Briggs and Stratton Stuck Exhaust Bolt

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.
 
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

| Toro

www.toro.com www.toro.com
 
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.
 
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.
 
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