JD 2850 Loss of Hydraulics

britcivic

Member
Livestock Farmer
Location
North Wales
So far the intermittent problem has not come back.....fingers crossed..

I have a question about plumbing in the hydraulic motor for the winch.
I was about to pinch the transmission bowl with return fitting, pipes and closed centre spool off my 1140 in order to do so.
BUT having studied the 2850- it has two double acting spools with the return plumbed through a separate canister filter then straight back to the hydraulic reservoir above the pump - surely I can just run the motor off the spool since it will be pumping straight back to the resevoir? - or am I mistaken?
 

Hesston4860s

Member
Location
Nr Lincoln
So far the intermittent problem has not come back.....fingers crossed..

I have a question about plumbing in the hydraulic motor for the winch.
I was about to pinch the transmission bowl with return fitting, pipes and closed centre spool off my 1140 in order to do so.
BUT having studied the 2850- it has two double acting spools with the return plumbed through a separate canister filter then straight back to the hydraulic reservoir above the pump - surely I can just run the motor off the spool since it will be pumping straight back to the resevoir? - or am I mistaken?

your mistaken !.
 

jd6820

Moderator
Arable Farmer
Can you elaborate on that....? The return pipework definitely looks like it goes straight back to the hydraulic reservoir..
Not technically back to the reservoir as I recall, but to the pump inlet. Maybe the use of this filter as a return path isn't advised as it has various flow restrictions hence the recommended route via the filter bowl on the transmission filter.
 

Tractortech

Member
Location
Cumbria
Your 2850 will have double acting closed centre spools. No need to rob them off the 1140.. I thought I saw a filter bowl on the well know auction site. However, I can't find it now..
As for the motor.. Some motors don't like back pressure and blow the shaft seal out.
You are indeed correct that the return oil from the spools should pass through the spin on filter and back to the lube circuit which supplies the front pump. Unfortunately, many such tractors had the ball, spring and valve seat removed from the spool base. A single acting ram struggled to overcome the back pressure of 155 psi. Little tipping trailers and post drivers had problems.
So, if it's in place and your motor is OK with back presure. Return into the SCV Coupler. That way, the pump drives the motor, returning oil goes directly back to the hydraulic pump.. Back to the filter bowl has the same effect..
 

britcivic

Member
Livestock Farmer
Location
North Wales
Thanks so much - this could save me a few hours rushed work to get this ready for a job tomorrow. As JD 6820 said it doesn't go to the reservoir, but to the pump inlet (- it's tricky to follow the pipes where they pass beneath the radiator - and to follow the flow diagram in the manual!) .

I reeled 150 foot of new winch wire on yesterday, which is about 5mins constant running of the motor (slow but strong, this winch). All seemed fine, no dodgy noises from front pump, so I figured it was plumbed as I thought. Thanks for confirming that Tractortech - much appreciated.

Just want to change the rest of the rubber pipes in the cooler circuit today if they get here in time from Nick Young...

If I take the caps off the spool bases I should see if the ball and springs are still there, yes?

The only problem I have left then is that 2 spools is not enough, - ultimately I'll have to plumb in a seperate closed centre block like I have on the 1140.. I'll pipe this back to the filter bowl (also coming 2nd hand from Nick Young)..

I'll have to dig out the motor specs and see if there's anything relating to back pressure...
 

Hesston4860s

Member
Location
Nr Lincoln
Even if you pipe to the filter bowl you’ll still get 150 ish psi back pressure, there really is no good way of having a true free flow return on a 50 series.
I went though all this when I had my Superchaser on my 3050 !.
 

Tractortech

Member
Location
Cumbria
Items 12, 13, 14 & 15. It's all in the bottom section..
Screenshot_20200527-130504.png
 

britcivic

Member
Livestock Farmer
Location
North Wales
So the tractor has been doing a bit of work for me now, with no repeat of the complete loss of hydraulics thank god...

The one repeatable issue I have is that once warm the lift arms will slowly drop when it's idling, and the oil pressure light will come on (Hi Lo still works though). If I give a bit of revs they'll pick back up and when it comes back down to idle they stay up ok.

The lift arms will drop straight away when I stop the engine every time.

Is this just the main seals in the rockshaft, or do I suspect the pump too? (destroke valve from what I've been reading?)

The pressure is 180 bar on the gauge on my crane spool block when I start from cold, and the hydraulics seem plenty strong enough.

BTW The winch is working fine on the spools....
 
So the tractor has been doing a bit of work for me now, with no repeat of the complete loss of hydraulics thank god...

The one repeatable issue I have is that once warm the lift arms will slowly drop when it's idling, and the oil pressure light will come on (Hi Lo still works though). If I give a bit of revs they'll pick back up and when it comes back down to idle they stay up ok.

The lift arms will drop straight away when I stop the engine every time.

Is this just the main seals in the rockshaft, or do I suspect the pump too? (destroke valve from what I've been reading?)

The pressure is 180 bar on the gauge on my crane spool block when I start from cold, and the hydraulics seem plenty strong enough.

BTW The winch is working fine on the spools....
sounds like rockshaft lift seals
 

Tractortech

Member
Location
Cumbria
Is the low pressure oil light only on with the Hi-Lo in high or all the time at tickover??
This light is for the transmission oil pressure. With no or low transmission oil pressure there is no oil supply to the high pressure pump. The rockshaft seals and / or rockshaft valve seals must be leaking causing the arms to drop. There is some adjustment of the valves when you put seals in..
 

Geovr

Member
Mixed Farmer
Hi.
Does anyone knows who is the hydraulic oil flow at the output of quick couplers of a JD2850 tractor with a 23cm3 pump???? All hydraylic works fine except a hydraylic motor that when is connected to quick couplers it runs with lower rpm.
Thank u
 

Geovr

Member
Mixed Farmer
Hi.
Maybe i must edit my previous post.
So... Does anyone knows how much is the hydraulic oil flow (lt/min) at the output of quick couplers of a JD2850 tractor with a 23cm3 pump ??
 

Tractortech

Member
Location
Cumbria
Hi.
Maybe i must edit my previous post.
So... Does anyone knows how much is the hydraulic oil flow (lt/min) at the output of quick couplers of a JD2850 tractor with a 23cm3 pump ??
It depends how fast the engine is running..
However, I'd start a new thread of your own, with a good description of your problem..
 

Geovr

Member
Mixed Farmer
It depends how fast the engine is running..
However, I'd start a new thread of your own, with a good description of your problem..

Thank u for reply.
Yes, i forgot to write about rpm.
I am interesting for oil flow at 1800 ... 2000 rpm.
I use a Hydraulic motor MP400 and it runs with 60rpm at 2000 engine rpm. So if calculate 400ml x 60 rpm gives 24 lt/min oil flow that its very low for 23cm3 pump. I am afraid if double acting selective control valve reduces the flow ?? Also i don't know if there is any other valve that reduce the oil flow
at the output of quick couplers.

Regards
 

tonkee

Member
Mixed Farmer
  1. Check the Hydraulic System: Ensure the hydraulic oil level is normal, there are no leaks, and the condition of the oil is good. Inspect the hydraulic system's lines and connections for wear, cracks, or looseness.
  2. Brake System Inspection: Examine the hydraulic part of the brake system, including the brake fluid reservoir, pipes, and brake pump. Check the condition of the brake fluid and inspect the wear on the brake pads and discs.
  3. Focus on the Cooling System: Make sure the engine cooling system is functioning properly. Overheating can lead to hydraulic system failures.
 

Geovr

Member
Mixed Farmer
Hi.
All hydraulics works fine. The problem that i has is that the oil flow at quick couplers is 24Lt\min at 2000 rpm. John deere manufactor gives 34lt/min minimum flow for the pump of my tractor.
So.... where are the rest 10lt\min....:LOL::LOL:
 

Cowabunga

Member
Location
Ceredigion,Wales
Hi.
All hydraulics works fine. The problem that i has is that the oil flow at quick couplers is 24Lt\min at 2000 rpm. John deere manufactor gives 34lt/min minimum flow for the pump of my tractor.
So.... where are the rest 10lt\min....:LOL::LOL:
Either you have an internal leak or your front pump is worn out and needs a rebuild. Could be something else entirely of course. I don’t think a good pump could sustain maximum output for long anyway, because the feed pump in the transmission can’t keep up. Cavitation and vibrating hydraulics are a clue to this.
 

SFI - What % were you taking out of production?

  • 0 %

    Votes: 80 42.1%
  • Up to 25%

    Votes: 67 35.3%
  • 25-50%

    Votes: 30 15.8%
  • 50-75%

    Votes: 3 1.6%
  • 75-100%

    Votes: 3 1.6%
  • 100% I’ve had enough of farming!

    Votes: 7 3.7%

Red Tractor drops launch of green farming scheme amid anger from farmers

  • 1,294
  • 1
As reported in Independent


quote: “Red Tractor has confirmed it is dropping plans to launch its green farming assurance standard in April“

read the TFF thread here: https://thefarmingforum.co.uk/index.php?threads/gfc-was-to-go-ahead-now-not-going-ahead.405234/
Top