LA480 - Boom Cylinder troubles

[CPo]

I'm in the process of disassembling the boom cylinder for rebuild to get rid of a hydraulic leak.

The head was an absolute beast to get off and I ended up mangling it with a pipe wrench. It eventually gave in and came off. But took a lot of leverage for a long time before it came away from the cylinder. Turns out that the last person who assembled this thing cross-threaded most of the threads. There are 2 good threads left, and 5 are stripped/mashed. The cylinder on the other boom arm has similar pipe wrench marks on it to what I just did to this one.

I really hope that the threads inside the cylinder haven't been mangled to match those on the head. I suspect that the cylinder is OK being that it is steel, while the head is aluminium.

Before disassembly, this cylinder was leaking from the shaft seal. The cylinder had been repainted and the paint sealed the head to the cylinder.

Given the condition of the head in the image below, would you:

1. Replace the seals, reassemble, keep an eye on it and hope for the best.
2. Use a thread file, try to repair the threads, replace the seals, reassemble, and hope for the best.
3. Find a local machine shop and get a quote to copy the head, replace the seals, etc.
4. Buy a replacement head from Kubota ($201.50), replace the seals, etc.
5. Other...

Looking forward to hearing your ideas.

 

[TheOldHokie]

I'm in the process of disassembling the boom cylinder for rebuild to get rid of a hydraulic leak.

The head was an absolute beast to get off and I ended up mangling it with a pipe wrench. It eventually gave in and came off. But took a lot of leverage for a long time before it came away from the cylinder. Turns out that the last person who assembled this thing cross-threaded most of the threads. There are 2 good threads left, and 5 are stripped/mashed. The cylinder on the other boom arm has similar pipe wrench marks on it to what I just did to this one.

I really hope that the threads inside the cylinder haven't been mangled to match those on the head. I suspect that the cylinder is OK being that it is steel, while the head is aluminium.

Before disassembly, this cylinder was leaking from the shaft seal. The cylinder had been repainted and the paint sealed the head to the cylinder.

Given the condition of the head in the image below, would you:

1. Replace the seals, reassemble, keep an eye on it and hope for the best.
2. Use a thread file, try to repair the threads, replace the seals, reassemble, and hope for the best.
3. Find a local machine shop and get a quote to copy the head, replace the seals, etc.
4. Buy a replacement head from Kubota ($201.50), replace the seals, etc.
5. Other...

Looking forward to hearing your ideas.

I would measure bore, stroke, retracted length and go shopping for two new cylinders. They dont have to be an exact match. Here is one possibility if it will fit in the loader arms.

1.75 in bore x 18 in stroke Loader Welded Hydraulic Cylinder | Magister Hydraulics

1.75 in bore x 18 in stroke loader double acting welded hydraulic cylinder with cross tube ends. Made for heavy-duty hydraulic equipment. It can be used for a variety of automotive hydraulic applications, construction equipment, agricultural machinery, forestry and logging, and mining equipment...

www.magisterhyd.com

Dan

 

[CPo]

I would measure bore, stroke, retracted length and go shopping for two new cylinders. They dont have to be an exact match. Here is one possibility if it will fit in the loader arms.

1.75 in bore x 18 in stroke Loader Welded Hydraulic Cylinder | Magister Hydraulics

1.75 in bore x 18 in stroke loader double acting welded hydraulic cylinder with cross tube ends. Made for heavy-duty hydraulic equipment. It can be used for a variety of automotive hydraulic applications, construction equipment, agricultural machinery, forestry and logging, and mining equipment...

www.magisterhyd.com

Dan

Someone on Reddit gave the same advice. IF I go this route, will I be able to reuse the Kubota hoses and "plumbing" hardware, or will I need to replace those as well? The combined cost of cylinder plus hardware make make replacing just the heads more appetizing.

 

[TheOldHokie]

Someone on Reddit gave the same advice. IF I go this route, will I be able to reuse the Kubota hoses and "plumbing" hardware, or will I need to replace those as well? The combined cost of cylinder plus hardware make make replacing just the heads more appetizing.

The threads on that cylinder are TOAST and will never be reliable.

As best I can tell the Kubota cylinderl has SAE-06 ports just like the Magister cylinder. You are looking at %400 plus tax. Thats a bargain.

The burning issue is will the Magister cylinder fit the mounting points on your loader. You have a dimensioned print for the the cylinder so should be easy to determine.

Dan

 

[CPo]

I measure the cylinder as 2" Bore, 20" Stroke, 27" Ret length.

Hmmm - Kubota sells replacement cylinders for $1100 CAD...

Princess Auto sells cylinders that are close (2" X 20" X 28") for $200

Is that one inch worth $900??

https://www.princessauto.com/en/2-in-bore-threaded-head-utility-cylinders/product/PA1000000430?skuId=8411209

 

[TheOldHokie]

I measure the cylinder as 2" Bore, 20" Stroke, 27" Ret length.

Hmmm - Kubota sells replacement cylinders for $1100 CAD...

Princess Auto sells cylinders that are close (2" X 20" X 28") for $200

Is that one inch worth $900??

https://www.princessauto.com/en/2-in-bore-threaded-head-utility-cylinders/product/PA1000000430?skuId=8411209

Kubota prices are absurd snd one inch in length is not likely to be meaningful.

But you need to be sure of your measurements and you must replace the cylinders in pairs. The manual for the LA482 says bore is 45mm (1.75") and stroke is 17.8".

Dan

 

[CPo]

Now you've got me wondering if these are original cylinders...

I measure 2" ID at the end of the thread, but if the threads take another 1/8" then maybe that 1-3/4" ID starts to make more sense. The stroke I measured with the cylinder torn apart, so I may be wrong on that one.

I'm thinking I'll get the Princess Auto cylinders, see if they fit, and go from there.

EDIT: I just noticed you are looking at the LA482. This is an LA480, so maybe that's where the difference is. I'll go hunting for a manual for the loader.

 

[TheOldHokie]

Now you've got me wondering if these are original cylinders...

I measure 2" ID at the end of the thread, but if the threads take another 1/8" then maybe that 1-3/4" ID starts to make more sense. The stroke I measured with the cylinder torn apart, so I may be wrong on that one.

I'm thinking I'll get the Princess A, see if " stroke fit, and go from there.

The LA482 manual is clesr 45mm (1.77] x 450mm (17.7). That would be a 1-3/4 x 18 cylinder.. A 20" stroke is going to be way too long.

Messicks says that OEM cylinder is used on LA480, LA481. and LA482.

Dan

 

[CPo]

Cool - the 18" size saves me a few bucks and its in stock too! Thanks!

 

[TheOldHokie]

Cool - the 18" size saves me a few bucks and its in stock too! Thanks!

Have you confirmed the width at the pins will fit inside the loader mounts?

Dan

 

[Russell King]

@TheOldHokie
I am thinking you missed the comment in post #7 since you are referring to. the la482. But maybe you just mis-typed??

I am just confused if the cylinders are correct or not correct?

 

[TheOldHokie]

@TheOldHokie
I am thinking you missed the comment in post #7 since you are referring to. the la482. But maybe you just mis-typed??

I am just confused if the cylinders are correct or not correct?

I did not miss the comment but I think you missed this one


The LA482 manual is clesr 45mm (1.77] x 450mm (17.7). That would be a 1-3/4 x 18 cylinder.. A 20" stroke is going to be way too long.

Messicks says that OEM cylinder is used on LA480, LA481. and LA482.

Plus about a dozen others

Dan