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Best way to free a seized pivot bolt / joint ??

2010-07-28 00:00:00 172675  drconsult

Greetings. I have a John Deere 420 loader that has a siezed pivot joint below the upper loader arm near the cab. The large pin (about 1" diameter) appears to be seized onto the round part that is welded to the hydraulic cylinder and rotates as the loader is raised/lowered. This snaps the small 1/4" diameter pin that is designed to prevent the 1" pin from rotating.

When I bought the tractor (used) that joint was missing the grease fitting and it won't take grease despite cleaning and installation of the new fitting.

I removed the grease fitting, cleaned the hole and the entire area. It's been soaking with WD40 sprayed all in the hold and around the joint for 4 days and still hasn't freed up. I even tried to tap the 1" pin out (gently) with a sledge hammer, push on the end with an air hammer and it just won't budge.

The loader will still work but will wear the pivot point collar since the 1" pin is designed to be stationary.

Any other ideas on how to free up the pivot joint? Or do I just need to heat it and beat the heck out of the 1" pin?

Thanks.
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Best way to free a seized pivot bolt / joint ??
2010-07-28 00:00:00 172677  kthompson

well if I followed all points my guess is the pin has seized to the bushings or both are scarred either they are locked together physically. If so you possibly will need to replace the bushings. If you heat the pin it expands making removing it worse unless you are heating it and then allowing it to fully cool it is possible that might break it loose but normally you would heat the bushing as it explaining should loosen the pin. Doubt WE 40 will prove to be much help for think you are past rust being the issue. If you have a pulley puller that would fit it might could push the pin loose but it probably would take a large one.
Think you will find heating it to give it some movement and the use of a good size hammer to be what it takes. Be sure you have the weight off of the pin and you may wish to have someone slowly operating the loader to see if there is a position where it moves. You might need to hammer on the end not drilled for the pin as that end may swell easy.

One other thought with potential damage to the bushing, get a grade 8 bolt for the retaining pin and it might be strong enough it does not shear.

There is still one other thought but think the pin is too long to consider, drill the pin out being very careful to be centered and straight. Do not drill through the pin side walls but close enough you could take a hammer and punch or chisel and collapse the walls of the pin in.

Working on about same job myself except the pin snapped leaving damaged bushings. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-28 00:00:00 172680  earthwrks

Picture an arbor press on its side. Recreate the principle using whatever is handy keeping in mind you'll need room for the hydraulic jack.

Be careful beating on it as that could displace enough material to expand the pin in the hole. The technical term is staking.

You might want to talk to a heavy truck mechanic (Kenny that doesn't mean what you think--the truck is heavy, not the mechanic) and see if they have a ball joint/tie rod press. Looks like a big C clamp. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172681  harvey

I'd try some Blaster or othe penetrant. Then try a hardened 1/4 inch bolt.

Otherwise I would have to concern about take loader off tip on its side and WHAIL the snot out of the pin to remove it. then put in new bushing and pin. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172682  auerbach

If there's a Parts Source store near you (as I have in Waterloo) they'll loan a front-end kit containng a wide array of pullers. You leave a credit card slip for its value (around $250) and get it back if you return it the next day or so. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172684  Murf

First off, put in a new grease niple and insert it.

Then get a 'grease blaster' (likely available at Princess Auto or any good auto supply place. It's sort of a hydraulic cylinder with a grease fitting in the end of the piston rod. You put it on a grease fitting and give it a few good hits with a dead blow hammer and it injects grease at very high pressure.

If that still doesn't work, get a 'plumbers soldering blanket' at Home Desperate or any building supply place. It's a small fire-proof cloth that is widely used in the plumbing industry when soldering pipes near wood framing. Put this in a circle around the seized pin and with a small propane torch heat the end of the pin as much as you can without heating the FEL frame. Then while it's hot try giving it more grease.

If none of that works, get a powerful drill and make a good-sized dimple in the end of the pin, then with a stout punch and hammer, give it some persuasion.

Best of luck.

....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172685  drconsult

Thanks for all your suggestions and fast replies!

I haven't tried a graded bolt yet but it did snap a brand new JD retaining pin like it was a match stick. Maybe a combination of heat to the bushing and a graded bolt while moving the loader might work. I'm reluctant to put too much heat on the bushing because I'm afraid it might weaken it. Would a regular propane torch be appropriate or should I use the heating attachment for my oxy/acetylene torch?

I'll check out the Parts Source but I think most automotive pullers would either break or bend the loader frame. It's no problem destroying my tools but knowing murphy, I don't want to break one part of a $250+ puller set.

The arbor press idea is a good one. I was thinking of making a press/puller using a small hydraulic jack an some chains. The trick is a backer plate on the back side with the right size hole drilled in it for the pivot pin to pass through. If the backer plate isn't contacting the collar/bushing it could bend the loader frame. Maybe it's best to take the loader off, tip it on it's side and use an arbor press or try a hydraulic press. However, the hydraulic quick disconnect collars are seized as well but that's a whole other can of worms.

If all else fails, drilling it might be the only answer.

Thanks again for the suggestions.

I'll post a follow up with the solution.
....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172688  auerbach

Operating the loader could help, but I'd jack up the arm just enough to neutralize its weight. Then I'd try to combine the steady and accurate positioning of a press with the added persuasion of sledge blows.

Murph: glad to know about that grease blaster -- just what I need. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172690  Murf

A couple of things;

First off, a propane torch is all the heat you will need.

Secondly, as backwards as it sounds, you want to heat the pin not the bushing.

The reason is, you want to drive the grease into the seized area. Enlarging the bushing will create less pressure not more. By filling the cavity with grease, and heating the pin, it does two things, first it thins the grease, but more importantly, when the pin swells it leaves less room for that thin grease, it's only solution is to go where there's no grease, the seized area.

Finally, I wouldn't try moving it as a solution. The seized spot is likely from corrosion, turning it will only chew up the bushing more.

Best of luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-29 00:00:00 172694  drconsult

As it turned out the problem is more severe than the grease blaster can fix. I even removed the ball bearing from a grease fitting and spare coupler, cleaned the fitting out and tried to put 150 psi of air into the joint to force air and penetrating oil into the bushing but no luck.

I did try heating the bushing (with the grease fitting removed) and tried several times to move the pin but no luck. I'll try with a new grease fitting installed and as much grease that I can fit in it before heating the pivot pin this time.

Keeping up the fight....

Thanks for everyones help!
....
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Best way to free a seized pivot bolt / joint ??
2010-07-30 00:00:00 172705  kthompson

FYI, 150 PSI air is decent pressure but a manual grease gun is a few thousand. Think you might find them rates about 7,000 psi or so.

Make one suggestion to you, patience here. Look at each option carefully and might try each to a degree or combo of to decide which needs to be your action...then realize it will be slow. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-30 00:00:00 172708  hardwood

These guys are all wrong. Load up the tractor and loader come across the border and trade for a whole new outfit, problem solved. I don't keep up on Canadian economics, but the report this morning was a bit bleak for the US of A, we need all the help we can get, plus a few less freeloader politicians. I won't name names tho, you can fill in the blanks. ....
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Best way to free a seized pivot bolt / joint ??
2010-07-30 00:00:00 172710  drconsult

I understand that grease guns produce several thousand PSI but when the grease (essentially non compressible) fills the fitting, there is only a very small cross sectional area for the pressure to act on. Using a fitting threaded directly into the hole (more than 4 times the cross sectional area of the little ball bearing in the grease fitting) and a air (compressible and several hundred times less dense than grease) there would be more penetration. I freed up a different joint using the same method. It didn't take grease until I sent the air through it and then it took grease just fine and pushed a bunch of dirt out of the joint.

I'm considering all options and trying every suggestion so as to not damage the joint. Your heating the pin method didn't release it but one of these days it will come loose.

There's no magic bullet here and I'm trying / re-trying every suggestion multiple times.

Other than the stuck pivot pin and hyd qd's, the rest of the machine looks and runs great (only 400 hours on it to boot).

PS - Don't you love how a stuck pivot pin thread turns political? :) ....
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Best way to free a seized pivot bolt / joint ??
2010-07-31 00:00:00 172714  kwschumm

Nobody has suggested this so I'll throw it out there. When I have bolts seize the first thing I do is reach for the air chisel with a blunt tip and vibrate the bolt a bit and then the area around it while turning it loose. Turning it doesn't work so well for a pin like you are fighting but I can't help but think that if you could vibrate the pin back and forth while spraying some PB Blaster or other penetratant you might make some headway without drilling. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-01 00:00:00 172734  drconsult

I've been doing that as well KW. The air hammer wandered when trying to push on the end of the pivot pin so I drilled a small dimple to accept the end of the blunt point chisel. It makes for a nice point to keep the drift pin from wandering too.

In between the other suggestions, I've been hitting it with penetrating oil (Sea Foam's Deep Creep and Liquid Wrench), heat, air, grease, etc. The Deep Creep is designed for freeing seized engines and is pretty thin stuff. I couldn't see PB blaster doing that much better of a job.

If it doesn't give after a few more cycles of heat, penetrating oil and the hydraulic jack press (still building that tool) I have no problem destroying the pivot pin by drilling it out. It would be nice to get ahold of a magnetic base drill/mill to do that instead of using a hand drill.

Unlike the last owner, I believe that grease fittings and grease are cheap compared to this pain in the rear...

The best solution is to not get into this problem in the first place... :) ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172775  Murf

Quote:
Originally Posted by drconsult | view 172710
[QUOTE=drconsult;172710] I understand that grease guns produce several thousand PSI but when the grease (essentially non compressible) fills the fitting, there is only a very small cross sectional area for the pressure to act on.

Using a fitting threaded directly into the hole (more than 4 times the cross sectional area of the little ball bearing in the grease fitting) and a air (compressible and several hundred times less dense than grease) there would be more penetration.[/QUOTE]

Nope, you've got that backwards there friend.

Because grease (being a liquid) is not compressible it exerts far more pressure. That is the whole principal of a hydraulic system, if you exert 1,000 pounds of pressure on a 1 sq. inch surface that is hydraulically coupled to a 100 sq. inch surface you will be pushing with 100,000 pounds of force even though you only started with 1,000 pounds.

Now what might finally work is a last chance (and I hate to even mention it) down'n'dirty solution that I've had to resort to myself a few times. Get a small diameter hydraulic hose and put a QD fitting on one end, and a grease zerk on the other. Connect it to a remote on the tractor and give it an extremely short burst of pressure starting with the machine idling and slowly increasing RPM's between unsuccessful attempts.

NOTE: a hand pump is way safer though if you have one since you can very slowly build pressure.

BE VERY CAREFUL though, wrap the whole issue in clean white rags (they will show wetness faster) and be aware that when it clears it will likely spray oil everywhere. You don't want to be any closer than required!!!!


Best of luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172777  earthwrks

Murf: "...a grease zerk on the other."-----did you mean a grease zerk COUPLER on the end? ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172780  Murf

Quote:
Originally Posted by earthwrks | view 172777
Murf: "...a grease zerk on the other."-----did you mean a grease zerk COUPLER on the end?


Yes, I just wasn't clear enough, I should have said "grease zerk coupler".


Best of luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172782  kthompson

If you end up looking at drilling it, check for small local machine shop and see what they can offer. They might be able to drill/bore it cleanly even while on the machine. Doubt this will work for you due to diameter of the pin but if beating it one direction does not work and the other end has hole through it for retaining bolt you may do well to drill and tap as large bolt hole as reasonable in the end you have been trying to drive. Then you could use that bolt as source for large impact wrench and see if it can move it and or to pull the pin out that direction. The vibration of impact wrench probably will be much more than the air hammer. I have one other thought and have no idea if you have the room for it. Get solid support under the bucket and cut the pin. You must have sufficient room for blade. Then dealing with what should be three shorter pins it might be easier. I suspect you will not have the room needed for a blade. But there are some thin cut off blades out there. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172784  drconsult

Murf: I didn't say there would be more pressure, there should be more PENETRATION of the air into the small spaces between the rusted parts because the oil is much thinner than the grease. I also tried putting penetrating oil in the hole, replacing the grease fitting and adding grease to it with a pneumatic grase gun. The same was also tried with air instead of grease. I wasn't trying to apply the most pressure but trying to force the most air, oil or grease into the bushing that I could.

The idea of connecting it to the hydraulics on the tractor is a good one but isn't the output if a pneumatic grease gun and the tractor hydraulics both around 2,000 psi?

My next trick might be slowly applying a few thousand psi of air over the penetrating oil and leaving it pressurized. Maybe the best advantages of penetrating oil and the pressure of a grease gun combined?

And yes, protecting the whole area from high pressure oil spray is required. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172785  drconsult

The large bolt and the impact wrench is an idea. Without a magnetic base mill/drill it would have to be done by hand. The pivot pin is about 1" in diameter so there's a bit to work with if the hole isn't dead center. It would have to be straight or it would break the tap. Maybe chasing the hole with a reamer or end mill might help...

It's a very tight space to get a reciprocating saw into but a blade might fit. I could support the loader and take the front tire off to make room for the saw.

The loader works but the wrong section of the pivot pin is rotating and it will wear the collars that are welded to the loader frame. The pivot pin is only stuck on the part that is welded to the rod of the hydraulic cylinder.

It would then be easy to take the cylinder to the hydraulic shop press and make short work of whatever was left of the pin.

Next question; How do I get the air out of the hydraulic lines once the cylinder is re-attached and everything is repaired?
....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172788  Murf

Quote:
Originally Posted by drconsult | view 172784
Murf: I didn't say there would be more pressure, there should be more PENETRATION of the air into the small spaces between the rusted parts because the oil is much thinner than the grease.


Again, it's not logical, but that's not the case.

Grease is thicker, no doubt about it, but believe me, if you compare oil under ~125psi and grease under 2,000psi, the grease will win hands down.

You can, and I have, used 10W-30 in a grease gun, and it works just fine, but, again, it won't go somewhere grease won't.

Just because grease has a higher viscosity does not mean it won't penetrate into thin gaps between surfaces.

I use a special lithium grease on some of the parts of my aircraft where the clearance between parts is sometimes only 0.003" and the grease squeezes right out when it's full.

As for pressures, yes, a good pneumatic grease gun can make very high pressures, but even the best guns only make ~40:1 ratio, so if your shop compressor could make 125psi, it would be making 5,000psi, but the usual 'cheapies' are only around 10:1 ratio, so if your compressor was only making 100psi, you would only get 1,000psi out of it.

By comparison, a good manual gun makes more than that. The regular old Alemite pistol-grip grease gun makes 7,500psi. They make a high-pressure series that creates 15,000psi.

Maybe that's the problem. What kind of grease gun are you using?


Best of luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172789  hardwood

Ok, now I'll give you my real thoughts on the pin other than trading the tractor off. More commonly known as the "Hot Wrench", Acetylene torch.
Drill a hole thru the center of the pin, have a person who is good with a torch with a new or fresh tip, now I said "GOOD" with a torch, not like me. Shield behind with something to keep the heat away from anything flamable. Fifteen seconds or less the pin is peeled out of the hole, very minimal heat damage to the bushings, or anything else. I'm not that good but have watched people who are.
Frank
PS, we're leaving after bit for a few days so your "Frank you're crazys" won't be heard.
Frank. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172793  drconsult

Murf: Ok, the pressures between guns are a bit different than I thought.

When working inside hyperbaric chambers with dive computers we have to keep them immersed in a bucket of water or air will get past the seals and the case will rupture on ascent. These dive computers were designed to be sumberged to 600' (267 psi) in water but only 130' (58 psi) of equivalent air pressure will cause problems. Water is about 300 times more dense than air at STP.

It's a different story when dealing with 7,500+ psi...

I don't know the name of the grease off hand but it's a red extreme pressure grease that's in a yellow tube from a major brand (something like Havoline, Texaco, Chevron...)

Hardwood: You are suggesting that I use an oxy acetylene cutting torch to burn out the pin from the inside? Maybe in the hands of a skilled mechanic but certainly not mine. And definitely not while the loader is still on the tractor....

....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172794  Murf

Quote:
Originally Posted by Murf | view 172788
Maybe that's the problem. What kind of grease gun are you using?


No, not the brand of grease, what type of grease gun are you using? Pistol? Lever? Pneumatic?

If you don't already have one, I'd highly recommend you spend the few bucks and get a good (Plews, Alemite, etc.) lever-type manual grease gun, preferably a commercial or high-pressure one, the difference is night & day.

I couldn't tell you the number of times I've put grease in fittings for friends that were unable to with their 'normal' grease guns. I have an older Alemite lever-type gun that puts out 10,000psi according to the manufacturers website. It has a handy 2 stage pump, you can set it to put out more grease at lower pressure, or less grease at higher pressure per stroke.

Best of luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-03 00:00:00 172797  kthompson

If you do try the bolt and impact wrench do use grade 8 bolts. For me hand tapping that would not be bad as long as you have the tap straight and have drilled the correct size hole and are using cutting oil. Skip any of those and it is most sad time. Years ago I worked for a major machine manufacturer and it would impress you the holes tapped using a normal air impact wrench. The sockets normally were a little loose on the tap and allowed the tap to align itself right well. I would think you don't need longer than an one inch bolt either.

As to removing air from the cylinders think cycling them will take care of that. Always has for any cylinder for me.

Hope you well with the job. You are very correct, properly greasing such sure beats replacment.

Murf, are there two stage hand grease guns? I did not realize there were grease guns that pump up to 15,000 PSI.
....
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Best way to free a seized pivot bolt / joint ??
2010-08-04 00:00:00 172816  jbjpam

I just now saw this thread. I also have a 420 loader and had the same stuck pin when I bought the tractor. The lubrication will have very little chance of working if the pin has galled and scored the inside of the cylinder pin hole. This creates an internal "snap ring" between the pin and bore. Basically it has welded itself together. My solution was to use a 3/4" diameter steel rod about 18" long and weld it 90 degrees to the end of the stuck pin at the middle of the 3/4 rod. Essentially making a "T" with the rod and the pin. (With the loader off the tractor.) Use a strong piece of pipe over the end of the bar as leverage to spin the pin as you pound from the opposite end. (With the rod sticking out equally on each side you can use 2 pipes if necessary to pry with, though I did not need to.) Once I was able to turn the pin in the hole a few times it did not take much to pound it out. Before you weld the rod on think about the the most comfortable position to swing the hammer from (whether you are right or left handed) and weld to the opposite end of the pin. Lessons learned on that one. You will need some JD green paint to touch up the weld splatter on the end bushings. Good luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-05 00:00:00 172831  Murf

Kenny, yes, there's 2 stage grease guns, both in manual and pneumatic versions.

The high pressure units can be handy, but for everyday use their not, like any other hydraulic system, higher pressure means lower volume. So using a high-pressure unit for normal chores will have your arm looking like Popeye in no time from all the extra strokes required.

That's why the 2 stage units are handy. The 2 stage pneumatic we have on the service truck switches between low pressure & high automatically based on the pressure it encounters, kind of like a 2 stage hydraulic pump does. Real handy for construction equipment maintenance, although our bigger units have an automatic greaser built right into the machine, you just keep the reservoir topped up from a bucket and it does the rest for you.

Best of luck. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-05 00:00:00 172834  drconsult

jb: We just tried that very solution and the steel bar we welded to it twisted and snapped.

kt: Impact wrench was a good idea but no dice for this one. Stripped and sheared the bolts or the wrench just danced around without budging.

murf: Not sure the name of the guns but one is a two stage. I squeezed on it pretty hard and the grese fitting popped out stripping the threads in the bushing. There's no way grease or any lube is getting into this thing through that tiny fitting.

solution (partial):

I used a reciprocating saw to cut off the pin and remove the cylinder from the tractor. Tried pressing it out and 20 tons of force didn't budge the pin. Tried drilling it out so that only a thin wall remained on half of it and pushed on the other side with the 20 ton press, no dice.

At least now the cylinder is off the tractor and it's easier to work with. I'll be taking in to a friends machine shop tomorrow to put it on the mill and cut / press the remainder of the pin out.

Those were all great suggestions guys but this ones match is going to be the mill. And if that doesn't work, I'm off to buy a new cylinder from the local JD dealer. At least the rest of the loader is still in one piece!

Hopefully this thread will stay active and others with the same problem can get some ideas to free their pivot pins from hard places... :)

Now I just have to get the Mercruiser Bravo 3 out drive on my boat fixed and I'll be all set...

Thanks again! ....
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Best way to free a seized pivot bolt / joint ??
2010-08-05 00:00:00 172835  kthompson

Did the pieces you in the frame come out OK?

I had shaft or pin on excavator bucket to snap in June and needed to replaced worn bushings. Look at that thread for thought that might work to finish getting the drilled out pin. It currently is in Hot Subjects and is Shaft for Bucket. Might be a solution there for you.

One that is not there and might work for you due to amount of metal difference is to heat the bushing (not the pin) and see if will expand enough to release the pin.

I don't find joy in our sorrow but your pin made mine look like a friend. Hope all goes well. If you end up damaging the cylinder there could be a pressed in sleeve bushing in there or you may be able to bore and sleeve it. I found a company who makes my bushings for $30 each while Volvo was only $90 each.

....
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Best way to free a seized pivot bolt / joint ??
2010-08-06 00:00:00 172864  hardwood

Drconsult;
Yup, I was as serious as an undertaker when I recommended the oxy/acetylene torch in the hands of a skilled torch person. With a pilot hole thru the center the pin would have been evaporated so quickly the bushings would have had little chance to been damaged.
I've did a fair amount of torch work but never enough build the skills of a pro with well maintained equipment.
Frank. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-06 00:00:00 172866  earthwrks

Here's something to ponder. Today I was talking with a mechanic who was fixing a large excavator whose entire right track assembly ripped from its mounting. It was held to the machine with only (8) 1-1/8" bolts which all had snapped. The bolts were sheared and could not be tapped out. What they found was a miniature version of an oxygen torch. I say miniature because the big version is 3" in diameter and 15' long. It's used to blow a drain hole in huge metal casting crucibles the size of a house.

The small version uses a chrome plated tube about an 1/8" in diameter that has 3 small copper rods inside. I didn't see it work but the mechanic said it has a pistol-like handle the chrome tube connects to. A pressurized line of oxygen connects to the pistol. 12v dc also connects to the pistol and a copper plate. The operator strikes a copper plate which starts the powerful flame. The oxygen blows molten metal out of the hole as it cuts. The chrome tube melts too. It cuts a hole just a bit larger than the tube. They cut three holes in the bolts and somehow twisted them out.

Another thing I forgot was we have what are called "cutting rods" for arc welders---solid carbon rods. I've used them with mixed results. Mostly the "cut" is very crappy looking---nothing like a good edge cut by an oxy/acet torch. But in a pinch they may prove useful. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-06 00:00:00 172867  earthwrks

Here's something to ponder. Today I was talking with a mechanic who was fixing a large excavator whose entire right track assembly ripped from its mounting. It was held to the machine with only (8) 1-1/8" bolts which all had snapped. The bolts were sheared and could not be tapped out. What they found was a miniature version of an oxygen torch. I say miniature because the big version is 3" in diameter and 15' long. It's used to blow a drain hole in huge metal casting crucibles the size of a house.

The small version uses a chrome plated tube about an 1/8" in diameter that has 3 small copper rods inside. I didn't see it work but the mechanic said it has a pistol-like handle the chrome tube connects to. A pressurized line of oxygen connects to the pistol. 12v dc also connects to the pistol and a copper plate. The operator strikes a copper plate which starts the powerful flame. The oxygen blows molten metal out of the hole as it cuts. The chrome tube melts too. It cuts a hole just a bit larger than the tube. They cut three holes in the bolts and somehow twisted them out.

Another thing I forgot was we have what are called "cutting rods" for arc welders---solid carbon rods. I've used them with mixed results. Mostly the "cut" is very crappy looking---nothing like a good edge cut by an oxy/acet torch. But in a pinch they may prove useful. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-06 00:00:00 172868  earthwrks

Here's something to ponder. Today I was talking with a mechanic who was fixing a large excavator whose entire right track assembly ripped from its mounting. It was held to the machine with only (8) 1-1/8" bolts which all had snapped. The bolts were sheared and could not be tapped out. What they found was a miniature version of an oxygen torch. I say miniature because the big version is 3" in diameter and 15' long. It's used to blow a drain hole in huge metal casting crucibles the size of a house.

The small version uses a chrome plated tube about an 1/8" in diameter that has 3 small copper rods inside. I didn't see it work but the mechanic said it has a pistol-like handle the chrome tube connects to. A pressurized line of oxygen connects to the pistol. 12v dc also connects to the pistol and a copper plate. The operator strikes a copper plate which starts the powerful flame. The oxygen blows molten metal out of the hole as it cuts. The chrome tube melts too. It cuts a hole just a bit larger than the tube. They cut three holes in the bolts and somehow twisted them out.

Another thing I forgot was we have what are called "cutting rods" for arc welders---solid carbon rods. I've used them with mixed results. Mostly the "cut" is very crappy looking---nothing like a good edge cut by an oxy/acet torch. But in a pinch they may prove useful. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-06 00:00:00 172869  earthwrks

Here's something to ponder. Today I was talking with a mechanic who was fixing a large excavator whose entire right track assembly ripped from its mounting. It was held to the machine with only (8) 1-1/8" bolts which all had snapped. The bolts were sheared and could not be tapped out. What they found was a miniature version of an oxygen torch. I say miniature because the big version is 3" in diameter and 15' long. It's used to blow a drain hole in huge metal casting crucibles the size of a house.

The small version uses a chrome plated tube about an 1/8" in diameter that has 3 small copper rods inside. I didn't see it work but the mechanic said it has a pistol-like handle the chrome tube connects to. A pressurized line of oxygen connects to the pistol. 12v dc also connects to the pistol and a copper plate. The operator strikes a copper plate which starts the powerful flame. The oxygen blows molten metal out of the hole as it cuts. The chrome tube melts too. It cuts a hole just a bit larger than the tube. They cut three holes in the bolts and somehow twisted them out.

Another thing I forgot was we have what are called "cutting rods" for arc welders---solid carbon rods. I've used them with mixed results. Mostly the "cut" is very crappy looking---nothing like a good edge cut by an oxy/acet torch. But in a pinch they may prove useful. ....
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Best way to free a seized pivot bolt / joint ??
2010-08-08 00:00:00 172901  drconsult


kt: Attempts were made at heating both the pin and the bushing on separate occasions. I am lucky in that I have a family friend that runs a small tool shop who can help with just about any machining project that I have. If the drilling damaged the bushing, he offered to machine a sleeve out of bronze, brass, steel, etc. and press it in for me.

hardwood: Fast heating of the bushing (before the pin heated up too much) or fast burning of the pin would certainly work. I'm a novice when it comes to torches and welding so I didn't even attempt it.

earthworks: You are talking about a cutting lance. It works similar to a plasma cutter except the lance is sacrificial and the plasma cutter using air and an electric arc. Both very handy tools that I wished I owned. I did just acquire a big 300amp arc welder so I'll have to pick up some solid carbon rods to go with it. A good tig welder is next purchase on the tool wish list as I often have delicate small jobs with stainless steel for dive gear.
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Best way to free a seized pivot bolt / joint ??
2010-08-08 00:00:00 172902  drconsult

FINAL SOLUTION:

Finally the pin is out and the loader is re-assembled. I don't have nice tools like a magnectic base mill, Oxygen lance, etc. so the solution involved simple tools and methods.

What I tried:

- Grease guns. High pressure 2 stage gun, "grease blaster", etc. Didn't work but this pin was severely seized. No doubt this would work on easier pivot pins.

- Penetrating oil. Used Liquid Wrench, Sea Foam's Deep Creep, WD40, etc. None of them worked on this job but the Deep Creep would work on not so severly stuck parts

- Heat. Several attempts at heating the pin and pushing together and separately combined with blows from a sledge hammer and operating the loader while holding the pin with the clevis pins (just snapped the clevis pins).

- Impact (air hammer and sledge). Drilling a small divot in the end of the pin helped preventing the air hammer from wandering. Repeated heavy blows with the sledge began to mushroom the head of the 1" diameter pin.

- Drilling (with loader assembled). Drilling through the pin with progessively larger bits will eventually get down to a thin wall on the pin which will be able to collapse and move with heavy blows. This will work for a bent pin but there is a high probability of damaging the bushing that is welded to the hydraulic cylinder.

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Best way to free a seized pivot bolt / joint ??
2010-08-08 00:00:00 172904  drconsult

FINAL SOLUION - part 2

One more thing I tried:

- After removing the cylinder from the tractor, I used a 20 ton press to try and push the remainder of the pin from the bushing. Maybe a bigger press would have produced a different result??

What finished the job:

- Cutting the pivot pin using a reciprocating saw allowed me to remove the entire hydraulic cylinder from the tractor. Good quality thin blades are required. Mine was not but if the pivot pin is also stuck in the frame, this will reduce the amount of force needed to get the two remaining pieces out after cutting the pivot pin.

- Soaking the ends with penetrating oil. While installed on the loader, there was no way to have penetrating oil sit on the sides. I'm sure that this made my hammer and chisel work a bit easier to start but the oil certainly didn't penetrate all the way through.

- Drilling with a drill press (A mill would work better). You will need a good set of large diameter bits (beyond 1/2" I used progressively larger silver and demming bits). Don't forget the Kutwell or similar lubrication / coolant when drilling though metal. With the entire cylinder well clamped and accruately centered on a good powerfull low speed drill press, I was able to drill almost all the pin out until a small bushing like part remained. Other than the pilot hole, I did not drill it all the way out. That gave me a "ledge" to hit with a blunt chisel or piece of round stock.

- Hammer and punch to knock it out. A small chisel an pin punch was used to collapse some of the walls of the pin from either end of the bushing. Finally I could knock it out with a piece of 3/4" round stock.

- Curved file and 1" round wire brush to clean it up. The curved file let me remove the remaining rust / debris and helped smooth out the pitting that was present in the bushing. Using a hand file will ensure that you don't oversize the bushing and end up with a sloppy pivot pin. The 1" diamter stainless wire brush cleaned the bushing and finished off the inner ID nice and smooth.


A HUGE THANKS go out to everyone who posted ideas. Should our paths ever cross in person, I'll buy you a beer!
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Best way to free a seized pivot bolt / joint ??
2010-08-18 00:00:00 173265  kthompson

Really appreciate your step by step follow up. Sorry it was so difficult but this was a great case in maintance has a real benefit.

Now hang around and help me and others with our needs. :) ....
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Best way to free a seized pivot bolt / joint ??
2010-08-27 00:00:00 173495  auerbach

I had a simpler solution for you. It involved a military proving ground and some depleted-uranium ordnance.... ....
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