I was sent these photos. They are from a JLG telehandler steering linkage. The story is that the mechanics assigned to replace the ball joint between the steering cylinder and the track bar couldn't break it loose from the bar. It was put in a vice and heated in an attempt to loosen the threads but with no success. Just as they walked away from it to think about a Plan B to try to break the thread loose the joint exploded as you see in the photo. Fortunately nobody was hurt. There must have been some major force inside that ball joint to peel it open like that.
Wow, have had to do the same thing, never dreamt it could do that! Will file that one away....
At a former job, a couple guys were trying to get a drag link off a Phoenix mixer with heat and it blew the crimped cap off with a LOUD BOOM! It narrowly missed a guys head and went the width of the garage [75' or so] and hit the wall next to me. We chalked it up to hyd. pressure from the grease expanding in a confined space. Scary stuff indeed.
I'm having a hard time understanding what causes the catastrophic effect. Is it uneven heating and cooling to a hardened material? Is it trapped fluid? What could cause that release of energy?
I did that exact thing on a G12 JLG a few years back. It split in half and puked grease smoke out all over the shop. For some reason JLG is horny for loctite on those threads. I swear they fill that damn cavity full before threading in the tie rods. A 4 or 5 foot pipe wrench with 2 guys is usually needed to bust them loose when cold. With heat its a one person job. We actually bought a big tap to clean all that old loctite out so we could thread them back in by hand. New loctite of course but not half a litre like was in there originally.
WOW! I will definitely keep that in mind and pass it along. WOW
I haven't seen one cut apart, so I'm speculating here. I think there is a nylon/polypropylene/plastic thrust washer inside the socket part of the joint. Is it possible that heating it could release some sort of combustible gas that combined with the grease in the joint could cause an explosion..? One thing I have no idea about is how hot the guy with the gas axe actually got the piece before it went bang. For all I know it could have been red hot.
I think its just from the hot air/hot grease expanding in behind that ball stud. With all the movement during turns the surfaces of the ball and socket probably get super polished and seal up tight so nothing can vent out around it. When the one I did popped I had it warm, not near red hot, focusing the heat around the flat spot by the threads. After that I started heating the end of the steer cylinder rod instead. Never had another one pop again.
This all got me to thinking. Something I'm really not a fan of. We had a class on hydraulics when I worked for the Volvo dealer. The instructor explained that we ALL need to be more cognizant of where we apply a torch. Something I had forgotten about from automotive times. Some bearing side seals as well as high pressure o-rings contain flourene, iirc which when heated produces a carcinogen which becomes caustic and aggressively attacks animal tissue. The result would require the surgical removal of affected flesh. I have personally never witnessed or observed this. Only what I've been taught and passing on to all of you. Perhaps flourene is not the proper name. I looked up msds sheets and show no long term or chronic effects from decomposition.
I have heard that is a very common thing to have happen on tie rod ends and u joints, ball joints etc. I heard about it a couple of years back. Scared me thinking about how many I have heated.
Found it , viton. Viton , the tough little brown ones. When exposed to heat (315*C) release poison gas, when combined with water makes painless burns resulting in tissue death. Check msds for detailed information. Bottom line. Be mindful of what you're burning, not just what you see.
I had heard of that fwf, but had forgotten about it. Thank you for the reminder.
We all need it from time to time. I guess that's why I'll never B!tch about going to an annual refresher. I had completely forgotten about all this, till Nige posted about the rupture hazard. Another that I'd have never guessed in a million years. Thanks Nige, got the old noodle working a bit.
Cut one apart. I don't think the wearing surface in the female end of the joint is Viton judging by the colour. However whether or not the combination of fumes from hot plastic and grease can make a more explosive combination than just grease alone is I think still a valid one.
We had something similar happen in our area a number of years ago in a shop that works in the hydro-electric industry. A guy was heating a cast steel prop to remove it from the shaft. The prop had a small casting flaw which had over time filled with water. As he heated it up the water turned to steam and eventually blew out and a chunk of metal hit him in the neck, killing him. Makes you stop and think about how many times we've done things like that.
The burning/overheated Viton is nothing to mess around with. When burned it produces hydrofluoric acid which is one of the strongest acids known. The odd thing is the burns don't have much pain until they are very deep. They are also hard to stop - baking soda won't work, you need a specific base made to neutralize HF and even that is a crap shoot. Burns often require surgery. Hydrofluoric contamination is a serious problem on vehicles that have been in a fire as the Viton residue is very contaminated with HF and remains active indefinitely. Only certain gloves are resistant to HF. Choose wisely.
Yup, there are specific warnings in the Detroit Diesel manual about melted down crosshead pistons with burnt seal rings under the piston crown.
Nige, I do declare, you've posted something I've never seen before, and I'm damn sure curious as to what caused that. Strange indeed in that the only logical reason the wrench bender is replacing the joints is because they are worn. Rubber seal has long gone, grease lube quickly follows in being long gone, joint wear progresses until it's worn slap out. As a matter of fact I'm doing this very repair on a Genie 1056 telehandler for the same reasons. So...with all this slack and worn out stuff, what-in-the-heck caused this failure? I'm perplexed!
A lot of times in the extreme cold up here the steering cylinder seals blow out. Unfortunately that means the tie rods need to come off so the cylinder can be resealed.
I would like to know myself as I have torched numerous ones off with no problems.
I have seen it happen to ball joints on a pickup also maybe the melted plastic forms a new very tight seal as its expanding ?
My guess is the joint was heated up real good the innards melted causing pressure no-doubt, not the first time I've seen that. Stopped a young fellow some years ago from cutting a sodium filled exhaust valve in two. Makes you wonder how many people injured heating stuck u-joints/using a bottle jack as a press. Truck Shop
What I don't understand is why a torch is used to remove tie-rod ends and drag links. Truck Shop
I think 92U 3046 in post #5 on Page 1 touched on something ........... JLG's horniness for half a bottle of Loctite on those specific threads...... I haven't checked but apparently the Service Manual instructs to heat the rods attaching to both ends of the knuckle to break the threads loose. I'll have to read the procedure in detail
EXACTLY! I haven't done one yet that wasn't a total bitch. LOL
Actually I was referring to steering components as in large tie rod ends and drag links stated in some of the posts above. Truck Shop
if locktite is involved 4 to 600 degrees does the trick
Concrete slurry works it's way into everything, that and the acidic cleaners lock threaded fasteners up tight. Most guys went for the heat to loosen drag links and tie rod ends from the tube they were screwed in to. I used ATF and acetone with a 12oz hammer to loosen them however.
Here's the Dana axle Service Manual procedure. Personally I don't think heating to 100 DegC would be enough to break a Loctite bond on the threads. And that procedure looks all fine and dandy with the axle out of the machine and in a holding fixture, I'd like to see them do it like that with the axle still in place ...........
Typical service manual where it is OUT of the machine and in the open. Have always used heat on similar stubborn threaded bustards but not to blacksmith levels of heat just enough to break down the Loctite or bonding materials, would never have considered a explosive effort as shown.
I wonder if someone( dumbass) pumped some substance ( an epoxy or similar)inside of the worn joint trying to get some more time out of it before replacing it??? and that hardened and made a seal that kept in heated gases to cause what the pictures show....I have replaced ball joints like that on the front of a john deere tractor, but wrenches got them off and no heat needed, but this brings new cautions to heating a grease filled ball joint..
Well no real concrete conclusions, but it sounds like far too much heat was used, plus the heat was applied mainly to the ball joint not the cylinder rod. Sometimes I wonder if certain people should have a "not permitted to work without adult supervision" tag hung round their necks.
Some need that tattooed to their forehead!
Kinda "Here's your sign" deal, right..?
Thanks for posting this Nige. You prompted my memory. A number of years ago we had this very topic featured in a safety seminar after a company mechanic narrowly escaped serious injury. He was using a cutting torch heating/cutting a frozen u-joint next to a carrier bearing on a loader. It had enough force to severely damage a nearby hydraulic hose when it exploded. He was lucky that he was reaching in and the machine shielded his body. His arm got some bounced shrapnel and a finger got smoked thru a leather glove. They then showed us a dozen examples where people were injured or killed on everything from mine trucks, to exploded PTO drive links, to a exploded propeller on a outboard motor. All from using to much heat on them. May not happen often but if the conditions are right it does happen.
Wish I could find the actual report but a couple years before I retired some guys at a different part of the company had a incident related to heating to remove an impeller on a water pump. As I recall this water pump had an impeller that screwed on to the shaft and the threaded hole was a blind hole! After not having any luck breaking the impeller free they decided to grab the gas-axe. Not sure if there was water, oil or something else inside the threaded hole but while heating the center of the impeller exploded out. I can imagine that it is possible someone had installed the impeller with grease or ani-sieze and that is what caused the explosion. Do not recall if there were any injuries or worse.
How that you mention it, I believe there is a post here somewhere that details that incident.
Not post #15 on Page 1 that you're referring to is it..?
Don't think that was the same accident as I'm pretty sure the one I was referring to was a water pump that one refers to a propeller, I'm thinking that means a boat, not an impeller on a pump. But still same idea.
Well the search function for this forum is a great tool. Just did a search for my name and searched for "impeller" and there it was:
The first thing when heating u-joints is to remove the zerks and stand to the side. Also the use of heat temp paint stick helps prevent over heating of parts. But the other killer that is not mentioned in this thread is the improper use of a press. When pressing bearings a scatter shield is a must-no if's, and's, or but's about it. Think of it this way-a 1/2" ball bearing is a 50 caliber round and can go through three walls at the blink of a eye. I was in a auto parts/machine shop store years ago buying some brake shoes for my pickup when an incident like this happened. The ball bearing just missed the sectaries head in her office after it already had passed through two walls one being the restroom. The ball was finally stopped by a 2 X 4 stud in the wall of her office. No joke presses are deadly as hell. Truck Shop
Have run presses most of my adult life, ALWAYS some form of shield on the press or the materials being pressed. Actually saw a Hendrickson beam fail installing bronze bushing, the kid doing it THOUGHT or failed to that the beam would square up as it was shoved in. Chunk the size of a average dirt clod scattered across the shop.
Good vid 92U Truck Shop
Had one a couple of weeks ago in field repair Dana front axle on deere tractor tie rod had snapped off at the joint., ball seized in with rust heating up as locktighted threads in end of joint where screws into steering ram noticed one side off joint starting to swell, stepped back joint swelled some more then blew a small hole in the side and a fine jet of flame approx two foot long shot out. made a loud bang and had to sit down awhile is fairly common to have to heat the end to burn the locktight to get them off usually the joint is worn and sloppy and you do get a bit of smoke I think in this case as the joint was seized with rust pressure built up at the back until it blew a hole through the side
Another area that is often heated to free a component, Would include a brake caliper bracket slider pin. That often tends to rust and stick. I have over heated per say in attempt to free stuck pin to have experience the separation occur in a split second! Like a rocket!!!
I suspect that is also what happened to the joint that was the start of this thread. That was also a Dana axle. I’ll be honest *** was my first thought when I saw the joint after it let go. Like you I always imagined that a worn one could not seal sufficiently to build up pressure in that way.
I think a funny one is when a grease fire/flame up occurs and windshield washer fluid is used to put it out.
Never saw you show your "dark side" like that before.
WHOOPSIE!! POOF!!