Stuck Pin? Hydralics Question

[timcote42]

Greetings all. I just bought a B7100 with a backhoe and a loader attachment, knowing full well that the swing cylindars on the backhoe were leaking an needed servicing. So today I did a bit of Thanksging tinkering and attempted to pull them out, but ran into a snag. Let me say up front that this is my first tractor, and while I once rebuilt a kubota engine (came out of my sailboat), I have no experience with hydralics.

Anyways, in trying to pull out the swing cylindars it seemed obvious that I should remove the pin that secures it at the proximal end (the part nearest to the operator). As shown in the photos, the pin was held by cotter pins above and below. I removed these cotter pins and was very surprised to find the pin totally immovable, on both sides no less! Stuck a screwdriver in the pin and couldn't rotate it, tried to lightly hammer it down, wouldn't budge, put a pipe wrench on the part sticking up from above and it wouldn't go.

I put in some WD40, took these pictures and saved the heavy ammo for response from this group. Assuming the WD40 doesn't miraculously loosen the pin, my next efforts would include using a gear puller or heat from a torch to bust the thing through. Given that both plates of the bracket with the holes through which the pin passes are welded to the rest of the hoe, it seems this pin MUST be extracted. Any advice before I get mean with this thing?

Tim

 

[Birdhunter1]

Is there pressure against the cylinder?
If there is it willprobably not move without ALOT of force and then will still be a booger to get out. Since it is off the tractor to get the pressure off the cylinder I would crack loose the hydraulic hoses and try to pry the cylinder back and forth a bit to relieve the pressure and the pin will probably fall out easily.
I would steer clear of using heat as pressure can build up in the cylinder and cause it to explode.

 

[MrJimi]

I am NO hydraulic expert by far but if you have any weight or pressure on this fitting. It will not come out
Jim

 

[charlz]

I have the same tractor and hoe... matter of fact from the missing paint and oil all over the place I had to look outside and make sure mine was still there

My swing cylinders also need to be repacked. When I looked at pulling the cylinders I was thinking it might be easier with it still mounted on the tractor. I am thinking your main 'swing pin' is worn and with the weight of the hoe resting on the boom your are getting some of that on the swing cylinder pins causing them to bind. If it was still on the tractor you might be able to use the boom or bucket to move up and down and find a 'sweet spot' where the pins will nearly fall out.

Try pushing down/lifting the end where it bolts to the loader and see if it makes any difference.

If you do have to drive the pins out it might be very difficult to get them back in.

Charles

 

[638]

If everything else fails, grind or cut off top end of the pin flush with the top bracket. Center punch and then drill into the end of the pin with increasing sizes of drill bits at least 1/4 the way through the pin. If the pin is 3/4" , you will want about a 1/2" hole, centered. Insert a short punch or maybe a 7/16" bolt in the hole just drilled. Use a heavy hammer and smack the c**p out of it. You may need to support the lower bracket to keep it from bending. The one thing that you don't want to do is mushroom out the end of the pin. Shoot some grease into that zerk fitting also.

ron

 

[TalonDancer]

You haven't said whether the swing cylinders on this BH actually work at all. Specifically, when the BH is attached to the tractor...

* do the swing cylinders swing the BH --- over the full range?
* do the pins rotate with the cylinder ends?
* do the cylinder ends rotate and the pins hold still?

IOW are the pins stuck in the cylinder bores, the frame or both.

FWIW if I were trying to free up a cylinder/pin I'd try to use the force of the tractor's hydraulics to do as much as possible before resorting to hammers, drills, pipe wrenches, etc. I don't see any grease in your pictures. Like 638 says, there's a zerk on that puppy -- use it If nothing else you'll find out if and where the grease comes out.

Talon Dancer

 

[timcote42]

Thank you all...what rapid service...only about 5 hours after posting and 5 messages. My wife say y'all are loosers and me too for being on the computer on Thanksgiving eve. But I am grateful, and that's what the day's about...

Okay, well I think the best advice is that it's likely bound up, and unwilling to move until I get the load off it. Indeed, the boom is off the ground. Yes, the swing cylindars did operate before I took it off the tractor, full left, full right, puddle of oil on the ground.

My next efforts will involve tipping the hoe on its side and trying to release the tenstion which no doubt is on the pin(s). Fortunately, I have a tractor to make pushing the metal around much easier. Would like to avoid the drilling the pin bit, but will if all else fails.

Tim

 

[TalonDancer]

...
My next efforts will involve tipping the hoe on its side and trying to release the tenstion which no doubt is on the pin(s). Fortunately, I have a tractor to make pushing the metal around much easier. Would like to avoid the drilling the pin bit, but will if all else fails....

From one looser to another

DON'T tip the hoe over! Hook it back up to the tractor. When the boom is pinned up (on level ground) there should be 0 force on the swing pins. They just rotate the hoe about the boom base axis. This position gives you the most leverage you will ever get at rotating the pins in the frame/cylinder bores. And it gives you the greastest ability to relieve any binding pressure on these pins. Yes even if you don't hook up the hydraulics.

FWIW I'd remove the other end first. Once they are off. You can manually center the boom and pin it straight. Then remove the hoe and get to the "proximal end".

Talon Dancer

 

[SPYDERLK]

Perhaps there is trapped pressure in the hyd lines and the two cylinders are pushing equally against one another. Tap the plug poppets and twiddle the levers. Repeat until no oil gushes out of the poppets.
larry

 

[LazyBoy]

When it's moved does the cylinder move on the pin or does the pin move? if the pin moves then the pin may be rusted into the cylinder, that could be very hard to get out. If it was mine I would start with some good penetrate like PB blaster and then put some kind of SOLID support under the lower cylinder support and that solid I-Beam like a adjustable screw jack or solid oak and then smack the **** out of it, it should move if you have solid support under it. You may want to try unhooking the other end first also.

 

[john_bud]

"Un-tipping" a hoe is not a fun job. Nor a particularly safe one either.

jb

 

[timcote42]

Well, for your continuing pleasure, here is the follow up (stage 1). I made sure the thing wasn't bound up with weights from elsewhere in the hoe. I took off the distal attachment of the cylindars. I drained all the oil. And I discovere that with fully mobile swing cylindars, these pins are quite firmly frozen inside the cylindar housing. I tried the "wack the **** out of it" advice and they barely moved. Heating with a torch was useless. Between a combination of the wacking and the use of a gear puller, I was able to get the pins down beneith the surface of the top bracket. However, I really would have wanted the pins to come up instead, but there was no way to exert wacks from below. I was hoping all this movement downward would crack everything loose, but no......

The next stage will require grinding off the pins so the cylindars can be extracted. Then I can set them on my arbor press and push out the remaining part of the pin. Have to go to Home Depo and get a metal-cutting wheel for my angle grinder as the bimetal blade on the Sawzall barely scratched the pin. Then need to buy a new pin. And finally, repack or replace these leaking swing cylindars.

I just bought the B7100 tractor/backhoe/loader. This buisness of trying to extract the leaky swing cylindars is my first real task with the thing. Will somebody please tell me all the jobs on this thing won't be such a pain?

Tim

 

[Dirthog]

If you have a torch heat up the back of the cyl and the pins should drive right out if you don't have them mushromed out to bad

 

[timcote42]

By the way, any guesses on what your standard 1"x4.25" pin will cost? They're drilled for cotter pins. Think they're heat-treated for hardnes? My guess is $20ea. Winning guess gets a cupie doll! Tim

 

[timcote42]

If you have a torch heat up the back of the cyl and the pins should drive right out if you don't have them mushromed out to bad

Well....the problem is the "drive it right out" part. It can't be driven down, would have to be pulled up. And I tried a propane torch, no such luck. Someday that "heat it up and it will break the crud" advice will work, so I keep trying, but so far I've only further frustrated myself with the technique....

 

[charlz]

I just bought the B7100 tractor/backhoe/loader. This buisness of trying to extract the leaky swing cylindars is my first real task with the thing. Will somebody please tell me all the jobs on this thing won't be such a pain?

Well, changing the clutch on mine was a bit of work you have to split the tractor in half.

It's funny though 'cause I just took the bucket off my hoe to re-work the worn holes/pins. While I was there I looked at my swing cylinder pins and they really did not look that stuck. Of course most of my pins look pretty sloppy!

I am interested to see how the repack goes cause mine leak all over the place and I was thinking about doing it this winter. I also want to make an 8 or 9 inch bucket for it. The 16" I have is just too big for putting in small water lines etc.

Charles

 

[SPYDERLK]

Well....the problem is the "drive it right out" part. It can't be driven down, would have to be pulled up. And I tried a propane torch, no such luck. Someday that "heat it up and it will break the crud" advice will work, so I keep trying, but so far I've only further frustrated myself with the technique....

From what you said earlier it sounds as tho you have a hardened pin. I cant understand why because theres no way that cly would strain a plain steel pin. On the off chance your saw blade was dull, try drilling a 3/16 hole as close to dead center as you can get. If you can drill it you can thread the hole and pull it out with a bolt. Try drilling it with a good quality HSS drill bit and let us know if it will penetrate.

larry​

 

[TalonDancer]

Well....the problem is the "drive it right out" part. It can't be driven down, would have to be pulled up. And I tried a propane torch, no such luck. Someday that "heat it up and it will break the crud" advice will work, so I keep trying, but so far I've only further frustrated myself with the technique....

AFAIK the idea behind using heat is to try to get two different pieces of metal to expand at different rates. In this case, to get the cylinder bore to expand without expanding the pin. That cylinder is a huge heat sink. You would need to heat it fairly evenly for a long time to get the whole end to "swell' enough to expand the bore. Meanwhile you would need to keep the pin cool, so it stayed the same size.

The heat required to expand the cylinder _bore_ would have burned (or at least discolored the paint) and the end of the cylinder would be bone dry.

BTW there is usually a very short time between when a bore expands and a pin/bolt (in direct contact) expands to re-close any gap. Applying heat is best done by two people - one apply the heat evenly and the other continuously tapping on the pin listening for any change in the sound indicating the gap opening -- then pounding the ____ out of the pin

Talon Dancer

 

[SPYDERLK]

AFAIK the idea behind using heat is to try to get two different pieces of metal to expand at different rates. In this case, to get the cylinder bore to expand without expanding the pin. That cylinder is a huge heat sink. You would need to heat it fairly evenly for a long time to get the whole end to "swell' enough to expand the bore. Meanwhile you would need to keep the pin cool, so it stayed the same size.

The heat required to expand the cylinder _bore_ would have burned (or at least discolored the paint) and the end of the cylinder would be bone dry.

BTW there is usually a very short time between when a bore expands and a pin/bolt (in direct contact) expands to re-close any gap. Applying heat is best done by two people - one apply the heat evenly and the other continuously tapping on the pin listening for any change in the sound indicating the gap opening -- then pounding the ____ out of the pin
Talon Dancer

This is good advice. If you dont have a really hi power torch tho you will not be able to get the needed temp difference between pin and bore. In that case, looking at it another way may be more effective. The rust that has that pin seized can probably be crushed leaving the pin looser. Heat the bore and pin as hot as you dare. Then spray a strong stream of water on the bore. It will shrink on the hot pin crushing the rust a little. Then spray on penetrating oil and let it cool completely. Then do as TalonDancer described. This assumes you cant drill and thread and pull it as I mentioned earlier, because that would avoid hammering on it and causing the end to mushroom.

larry​

 

[john_bud]

Yeah, your propane torch is outclassed by the amount of metal it has to heat. You need an O/A torch with a rosebud to get enough heat to do anything.

Once the pins are rusted in, they are a pain in the drain to get out. When you whacked it, you probably mushroomed the head of the pin and that compounds your problems. Always put something soft between the pin and the persuasion.

If you have the pins 1/2 way out, try heating the back of the cylinder up and twisting the pin with a pipe wrench.


Oh, let us know what the cost of the pins are. Most backhoe parts like pins and bushings are pretty dern spendy. Sometimes shockinly so.

jb