then, you will still have the original problem of the stuck threads. I think that the only option you have now, if you are doing this at home, is to drill it out. Grind it down flush with the surface. This leaves a clean circle such that you can easily determine the center point of the stud. Take a center punch and lightly tap it to make a divot in the center of the stud. Once you are comfortable with the location of the divot, strike it harder to make it larger. Next, take a drill bit that is almost the same size as the base diameter of the stud and drill straight thru. If you have a really good drill press you can place the block in a vise and drill it straight. My drill press wobbles so badly that I could do a better job free handed. It is helpful to brace the block someway, perhaps bolt it down. The objective is to drill out almost everything but the threads while trying not to damage the threads in the aluminum (I assume it is aluminum). Once you have drilled thru the stud, take a pick and start working out the threads. If you are lucky, once you have drilled out the center the outer threads will relax enough to start turning. If it is an aluminum block, the threads won't be bonded to the aluminum and should come out freely. If the block is cast iron you will have a more difficult time with it. If you damage the threads slightly with the drill bit it will not be a problem. However, if you get off center and damage them badly you may have to go the heli-coil route to fix it. If you still have good threads 80% of the way around the hole it will still work. Nothing is going to leak out. One good stud and one questionable stud is better than just one good stud. You asked if you need two bolts. I think you do, but the motor will run with a leaky muffler or no muffler at all. Some motor blocks have the two threaded holes for a flange plus have pipe threads in the hole for a screw in muffler. Or if the hole is round you might be able to thread the inside with a pipe tap and buy a screw in muffler. HF has the large pipe taps. I bought a set. Good luck with it.

css9343 said:

I recently acquired a free Toro Timemaster 30 inch with a Briggs 121S17-0127-F1 and I'm attempting to get it running. It had a blown head gasket, and in taking off the cylinder head one of the muffler bolts snapped. I've tried everything to get it out and I'm just about out of ideas. Here's what I've tried.

An entire bottle of pb blaster (not literally but a ton)

Filing down flat edges on the stub and rocking vice grips back and forth on it. Just mushed the metal right off the bolt.

Drilling out the bolt and hammering a torx bit in the opening. I've seen folks do this with great success. My torx bit snapped off in the bolt.

Grinding head on a Dremel to grind out the torx bit inside the bolt. Just melted the bit.

Next idea would be to grind a slit in the bolt and flathead it out, or try and tackweld a flathead to the top of the bolt and rock it out.

1. Any ideas or suggestions?

2. Do I actually need two bolts on a muffler?

3. Are there replacement mufflers I could use?

Really trying to avoid the $100 to buy a new cylinder head but also don't want to spend $$$ only to have to turn around and buy the head anyway.

Click to expand...

You will most likely be unable to drill out the bolt if you broke a Torx bit off inside the hole you drilled....Torx bits are as hard or harder than a drill bit. Good luck.

My suggestion requires an Mig Welder or a Acetylene torch. Take a nut big enough to slip over the broken bolt/stud and weld the nut to the stud. The heat will break the stud loose and the welded nut can be used to back it out. Done this enough on cast iron blocks but not sure how the aluminum will react to that much heat.

Get an oxy-acetylene torch and heat it red hot and let it cool. I have seen bolts like that that can be removed by fingers after that being done.

"Cherry red" steel is generally accepted to be somewhere around 1200*F and 1500*F. Aluminum melts around 1200*F. "Dull red" is still around 1000*F. Not sure how that will work out with a torch

If there is a harden stud extractor or tap broke into the bolt you need a quality carbide grinder tip you can use in a Dermal type tool (rotary tool).
Harbor Freight has junk for this.
Taking your time, the broke parts can be removed without any lube by grinding it out.
Once that stuff is removed you can now ,using the same carbide, grind out the bolt till the wall of the bolt is very thin.
Now you can use a quality HSS drill bit to drill over size for a Heli coil.
Have taken many broke bolts and/or studs like this.
You have electrolysis between the steel bolt and the aluminum head.
Heat will work with steel on steel, not this.
Good luck.

Reading the last part of your post, I would first check if the head is warped, since it blew a head gasket. Second is find a friend who has a drill press (or buy one) and drill out the the bit and bolt with a cobalt bit.

css9343 said:

I recently acquired a free Toro Timemaster 30 inch with a Briggs 121S17-0127-F1 and I'm attempting to get it running. It had a blown head gasket, and in taking off the cylinder head one of the muffler bolts snapped. I've tried everything to get it out and I'm just about out of ideas. Here's what I've tried.

An entire bottle of pb blaster (not literally but a ton)

Filing down flat edges on the stub and rocking vice grips back and forth on it. Just mushed the metal right off the bolt.

Drilling out the bolt and hammering a torx bit in the opening. I've seen folks do this with great success. My torx bit snapped off in the bolt.

Grinding head on a Dremel to grind out the torx bit inside the bolt. Just melted the bit.

Next idea would be to grind a slit in the bolt and flathead it out, or try and tackweld a flathead to the top of the bolt and rock it out.

1. Any ideas or suggestions?

2. Do I actually need two bolts on a muffler?

3. Are there replacement mufflers I could use?

Really trying to avoid the $100 to buy a new cylinder head but also don't want to spend $$$ only to have to turn around and buy the head anyway.

Click to expand...

If you have a torch try heating it up before removing.Sometimes heat will do the trick if all else fails.

GOOD advice! It's wise to use this anti-seize on anything you may ever want to take back apart,no matter what that may be.

You have a big mess there. Try the sharp punch to break up the Torx bit. Washer and nut and MIG weld stud to washer and 1/2" nut. Heat the head in the area and give it a try. Check the head for flat, if warped find a donor head or get a new one.

I have welded a tit on the end of bolt. Have to be careful of aluminum, Heats up bolt too, Also peen the tit, and add some more weld, to get enough to get a pair of vise grips on it, a little back and forth.. Could put shield around bolt when welding it..

First, never use a HSS or carbide tool in a part you need to keep. Grind, file or chisel off the frozen stud. Use a tiny cold chisel to make a screw slot. Apply a penetrating lubricant, kerosene or similar. Try screw in then out several times. If that fails use a satellite drill to remove the stud core. Then grind down a hacksaw blade, cut radially out to the full thread depth on both sides, this will weaken the joint to some extent. Use the tiny cold chisel and tweezers to loosen and remove the pieces of the stud.
If you can’t get a stellite drill you will need to use ultrasonic or electrochemical erosion.
Before you replace the stud tap the hole, very carefully, with a plug or bottoming tap. Use the best cutting lubricant you can get your hands on. Then buy or make a stud at least 50% longer than the original. Also, buy or make a high tensile collar, for the extra length. Cross sectional area of the collar should be the same as the bolt core plus about 20%. Then tighten the nut on the new stud. The extra length will work as a really stiff spring to accommodate, to some extent, any differential thermal expansion.
Wherever possible add 75% to the stud length. The collar can be made from a Grade 12.9 bolt or a Grade 8.8 with extra area if the studs are Grade 12.9.

Always use an anti seize compound.

rmierisch said:

Always use an anti seize compound.

Click to expand...

If you going to use anti seize don't use the aluminum based ones as it just seize the bolt from the heat which is the problem currently where the aluminum has melted and seized the bolt. USe Copper based anti sieze on exhaust bolts if you must use an anti sieze compound as it has a much higher melting temperature. Whatever you do don't the copper base anti seize in marine environments as it is deadly marine and fresh water invertebrates.

The Toro Timemaster 30 inch is a fairly pricey mower. Probably worth putting a new engine on it,skipping all the hassles and issues of an iffy repaired engine. My opinion only :-D

I have had good luck with Kroil penetrating oil. It would be worth a try.

Hope you've gotten it out. If not, here what works. If you still can, drill the bolt out as much as you can, then weld a flat washer onto the end of the bolt if it's flush, while filling the hole in the bolt your drilled. Yes, you'll want a Mig to do this. Then, weld a nut onto the washer. The idea is to unthread the bolt while it's still hot. Probably not redhot, but shortly after. If you don't have a mig, don't try this with an arc, find a friend with a mig and you'll get it out. I'm not a machinist, but this has worked EVERY time for me over the last 30 years.

Broke this off just for you guys.

Hammermechanicman said:

View attachment 57006

Broke this off just for you guys.

Click to expand...

Now get it out for us.. LOL

I will. Center punch, cobalt bit, bottom tap. The engine may not be worth saving. Off a troy Bilt pony tiller. Guy ran it low on oil. Rod fine but seized the crank in the sump cover. Has the camshaft reverse. Saved the crank but if i can't find a sump cover he may be out of luck.

Hammer just wants to be a show off...<LOL> Either that or Murphy just showed at his place.

I stripped out a 330000 oil pan retaining screw Saturday just torquing to 220 in/lb. I done it enough to know screw position #9 will usually do this. Boy I glad I got the Heli coil kit last year. Now I just want try to install the 16mm coils instead of .469" ones. The hole looks deep enough. But even the .469 5/16-18 coils will torque to 21 ft/lbs so I am not worry that they wouldn't hold at 18.3 ft/lbs.; just like having things fully threaded so it off to McMasters I surf. Beside I need a 12" 1" x 2" section of tool steel for a puller I am designing here.