Quickest and Favorite Methods for Aligning and Installing Attachment Pins

Hi Everyone,

I am new to Heavy Equipment Forums and very happy to have discovered a community of Heavy Equipment mechanics and operators. I am a pretty new and green service technician who works on a wide range of equipment, the largest source of equipment being Volvo. For only having been in the job for 8 months, I have learned and dealt with all sorts of projects, although I still bump my head in situations quite often.

Cutting to the chase, I was wondering all of your opinions on the best/fastest methods for aligning pins. We attach everything from buckets to pulverizers. We are required to attach and remove a lot of hammers, planers, brooms/brushes, shears....The list goes on.

Everyone seems to have their preferred method at work. Most people align by eyeing out the attachment holes with the stick holes and driving pins in. Then curling the H link to align for the rear pin. This is all done with attachment on ground. Once aligned, pins are drove in. Some other co-workers do it differently.

We are always on timed work orders and obviously some attachments are much harder than others to align and drive pins through. I'd really like to become more proficient and faster at this and always use the best approach. All inputs will be greatly appreciated.

Thanks a lot in advance guys. As a newer tech, I am sure I will have lots of future posts and inquiries but will also offer any help I can with anyone.

Before we had couplers, I was very "experienced" in changing buckets. Only real trick I liked was after getting the hinge pin in, if you raised the boom a couple inches so the bucket could hang freely, all you needed was to get the h-link close and you could rock the bucket into perfect alignment and push the linkage pin in by hand. Worked on hoes as big as a 400. Oh, and keep your feet out from under the bucket.

Trying to align the stick-bucket pin, especially on rough ground can be a lesson in frustration, so don't even try. Do this instead;

• Roughly align the stick and bucket bore.
• Slide through a length of suitable pipe. I've got a length of 2" dia with a 3/8" wall thickness for the job.
• Pick up the bucket so it's clear of the ground.
• Line up the H link with its bore and crash the pin through. Easy now that everything is swinging free.
• Manupulate the stick and bucket cylinders to get to the sweet spot where the bucket is hanging from the H link and the stick-bucket bores are in line.
• Remove your pipe and insert the pin.

This works well for machines up to about the 50T class. Bigger than that and it all starts to get a bit high off the ground so you need to find something to stand on and a crane to lift the pins, but the method still works.

Never had a lot of work on excavators but did have I believe it was a 350 Cat with an extra long stick on it that they used to clean out settling ponds. That one was "fun" as it was hard to move the end of the stick less than an inch at a time in any direction. Just needed to be patient and lucky! I believe sometimes we actually would use a small crane to position the bucket and just let the stick stay stationary.

Most of what I worked on was front end loaders. On those always liked having to remove the tilt linkage first then raise up the boom to let the bucket tip over then set down on cutting edge and top guard. This makes the boom pins easy to get to right up high instead of trying to stand on your head. Reinstall the same way but in reverse. position bucket flipped full forward so you can easily see the boom pins. Once they are in set the cutting edge on some wood and back up machine with hoist in float and roll bucket to level position then work on the pin(s) for the tilt linkage.

One day I was to the point working on a WA600 Komatsu loader where it was time to install the bucket and of course no help in site so I took loader out of the shop with two heavy pins positioned loader arms close to the lower pin holes in bucket. Slipped the pins in and raised bucket. Carried it in to the shop, like doing this on a smooth level area makes it much easier. Having the bucket hanging by the boom pin holes it was already close to being lined up. Set bucket down and eyeballed the alignment from the cab then got out and determined how much I was off by getting out and looking at it up close. It did take a couple times in and out of the cab! Those pins went in with only a few easy taps from a 10 pound hammer. Flipped bucket back and used small floor crane to hold up the tilt link and after a few tries got those holes lined up and slipped that pin in.

I have seen times when boss would be there for a sides the guy in the loader there would 3 or 4 guys running around the bucket swinging 20 pound hammers trying to get pins to go in misaligned holes and it would take twice as long. Point being take time to line things up and job will go much faster in the long run.

Forgot one or two important points. Clean pins and holes before starting and test fit them in bores to be sure someone has not buggered them up trying to force them in or out in the past. A minute or two with a file or die grinder up front can make the job go much faster!

I agree with Cmark, put an undersize bar through the dipper bucket hole, pick it off the ground and fit the correct pin to the link side, then remove the undersize bar and fit proper pin. Much easier with it suspended off the ground.
Alternatively tell the cheapskates to get into the 21st century and fit a quick hitch. If they do a long term bulk shifting job they can always remove it if they are not going to be changing buckets/attachments for a long time.
Graham

When installing buckets, use a safely rated strap/chain and lift the bucket from the lifting ring on back of the bucket. Raise the boom high enough to allow the bucket to fit under the boom. that way you have the ability to align th bucket to stationary boom/arm. With that pin in place, the link pin is real easy to install. Find the lifting point balance on any attachment and it will be just as easy. It has worked for me up to 1200 sized Hitachi excavators. You get to figure it outeal quick when you put way to many on by yourelf.

Underside pipe or prybar through the main bore just like everyone else has said, and send the H-link pin through. That isn't too bad. Don't get me started mounting munchers and concrete crushers though. Ugh.

Just to be different, try putting undersize bar through H first. Then dangle bucket from H and find spot where dipper is lined up, slide dipper pin through. Very easy to remove load off undersize bar after that, by simply crowding until bucket "hesitates", at this point the H is aligned. I've found this way easier when putting shims in there on the dipper pin, too.

Years ago at a minesite I line bored a bucket of a 160 ton Demag. Big machine for the time. The fitters called up a grader and had it grade a level pad. Walked the digger onto it and set the bucket iin front of it. I think there were 2 pivot pins and 1 crowd pin. They had a litttle IT28 to push the bucket around a bit.

Cmark said:

Trying to align the stick-bucket pin, especially on rough ground can be a lesson in frustration, so don't even try. Do this instead;

• Roughly align the stick and bucket bore.
• Slide through a length of suitable pipe. I've got a length of 2" dia with a 3/8" wall thickness for the job.
• Pick up the bucket so it's clear of the ground.
• Line up the H link with its bore and crash the pin through. Easy now that everything is swinging free.
• Manupulate the stick and bucket cylinders to get to the sweet spot where the bucket is hanging from the H link and the stick-bucket bores are in line.
• Remove your pipe and insert the pin.

This works well for machines up to about the 50T class. Bigger than that and it all starts to get a bit high off the ground so you need to find something to stand on and a crane to lift the pins, but the method still works.

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Our mechanic at the shop taught me this way to change my hoe buckets at work! I can literally change buckets on a 330c hoe in 12 minutes. armed with nothing but 2 wrenches a pc of pipe and a pry bar. He even scribed cheater marks on the side of the buckets that gets lineup done almost instantly! I once saw him send a hoe back to Cat because he saw hammer dings in a new pin that had just came of there for a rebush....

bvfdfire said:

I once saw him send a hoe back to Cat because he saw hammer dings in a new pin that had just came of there for a rebush....

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I never liked seeing the way some guys would whale away at a pin to put it in instead of taking a couple minutes to get things lined up first. That's why I always cleaned pins and bores and test fit them in advance.

Maybe the worst pin I came across to install is the one at the position the arrow points to in this picture:


It has four separate links plus the tilt cylinder all held together with one pin. Watched a couple "professionals" do the job over the years. First being the Cat dealer guy. He took a couple pieces of flat stock and welded the two right and two left links to their mates then pulled pin. After replacing cylinder proceeded to hammer the pin in and then cut off the flat sock pieces and ground the links smooth and painted. Another time a sub-contractor mechanic, who had been a dealer mechanic before going out on his own. I believe he also used the weld on straps approach but to reinstall pin had me ram it in with the end of the fork on our fork truck while he whaled at it with a sledge.

We the spring before I retired I had the opportunity to replace the tilt cylinder myself. Being the lazy type who does not like spending lots of time swinging a 10 pound hammer I took a different approach. Used a small chain jack to position right side rear link close to where it needed to be when attaching to cylinder the used small overhead crane to position the forward link and slid the pin through those. Next picked up the rod end of the tilt cylinder and got it aligned with the right side links and used dead blow hammer to get pin started in to the tilt ram. Now the easy part, I had previously had the shops welder, he was handy and a better welder than me, weld a short metric bolt that threaded in to the hole in the pin that the retainer uses to a piece of 3/4 all thread. Screwed this "tool" in to the end of pin and using an old bushing and plate with a 3/4 hole in it spun a nut on the all thread. One hand on a 1 1/8 wrench pulled the pin in and out of the tilt ram enough to hold the front link. Next used a small chain jack to hold the rear link in position then used the old bushing and plate to pull the pin all the way home. Other than a few taps with dead blow hammer this was all done without any major beating of anything. Total time was probably half that of what I saw others take to do the same thing and done more or less single handed where the others had at least two people involved much of the time. Only cost was for a couple feet of 3/4 all thread and an odd, maybe 24 mm, bolt that was in bolt bin already. And add in the safety factor of not having someone standing on a ladder swinging a hammer with metal chips flying off!

"Being the lazy type who does not like spending lots of time swinging a 10 pound hammer I took a different approach."


NOW THATS FUNNY....after being here for a while and reading many of Kshansens replies the last thing I would say you are is lazy....smarter than the average trained bear seems better...

This is all really awesome and informative information, Thanks a ton guys. We have plenty of quick couplers but we basically have to cater to any customer specific request per attachment so a lot of times we are unable to use a machine with quick coupler and attachment has to be pinned directly. I've always wondered about using a bar to hold the stick bore in place through an attachment but was always concerned it might damage the bore itself since it is not an exact fit. That is the biggest problem with being a rookie, you are always worried about screwing something up haha. Also exactly how far off the ground are you guys keeping the bucket/attachment off the ground to perform this method? I am assuming to is just enough so that the attachment can be manipulated by hand to drive in the link pin?

VTECH20240 said:

Also exactly how far off the ground are you guys keeping the bucket/attachment off the ground to perform this method? I am assuming to is just enough so that the attachment can be manipulated by hand to drive in the link pin?

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Yes. Also, if things are lined up properly, you shouldn't have to "drive" the pins in. You might need some assistance on any pin bigger than 3½" (90 mm), anything smaller than that you should be able to push it in by hand, unless it's winter and the grease is stiff.

One more little thing I do when installing a bucket where I have someone in machine operating controls. First off I am very selective about who I would let be in the cab, always like going home with as many fingers and limbs I had in the morning!

I always told them to watch me and move levers in the direction I point, DO NOT worry about which way cylinder rams or linkage moves! This way I feel I had more control over the machine and did not have to hope the two of us were thinking the same thing. Some designs have rods or linkages going in the opposite direction the levers in cab move and it can add a slight bit of confusion, not something I want when I'm working in a tight spot!

Tags said:

"Being the lazy type who does not like spending lots of time swinging a 10 pound hammer I took a different approach."


NOW THATS FUNNY....after being here for a while and reading many of Kshansens replies the last thing I would say you are is lazy....smarter than the average trained bear seems better...

Click to expand...

All good Mechanics are conservative of there energy(; Make machines work for you not against you

Shimmy1 said:

Before we had couplers, I was very "experienced" in changing buckets. Only real trick I liked was after getting the hinge pin in, if you raised the boom a couple inches so the bucket could hang freely, all you needed was to get the h-link close and you could rock the bucket into perfect alignment and push the linkage pin in by hand. Worked on hoes as big as a 400. Oh, and keep your feet out from under the bucket.

Click to expand...

That's the way I do it, but first makes sure you are on flat ground. If not make a flat spot with the bucket your taking off for the one you're putting on to sit on. It has to be perfect so take your time. If the machine don't have a bucket well then use the undersized pipe trick.

I only had two machines that I've had hell getting attachments on using these technique. One had something bent and it would take our mechanic 3 hours of beating the pin to go in. The other one was in machine that the pins were made to the little bit too big and you just had the beat them in there.

I never clean the old grease off unless it contaminated. That way I don't have to put a tube of grease in that pin before it's ready to go to work.