Leaking Boom Cylinder

Stob

Member
Apr 5, 2013
37
4
8
VA
Hello, I have a L2550 with a LA 450 front end loader. Recently, one of the boom lift cylinders is dripping hydraulic oil quit a bit, A few drops wouldn't concern me, but this is getting worse. I've never pulled a cylinder apart to replace seals before. I found a parts diagram, one type of seal is shown in several places. How difficult is it to pull one apart and change seals?
 

Edke6bnl

Active member

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B7800 Kubota, case 1840 Skidsteer Ford 3500
Mar 31, 2022
186
88
28
Agua Dulce, California
I did my first on on a LA402 and it was pretty easy, one seal I had to put in very hot oil to stretch because it was rigid then it was oversize on the fitting I lightly put a hose clamp around it and it was fine in a half hour. take the gland nut loose while on the tractor( may have to get the tool) some use a wrench. I made the tool but it was not very tight nor does it have to be. Good luck
 

Henro

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May 24, 2019
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You got an answer to your question. But I would suggest you consider an alternative as well.

That would be to take the cylinder to a hydraulic shop and have them do it and be done with it. In my case, with my LA402 loader boom cylinders, a seal kit from Kubota was around $60 and the hydraulic shop charged me $100 each out the door for two cylinders. (Initially I had one leaking, but the second started leaking before I took the first off.)

You can save more money doing it yourself if you can source the needed seals aftermarket.

Just suggesting this as something to consider. Worked for me!
 
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TheOldHokie

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Hello, I have a L2550 with a LA 450 front end loader. Recently, one of the boom lift cylinders is dripping hydraulic oil quit a bit, A few drops wouldn't concern me, but this is getting worse. I've never pulled a cylinder apart to replace seals before. I found a parts diagram, one type of seal is shown in several places. How difficult is it to pull one apart and change seals?
Leaking around the shaft?

Dan
 

Edke6bnl

Active member

Equipment
B7800 Kubota, case 1840 Skidsteer Ford 3500
Mar 31, 2022
186
88
28
Agua Dulce, California
You got an answer to your question. But I would suggest you consider an alternative as well.

That would be to take the cylinder to a hydraulic shop and have them do it and be done with it. In my case, with my LA402 loader boom cylinders, a seal kit from Kubota was around $60 and the hydraulic shop charged me $100 each out the door for two cylinders. (Initially I had one leaking, but the second started leaking before I took the first off.)

You can save more money doing it yourself if you can source the needed seals aftermarket.

Just suggesting this as something to consider. Worked for me!
Thought about having it done BUT all the places around here wanted $200. I think I got the parts at Coleman.
 

Henro

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B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
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Thought about having it done BUT all the places around here wanted $200. I think I got the parts at Coleman.
For that price difference I would do it myself too. Maybe I just got lucky with the price difference being so small...
 

Stob

Member
Apr 5, 2013
37
4
8
VA
Thanks. I can see it takes a spanner to pull the "head" as they call it off, but there are seals shown on both ends of the head and piston, shown as part 070. The description says "kit seal". Do they come as a kit?
7554202310_s.png
 

ruger1980

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L4310 w/La682, L225
Oct 25, 2020
355
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CNY
All the seals needed to reseal the cylinder "should" come in the kit. It is a much easier job if you have a pin spanner and a seal install tool. Both are available online for a reasonable price. I like to have a ring compressor to compress the piston seals and help with installation as well.

That being said inspect your cylinder rods closely. Any nicks, rust or rough spots and you are only buying time with a reseal.
 

whitetiger

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there are seals shown on both ends of the head and piston, shown as part 070. The description says "kit seal". Do they come as a kit?
If you look at the parts picture that you posted, all 10 items that are labeled as "070" is included in the seal kit.
 

rbargeron

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Jul 6, 2015
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Hello, I have a L2550 with a LA 450 front end loader. Recently, one of the boom lift cylinders is dripping hydraulic oil quit a bit, A few drops wouldn't concern me, but this is getting worse. I've never pulled a cylinder apart to replace seals before. I found a parts diagram, one type of seal is shown in several places. How difficult is it to pull one apart and change seals?
On my LA450 loader the curl cylinders started leaking - they came apart easily using a pipe wrench on the outer gland nut. For inserting new seals, a tool like like this makes it simple - cylinder can stay connected on the tractor - just take out the pin and cylinder rod. I took my old seals to an auto & machinery supply store and they matched it up to generics.
 
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Jonny4523

Member

Equipment
L4310 HST
Nov 10, 2022
30
2
8
Lafayette, IN
Something else to consider is WHY it started leaking so bad to begin with.

I recently bought my tractor and 3 of the 4 cylinders on the FEL were leaking. I decided just to take in all 4 cylinders to have them rebuilt, as I assumed the 4th cylinder probably wasn't far behind the other 3. I made a few observations when removing the cylinders that surprised me as I really have no experience with hydraulics. The first was that other than the leaks, I did not remember having any perceived difference in FEL use between the 4. The second though was upon removal, there were dramatic differences in feel as far as how easy or how hard it was to manually push the shaft in and out of the cylinder tube. One or two of them seemed super easy, almost sloppy. One seemed 'normal'. And the other was completely frozen. I could not get that shaft to budget at all with just my hands. Visually, I could not tell a difference in the cylinder rods.

A few days after dropping off the cylinders, I get a call from the shop. Two of the 4 cylinders had bent rods. Point being, if I had replaced the seals myself on those two cylinders, they would have just taken out the new seals and started leaking again. So I'm glad I took it in so that they can checked straightness also (I assume they put it in a lathe between centers to check for straightness?). So if you do it yourself, at minimum I think I'd do a visual inspection looking for pitting/scaring/surface imperfections and then use a large level / straight edge to try to check how straight the shafts are.
 

Stob

Member
Apr 5, 2013
37
4
8
VA
Thanks for the info from all. Never thought a cylinder rod would bend under normal use. One issue I have is, looking at the parts diagrams, there are 3 different diagrams, appears to be of different serial numbers. Two of the diagrams use the same part number for the seals, but one has a different part number. I cannot make out the serial number on the sticker. The LA 450 is bright and clear but right below the serial number is missing. It's not a stamped metal plate, but a stick on. I'm not sure how to determine which seals to get. I assume if I order the parts I'm stuck with them if wrong. Maybe the local dealer can shed more info on this.
 

emac

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L3600, ZD1211, ZG20
Sep 13, 2021
15
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3
SC
I have an LA680 loader and have rebuilt all my cylinders over the years. I ran into the same issue with trying to get the right seals. I think I bought the wrong ones once but was able to return them. It isnt a hard job. Gets easier the more you do it! Its a good warm up for doing the steering box.

20210424_113822.jpg
 

lugbolt

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ZG127S-54
Oct 15, 2015
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hydraulic shop is always a good idea and sometimes less expensive than dealer. Unfortunately in my area there ain't any local shops, 50 miles is the closest, and it's in the worst possible part of town, thus I don't go there unless I absolutely have to. I rebuild them myself if at all possible. As long as they ain't seized, stuck, bent, etc, it's pretty easy.
 

Stob

Member
Apr 5, 2013
37
4
8
VA
I have an LA680 loader and have rebuilt all my cylinders over the years. I ran into the same issue with trying to get the right seals. I think I bought the wrong ones once but was able to return them. It isnt a hard job. Gets easier the more you do it! Its a good warm up for doing the steering box.

View attachment 93680
It's been a while since I posted my question. Had to delay the repair but the leak got so bad it forced it.
I ordered the seal kit from my local dealer, one was in stock at a different branch and it was in my hands in two days.

Went at it this morning. The pic above is just about exactly what I found, only mine had a self locking nut. All the old seals were dry rotted, they just broke apart licking them out. Didn't take long to replace the seals/o-rings. I coated the new seals with synthetic grease and it all went together easily. Back running and no leaks!
 
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fried1765

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Kubota L48 TLB, Ford 1920 FEL, Ford 8N, SCAG Liberty Z, Gravely Pro.
Nov 14, 2019
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Eastham, Ma
It's been a while since I posted my question. Had to delay the repair but the leak got so bad it forced it.
I ordered the seal kit from my local dealer, one was in stock at a different branch and it was in my hands in two days.

Went at it this morning. The pic above is just about exactly what I found, only mine had a self locking nut. All the old seals were dry rotted, they just broke apart licking them out. Didn't take long to replace the seals/o-rings. I coated the new seals with synthetic grease and it all went together easily. Back running and no leaks!
The simple answer to this leaking seal issue is in post #3 .

The other issue here is:
It is cold outside?
It is hot outside?
At 82, I just don't wanna do it!
 
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DeeDubz

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SVL75-2
Feb 18, 2023
4
0
1
So cal
Theres a guy on youtube called HOWIDIDIT. Hes a mechanic for skid steers. Mainly bobcats. But he goes into detail on how to rebuild a cylinder. Ive never done it but it doesn't look too hard.
 

Nicksacco

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Kubota L35 TLB
Sep 15, 2021
573
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Bahama, NC
I say if you have the tools and the time to go for it.
I've done cylinders and the hardest part is getting the darn gland off.
Actually, maybe the hardest part might be avoiding getting hydraulic oil all over yourself and your tractor!

I must confess I had the swing cylinders on my backhoe done at a shop.
I crawled around in dirt, grease and Lord knows what else to remove them so I could clean and paint the hoe. By the time I was done, I ran out of energy! Man are those little things heavy!

Yes, the hoe will get new hoses too. I don't want to go thru that mess again for a blown hose! :)

1680431710911.png
 
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