Pulling seized pins

[steponmebbbboom]

Can we have a discussion about pulling pivot pins that are seized, stuck, rusted in place? We are in the process of removing the lift and crowd cylinders in a komatsu wa500 whose lubricator stopped working, and it has been a real struggle. we are not sure of what proper equipment to use, how to secure the loader arms safely, we have just been trying to beat the pins out with hammers and drifts and it's painfully slow and treacherous going.

How can we get the pins out of the base ends of the lift cylinders? The other ends of the pins are buried in the machine. How can we secure the loader arms properly so they dont come down on us when we get the pins out? How can we safely sling the cylinders so we can lift them out? Most importantly, how can we safely work in the loader arm area with so many trip/slip fall hazards and such heavy equipment to hold with our hands?

Pictures would be a huge help here. I don't want to go into work tomorrow with such high expectations of us when there is no one here who seems to know how to do this safely.

 

[Lee-online]

pulling seized pins is a pain. Depending on the pin and location we can press them out, pull them out with a press and rod or heat the surrounding area to expand it and drive the pin out. you can also heat the pin to shrink it, if that doesn't work burn a hole through it and then it should shrink.

Use stands, blocking to hold the loader arms in a safe position, use a crane, hoist to lift out heavy parts.

When working in an unstable position i like to sit down and work so i have use of both hands.

Here is a 980 i have all the cylinders off and the loader arms out of the way so i can work on the valve.

 

[dsichewski]

pulling seized pins is a pain. Depending on the pin and location we can press them out, pull them out with a press and rod or heat the surrounding area to expand it and drive the pin out. you can also heat the pin to shrink it, if that doesn't work burn a hole through it and then it should shrink.

Use stands, blocking to hold the loader arms in a safe position, use a crane, hoist to lift out heavy parts.

When working in an unstable position i like to sit down and work so i have use of both hands.

Here is a 980 i have all the cylinders off and the loader arms out of the way so i can work on the valve.

Not meaning to thread crap but just wondering do you work for Toromont Cat? that building looks familiar, I'm guessing Concord???

 

[2stickbill]

Safest,easiest and the best way is let somebody else do it.But if you really want to have fun.Get a loader that works in a fertilize plant and get greased about once a month.

 

[steponmebbbboom]

pulling seized pins is a pain. Depending on the pin and location we can press them out, pull them out with a press and rod or heat the surrounding area to expand it and drive the pin out.

hi,

can you expand on this a little? What kind of a press do you use, and how do you rig it to attach to the pin? We have been using a porta-power and boxsteel bars on the lift cylinder rod-ends to press them out against each other but have found that holding the rams and bars into position while another person pumps the hand lever is tiring and the long bar is unstable. Also the loader arms tend to flex outward before the pins give way. I feel we need to come up with a press/puller arrangement that acts directly on the pin area but i am encountering considerable resistance against spending any money on new equipment. Since this is a new job I can't really assert myself too much.

What size of a torch would you recommend for heating the yokes? My supervisor seems to think a regular #4 cutting torch will heat the area as quickly as a rosebud. I disagree.

 

[willie59]

If your a new guy on the job, and your super thinks a #4 cutting head can heat as quick as a rosebud, and your having difficulty pulling pins, walk and talk softly, your in a precarious position. You working in a situation that can fray nerves in an instant.

What kind of equipment do you have to work with? Do you have some type of crane and sufficient/safe rigging? Are you certain you have the pin in it's loose spot, not putting lifting or lowering pressure on the arms? Do the pins have threaded holes in the ends of them to fit a puller bolt? The more info you can give us without pics is a big help for advice.

 

[steponmebbbboom]

thanks, ive seen you on the forums a lot and have enjoyed your perspective, Thanks for weighing-in on this subject.

The machine is a Komatsu WA500, i think about 5 years old and less than 10K hours. The procedure is being done outdoors on coarse gravel about 4" diameter so watch your step. its about -10C out. 5cm of snow forecasted for Wednesday. I do have a guy helping me, but there is a language barrier and i am worried about his safety diligence. We have a regular #4 cutting torch, unlimited access to scrap, a couple of TEREX/FUCHS scrap handlers with grapples and mag attachments for hoisting, a couple of nylon slings and clevises, basic hand tools, nothing large.
the pins have tabs on the ends with 1/8NPT drillings so anything we use for pulling will have to be welded on. the pins are dry. The machine is covered in coal dust and mud, and some ice from attempts to powerwash it in the cold.
I have little experience working on machines this large as i come from a forklift/aerial lift/bobcat background but i have 12 years in the trade and three trade certificates so i know an unsafe situation when i see it, but my employer regards me as a junior tech and only being there one month im in no position to assert myself as its clear i wont be listened to. i have no savings and theres no other jobs in my area so i just have to tuck my head and get this done as safely as i can. ill listen closely to and apply any suggestions you can give me. it's much appreciated.

 

[Lee-online]

Well, working with what you have i would start off heating the loader frame around the pin. The pin is prolly seized at each end and not in the middle where the cylinder rod rotates on it. Try and get the area around the pin on both sides cherry red if possible by switching from one to the other. the faster you can do this the better so the heat doesn't transfer to the pin. While still heating, use a pin driver and a sledge to drive it out. Don't hit the edge of the pin and mushroom it.

As stated, make sure the loader is blocked and supported, put the lift cylinders in float to make sure the loader is secure and no load on the cylinder.

Welding on pins does not work well and is unsafe because they are hardened it is hard to get penetration.

 

[Iron Horse]

This is a huge and dangerous task for someone who is not confident on how to do it . Trying to utilise a bit of text from a screen into a real world job as dangerous as this is fraught with danger . If I where doing it myself I would do one side at a time so the loader frame is always held securely . Re install a smaller pin to hold the frame that can be pulled out easily once you are ready to lift the frame off . You probably have already Mushroomed the ends of the pins with the hammering enough to prevent them coming out . This will need to be ground off if you can get to it . Can you grind the tabs off the pins and press them out the other way ? If you can get a straight push between the pins you can use a 50 ton/tonne porta power between them with an solid drift bar an 8th smaller than the pin to give some pressure while you heat the pin bosses with a Pepper shaker tip .

 

[steponmebbbboom]

Welding on pins does not work well and is unsafe because they are hardened it is hard to get penetration.

Okay, so can we get back to your press arrangements? we should be able to get the rod-end pins out the way you describe here, but the base-end pins are buried in the frame and the back end of the pins are not accessible, so we are going to have to come up with something to pull them out with. if we are going to destroy the temper of the pins by welding we need to find another solution...

 

[steponmebbbboom]

heat the pin bosses with a Pepper shaker tip .

thats what Im trying to tell them

 

[Lee-online]

Its not that you destroy the temper, its when you load up the welded on nut with the press it normally rips off and the press goes flying.

Most Cat pins have a threaded hole into thread a puller rod into. add some spacer, a porta press and a ram and it should move. normally the limiting factor is the rods strength, 70tons.

The lower ones in a loader are some of the worst. that is when we just bronco them out.(carbon arc)

 

[Iron Horse]

Why do they need to be removed ? Are they worn badly or just tight in operation because of the lack of grease ? If the latter , you could drill a hole in the pin boss and fit a grease nipple so you can get some grease in there . Give them a work up and down and shoot some more in .

 

[steponmebbbboom]

the cylinders need to be removed so they can be sent out for reseal. the vendor will not warrant an in-frame reseal which was our first approach.

lee by bronco or carbon arc are you referring to thermite gouging? because we have the equipment to do that... but first i have to make the case for destroying the pins...

its when you load up the welded on nut with the press it normally rips off and the press goes flying

oh, wonderful. no, the holes in the pins aren't threaded....

 

[willie59]

stepboom, you still haven't described your decided method of supporting arms. Are you going to build a sturdy stand? You mentioned loaders and such for lifting, I trust your not going to use these to support the arms. If nothing else, I would roll the bucket all the way forward, place the bucket teeth on the ground, and just work on the arm cylinders. Once you get the arm cylinders off, then maybe you can remove the bucket cylinders. The bucket rolled forward with teeth in ground will support the arms. As for the rear pins, if they're a PITA to get out, compare the cost of 2 men labor hrs to remove them compared to lance them out quick and replace pins. Probably not much difference in cost, but considerable time saving. Just a few thoughts.

 

[Lee-online]

Carbon arc cutting is using the stick welder, oxy and using a consumable rod to burn through thick metal. Comes in very handy and is very easy to control and melt the pin out without damaging the cylinder or frame boss.

before doing that try shrinking the pin, heat the pin and get it as hot as you can, let cool and then try and knock it out.

I have seen thermite and would love to get a bunch to play with.

 

[steponmebbbboom]

hi, sorry for not mentioning. The bucket is removed. The ends of the loader arms are resting on the edge of an empty scrap bin, the kind that is carted around by luggers. this one is the same dimensions as the V-shaped bottom ones, but goes straight down on the side the loader arms are resting on it. I am concerned the bin may flip and bring the loader arms crashing down, but my supervisor disagrees. I have asked that the bin be at least weighted down with concrete blocks, with no success...

 

[Lee-online]

stepboom, you still haven't described your decided method of supporting arms. Are you going to build a sturdy stand? You mentioned loaders and such for lifting, I trust your not going to use these to support the arms. If nothing else, I would roll the bucket all the way forward, place the bucket teeth on the ground, and just work on the arm cylinders.

This is not a fail safe method of supporting the loader arms on some machines. The bucket doesn't go over center and when it drifts down it trys to and can slide or push the machine back. We had a tech almost get killed doing this because the parking brake did not hold. granted, outside the bucked will dig in the dirt and the machine should have a wheel chock.

Just a FYI.

 

[willie59]

This is not a fail safe method of supporting the loader arms on some machines. The bucket doesn't go over center and when it drifts down it trys to and can slide or push the machine back. We had a tech almost get killed doing this because the parking brake did not hold. granted, outside the bucked will dig in the dirt and the machine should have a wheel chock.

Just a FYI.

Yep, failed to mention track chocks Lee. Thanks.

 

[willie59]

hi, sorry for not mentioning. The bucket is removed. The ends of the loader arms are resting on the edge of an empty scrap bin, the kind that is carted around by luggers. this one is the same dimensions as the V-shaped bottom ones, but goes straight down on the side the loader arms are resting on it. I am concerned the bin may flip and bring the loader arms crashing down, but my supervisor disagrees. I have asked that the bin be at least weighted down with concrete blocks, with no success...

stepboom, sounds like you have a head on your shoulders. Just be careful and pay attention. You sound like your attentive enough to handle the deficiancies that arrive from the idiots that surround you.