JD410 hydraulic problem

Yj90

New User
Hello all, I just joined this forum based on a recommendation from a member at heavy equipment forum. I have a problem with my backhoe that's been really hard to figure out so far. Thank you in advance for any input. I'm running out of resources and need this machine running, so hear it goes! The machine has slow/weak hydraulics when hot but everything works/moves good when cold(especially the loader). The other issue is it slips in higher gears, low range it pulls ok but, in high range forget it, sits and slips under its own weight. So far, I've drained and refilled the transmission. Got a set of gauges tested the reverser pressure at 100psi which I believe is about 50 to 60 psi low. I have not been able to test the main pump pressure because my fitting doesn't fit, heading to hydraulic shop tomorrow for the correct fitting. What I understand is the problems may or may not be connected. I am also under the impression, that if pump pressure is low, it doesn't mean the pump is bad(must be flow tested to know?)not sure what to check where first, then what to check next, and so on. Sorry about the lengthy first post, trying to give as much info as I can.

Thank you in advance again
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The stand-by pressure adjustment won't have a big
effect on slow hydraulics. Need more info. You say
it slows down. Does it just start getting slow but
things move slow? Or does it get slow, and jerk and
make chattering noises?
 
Things just get slow, but stay smooth. If I'm using the loader it has no power and the hoe keeps drifting down(I'm continuously pulling it back up off the ground. In the first ten minutes of running the machine taking a full scoop of dirt is no issue after maybe 20mins, half scope is a challenge.
 
It would seem to me that there is a problem with the charge pressure/flow when it's hot. Probably a small leak that is not so noticeable when it's cold but as the oil thins as it heats... the loss becomes greater. The only way you're going to find it is by pressure and flow testing when it's cold vs hot and isolating systems to find where it's going. It could also have main pump problems or high pressure leaks but given you have a problem with the reverser clutches I'd say it's more likely on the low pressure side.
You can/could buy the manual online from Deere in PDF format for not a whole great pile of money...


Rod
 
Thanks for the reply, I do have a manual for this machine. Not sure where to start with this issue, my guess would be to test transmission pump pressure at the hydro pump port? I was told by a equipment mechanic, that the transmission pumps rarely if ever go bad, that they are gear pumps, and if they move fluid there probably fine. Not sure how sound of advice that is?
 
I don't know how durable the transmission pumps are on those machines specifically. Gear pumps do go bad tho. It's a few years since I looked at a 410. I remember that there's a bunch of regulating valves, 2-3 filters, a couple of accumulators etc that all play into that system. IIRC, the reverser and brakes both take their supply pressure from the charge circuit... mabey not the brakes but certainly the reverser..
So there's an opportunity for a leak in those circuits that will bleed the charge flow/pressure to the main pump. If that supply is weak then you get into shuddering hydraulics on the main circuits as the main pump cavitates.
Now... if you simply have slow/smooth and/or weak main hydraulics and NO shudders... then I'd probably be looking at the stroke control valve on the main pump or the system relief valve...
Also check the main strainer for the charge pump... you may find a load of brake material in there, etc.


Rod
 
When I inspected the screen, it was fairly clean. I did find this in there! No idea where that's from. I also noticed the brakes creep down to the floor if you hold them.
 
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If everything gets slow but it runs smoothly without
jerking or making chattering noises - the
transmission pump is not going to be the problem.
I'd be inclined to suspect a very worn main pump.
Worn transmission pump would result in the main pump
starving for oil, and jerking and chattering.
 
Do you think Deere can test the pump for me if I remove it? Is it worth me checking output pressure cold compared to hot? Finally, is it likely the drive issue is related to the hydraulic problem?

Thank you for your help, you are one of two guys I was told could help me figure this out. Just don't have the extra coin to pay someone to fix this machine.
 
If I was working on it -I just remove a few pistons
from the pump and inspect them. If they are very
worn and scored - you know the pump is worn out.
Same wit the piston-springs. No need to take them
all out. Generally speaking, if one is worn - they
all will be worn.
 

Sounds good, I'll check it out. They can be accessed from the large hex nuts that circle the pump?
 
Sounds like several problems.

The hoe constantly dropping down I'd be repacking the lift cylinder on it. Or at least take a hose off and test to see if the oil bypasses the packings first. It could be bad lift checks or valve spool ? But packings are a normal wear item.
 
(quoted from post at 05:42:57 08/01/14) Sounds like several problems.

The hoe constantly dropping down I'd be repacking the lift cylinder on it. Or at least take a hose off and test to see if the oil bypasses the packings first. It could be bad lift checks or valve spool ? But packings are a normal wear item.

I did notice a hydraulic leak from the top of the spool where the control lever goes through. If the pump is my issue, I'll move on to that next.
 
Yes. 1 1/4 or 1 1/8" socket as I recall. When you
remove a cap, there will be a spring and a piston
that pulls out.
 
(quoted from post at 13:15:03 08/01/14) Yes. 1 1/4 or 1 1/8" socket as I recall. When you
remove a cap, there will be a spring and a piston
that pulls out.

Okay, gonna tackle it tonight. Are the pumps easy to rebuild or is it a reman item?
 
(quoted from post at 13:15:03 08/01/14) Yes. 1 1/4 or 1 1/8" socket as I recall. When you
remove a cap, there will be a spring and a piston
that pulls out.

Seems like light scoring, can catch some with a fingernail.
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From what I can see those pistons look in
excellent condition.

Pump isn't hard to repair if you use the book.
Other then the small parts that are in the
control-valve housing (that comes off with four
bolts) the rest is pretty simple. Take out all
the pistons and springs. The before taking it all
apart - put a dial indicator on the pump shaft.
Measure end play. You want it to be .002". You
have to ADD shims to tighten it. So whatever you
measure in excess of .002" - you need to order
extra shims to tighten it. If it reads .012" then
you must order a .010" shim and install it when
you have the pump apart.
When you take off the bolt-housing - and take out
all the pistons and springs - the shaft just pulls
out. Pump will have 8 inlet valves and 8 outlet
valves, along with 8 pistons and springs.
The one thing that needs to be checked carefully
is the stroke control valve and seat in that four-
bolt housing. It is a major wear item. If can stop
the pump from working entirely if worn.
 
I'm taking it you feel I should still remove the pump and overhaul it? Should I remove and inspect the stroke control valve before pulling the pump?
 
I was running the machine to get a better idea of what it is and is not doing. It took about a 1/2 hour before the hyd. Functions slowed down. The hoe never really seemed all that slow or weak. I can lift the rear of the machine off the ground, maybe a little slow still has some power though. I did notice when everything was at its worst, if I want to lift the rear of the machine the hoe would push back abruptly then move in the controlled direction. The loader on the other hand is very slow to raise power down seemed kinda fast, I can lift the front of the tractor with it being very slow. I took a temp. Reading of the pump at 150 degrees and all cylinders were around 110 to 120. I still need to remove the stroke control valve. Is there any where else I should check?
 

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