Anyone working on equipment comes across this situation - broken bolts and broken studs. Anyone want to share their ideas on how to accomplish the task without damaging the base? This take was different than the usual heating, beating and extractor methods that failed this repair. My idea here may not be new to others but it is what I came up with to remove a broken water pump mounting bolt (3/8"-16) in a John Deere 6619AT engine in an 862B elevating scraper. I purchased this used unit several weeks back and realized, after the purchase, that there was a coolant leak. I should have walked on the purchase and kept looking but stitches and cold weather limited my due diligence inspection. The leak was from behind the water pump mount. The cause was a broken bolt or stud that left about 3/8" sticking out of the block. No picture was taken of the original offender as I did not expect this to be such a problem extraction. I tried the usual tricks - grind a couple flats to enable grip with locking pliers, lots of penetrating oil, gentle heating (but not so much as to harden the bolt any further), shocking with hammer to loosen, etc. Nothing I tried allowed this stubborn bolt to budge. Time to think about this - very limited work area unless I pull the radiator, I don't want to damage the block, I need to get this done properly without buggering the assembly, etc, etc. Limited access work area - most work done from top down I do have a lathe and vertical mill in the shop. I do have some rudimentary machining skills from high school shop education that tend to get me by most of the time. I needed a good approach to drill out this problem stud, correctly, and maybe an easy-out could extract it? Dream on - life ain't that easy. I still had about 3/8"+ of the stud exposed after flat grinding and hammering on the fastener. The threads were too mashed to allow a nut onto it. I chased the threads with a 3/8-16 die to restore what I could. I needed a long nut to enable a drilled out 3/8"-16 bolt to act as a drill bushing in order to provide a square approach to the damaged stud. I had one hand available in the alloted space to hold and pressure the drill so the drill bushing is a must-have. The battery bolts used on a group 31 battery on the truck were perfect for this application and I had some in stock - just needed to punch out the end cap for a through nut. A 3/8-16 x 1" bolt was drilled through on the lathe in order to act as a drill bushing - use the same diameter drill for the bushing cut and the pilot hole on the stud. Using the long nut on the damaged stud, the "drill bushing" could be set tight on the stud to commence drilling squarely. I use a Left-Hand set of extraction drills for these studs. The drills are great and super sharp but the extractors are too soft for such a difficult stud. The extractor method did not work but I did have a square pilot hole . "Drill Bushing" for starting a square pilot hole on the damaged stud. So, after the failed attempt at the extractor method, I was on to phase 2 of this repair. Thinking again - make another drill bushing in order to enlarge the hole and re-tap it. This water pump mount has an intermediate mounting plate that bolts onto the block and makes a perfect bushing mount. The holes on the plate measured 0.440" so I cut a stepped bushing at 0.010" over for a press fit into the hole and left another 1/2" of the 5/8" rod stock exposed above the plate. I needed to drill out a 5/16" hole for a 3/8-16 tap so the bushing was drilled out at 5/16", cut to 0.450" small diameter @ plate thickness with a light chamfer to allow an easy press fitting in the vise. Fit was perfect and square. I had 3 bolts to attach plate to block with bushing squared up to previous drilled hole. Drill bushing for intermediate plate Once I got the rest of the hole drilled out to diameter and depth, I tried to tap it with NO LUCK. 2 different taps and neither wanted to get started even though everything was to spec. Again, I was in a limited space to work with minimal pressure available to get these taps started. Thinking again - tap the bushing on the intermediate plate and THAT will provide the pressure needed and a square start to tap the hole. Pulled the plate, tapped the bushing and reinstalled the plate. Tapping the block hole was flawless with this technique and the threaded hole was restored, squarely and properly. I have to remember this trick - make up a bushing mounting plate for a square approach to repair broken/damaged studs and bolts. No one showed me this trick before so I was sort of in the dark as I went along. Might as well share it and pay it forward to help someone else. Getting the tap started with the intermediate plate pressed in bushing I should get the rest of the repair completed later today. New gaskets were cut last night and RTV glued to the intermediate plate so install should be a little easier with fixed gaskets.
Nice job! One of the tricks I keep up my sleeve is a 90 degree mini die grinder with a 1/8 collet. Drill through the bolt as large as you dare and then take the die grinder and grind 3-4 slots in the bolt until you start seeing threads. At that point I use a tiny chisel to break out the pieces. Run a thread chaser through the threads and you are back in business.
I like these both. Has anyone tried the induction heaters? I keep seeing video's of them, but don't know if its worth it. I'll admit, I have rare luck with easy outs or drilling. I weld a washer to the broken off bolt, and a nut to the washer. Repeat until it comes out or I give up.
I prefer to use torx bits rather than ez outs, if done right they bite better, and they work both directions.
This job was so space limited that this was the only feasible option. Unless I wanted to remove the front and radiator in order to gain access and working room. Worked good and taught me something new to me.
I’ve got an induction heater. Snap on guy promised me it was the answer to all my prayers. I’ve used it 3 times in about 7 years and it worked once. I can see where it would be better than a torch but I just haven’t had any jobs where it shined.
Those Snap-on guys sure do talk sweet, don't they? Joe H
It isn’t even snap on branded. Can’t remember the name…
Most useless Snap-on tool I ever bought was a pneumatic gasket scraper. Been sitting in the bottom drawer for about 40 years, why don't I just throw it away? Joe H
I’ve never seen one. Obviously it didn’t work?
It looks like a little needle scaler with a blade on it. Vibrates the blade in/out maybe 1/16 of an inch. Looks like it would work but just not worth a damn. And digs into aluminum if it gets a chance. Joe H
Nice set up. I keep around set of the Gators tap blocks. Also have Ridgid straight flute extraction kit. That one also has drill bushings in it.
Air gasket scrapers are great for cleaning a mower deck. Ed
I have a Snap on Scraper like Joe H of the same vintage. Got mine in 1987 and have used it a lot. It will bite into aluminum if not carefull. Very handy for removing old Cat glued gaskets. I use super thin transmission oil in mine and still runs. Simon C
This. weld a washer so you have good access and visibility. Than a large nut, for that 3/8 use probably a 5/8 nut. Fill completely full of weld, hotter the better. The way this was explained to me is that the heat gets driven down into the bolt, helped by the electrical currents. LET IT COOL completely, ie grab and hold cold, so the bolt can shrink back down. Can be repeated but best result is first time,
how about the wax trick. IIRC melt some wax into the threads of a broken bolt and it will lubricate the threads making it turn out easily?
3 PIECE BUST-N-OUT KIT FOR 3/8" ZB375 | Matco Tools www.matcotools.com pretty expensive(not sure who actually manufactures them) and as far as i know only offered in standard sizes but work well for bolts that break off deeper than flush
My absolute favorite is this Pneumatic air hammer attachment. You put a socket on the end that applies the shock force then a wrench above it to apply torque back and forth. Really great for exhaust studs welded bolts/nuts, etc. Its great because you can just hammer away with no negative consequences as the you (the wrench) can really feel how much torque you want to give it. Highly recommend. and of course the old homebrew kit of acetone and ATF
The only extraction method I have ever had consistent luck with is welding a washer and nut on. The normal array of extractors tend to be junk because they break easy or slip easy. Heavy equipment broken bolts often need a heat cycle to break the rust and jammed thread bond as well. Unfortunately, like you said, limited room means limited options.
Arc welder with unichrome rods welding on a cat hardened washer first then a nut is the best I’ve found. If you have 4 inches clearance above the stud you can get it this way.
What brand is that? Where is it sold?
Google search for screw knocker or old man tool. Bonus if you find one for .498 shanks.
Thanks, found it!
I've also had good results with the welding method, even when the bolt is broken off below the surface. If you clean the top of the stud as best you can you can build it up with a MIG to where it protrudes and then weld a nut to the stem you've built. I fill the center of the nut and get it real hot and then use a light duty impact driver to back it out after it's cooled. Works nearly every time, and if the nut happens to twist off repeat the process. I've never had to do it more than twice.
Mayhew #32029.
Those Arctec Unicrom rods were very expensive 20 years ago. They must be really outrageous now
Astro tools 49804 is the big shank bolt buster for air hammer.
https://www.fortishd.com/wp-content/webp-express/webp-images/uploads/2023/05/Air-Hammer-XL_0-1.png.webp
Gotta love Amazon....
weld on a nut worked for me too. I had a good one, a rotten exhaust stud on the IO-470 in the 310. There is no room in the nacelle, so I tapped a thin castle nut on the stud and blind welded the nut to it with the wire feed. I got lucky it came right out. I used to keep that "bolt" around as a souvenir. It represented not having to pull a jug and all that entails.