L3400/la463

00bushhog06

New member

Equipment
L3400DT/LA463, 3 bush hogs, 2 boxblades, tiller, 97 Ford F350 Dump, 18' trailer
Nov 26, 2019
9
0
0
OKATIE, SC
Bucket leaks down if left up with engine off. Lost some lifting power Tilt seems ok. Full of fluid and no leaks. Machine has 4200 hours. Bought new 2006 and all hours by me. I believe its in the valve assy. Thoughts?
 

Roadworthy

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Lifetime Member

Equipment
L2501 HST
Aug 17, 2019
1,649
525
113
Benton City, WA
If you see no external fluid you probably have internal leaks in one or more of your actuators or in the joystick control. You can probably rebuild the actuators yourself and they are the most likely failure point I suspect. I don't think you can rebuild the control without an actual hydraulic shop - tolerances are pretty precise.
 

Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
5,107
926
113
Williamstown Ontario Canada
Do not touch the valve! It is made with tolerances between the spools and their bores that you would not have the tools to measure these clearances unless you worked as a Metrologist. Clearances like 0.0005" and that is not five thousands of an inch!

Do this test on the cylinders and then you will know exactly what your problem is.

If you want to rule out the valve, swap bucket and lift arm hoses and see if the problem moves.

Block up bucket, disconnect the hoses and back the bucket off the supports so it is hanging on its own. If it sinks you know the valve is not involved.

Dave
 

Attachments

North Idaho Wolfman

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Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,295
4,853
113
Sandpoint, ID
This is just a second to Dave's comments:
It's not the valve, it's more likely an internal seal leak! ;)
 

00bushhog06

New member

Equipment
L3400DT/LA463, 3 bush hogs, 2 boxblades, tiller, 97 Ford F350 Dump, 18' trailer
Nov 26, 2019
9
0
0
OKATIE, SC
Thanks for the responses. I've pushed it hard for 14 years and had cylinders blow end seals and leak, but never an internal seal. But makes sense one could go. I'll run the test after the Holidays and see what it shows. Would one lift cylinder, leaking internally, rob pressure from the other side?

I have also noticed that the control handle seems sloppy. Thought it was wear in the control attachments it works in. That's been going on for a while, but the leak down and lift loss came on pretty suddenly.

I'll post when I do the test. Thanks again.
 

North Idaho Wolfman

Moderator
Staff member
Lifetime Member

Equipment
L3450DT-GST, Woods FEL, B7100 HSD, FEL, 60" SB, 743 Bobcat with V2203, and more
Jun 9, 2013
28,295
4,853
113
Sandpoint, ID
Would one lift cylinder, leaking internally, rob pressure from the other side?
Yes as they are plumbed in parallel so if you need to rebuild one, do both of them, or better yet all 4 at the same time. ;)
 

00bushhog06

New member

Equipment
L3400DT/LA463, 3 bush hogs, 2 boxblades, tiller, 97 Ford F350 Dump, 18' trailer
Nov 26, 2019
9
0
0
OKATIE, SC
Thanks, Wolfman. one side was rebuilt recently. I'll start with the older one for the test.
Hope everyone had a good holiday.
 

00bushhog06

New member

Equipment
L3400DT/LA463, 3 bush hogs, 2 boxblades, tiller, 97 Ford F350 Dump, 18' trailer
Nov 26, 2019
9
0
0
OKATIE, SC
Dave, Sorry for the delay in thanking you for the diagram. That will be a big help. I've worked on a lot of machinery including full overhaul of 365 HP Cat marine engines. Complete rookie on hydraulic systems. Thanks again.
 

00bushhog06

New member

Equipment
L3400DT/LA463, 3 bush hogs, 2 boxblades, tiller, 97 Ford F350 Dump, 18' trailer
Nov 26, 2019
9
0
0
OKATIE, SC
I did the quick test since I didn't have caps on hand to do full test. I blocked up the bucket and removed the retract hose on the recently (6 mos) rebuilt cylinder. Backed off the blocks and the bucket went down and pushed a weak stream out of the retract port. Reconnected it and repeated the same on the other side.
No discharge from the retract port.

I'm thinking my rebuild guy is going to get an opportunity for a REDO!

Thanks, Dave and Wolfman, for the very helpful info.

I hope you and your families have a Merry Christmas and a Happy and Prosperous New year!
 
Last edited:

00bushhog06

New member

Equipment
L3400DT/LA463, 3 bush hogs, 2 boxblades, tiller, 97 Ford F350 Dump, 18' trailer
Nov 26, 2019
9
0
0
OKATIE, SC
Success, thanks to great advice from Dave and Wolfman! After a less than coherent response from the guy that rebuilt the cylinder in August, I took it to a shop that has repaired cylinders for me in the past.
They repaired it and found that the piston seals had been installed incorrectly. They fixed it quickly and very reasonably.
I installed the cylinder yesterday and the system works quicker and stronger
than it has since the last repair.
Having never experienced an internal blow by leak, I would never have thought to look there, without your responses and expert advice.
Thanks again, and thanks to those who run this much needed forum.
Happy New Year to all!