Case 956XL

jd6820

Moderator
Arable Farmer
I've recently been working on a Case 956XL with a hydraulic fault, when warm steering judders and spools struggle to lift any weight. Pressure gauge plugged in from cold, indicates a continuous pressure drop even though no flow required, I find this strange as far as I am aware this tractor has no load sensing capabilities?

I'm thinking hydraulic pump, I removed relief valve and inspected for obstructions nothing found, I presume there is no way pressure can be dumped from both pumps to give the symptoms described as previous owner fitted new pumps and current owner thought they might be knackered so fitted a s/h pump off a breaker. I stripped down the original new pump and found wear and friction marks on gear surfaces so presume pump isn't as healthy as it could be?

Any suggestions? I'm thinking of testing pump itself by removing main pressure pipe and routing through my flow meter with an inline gauge and restrictor back to the tank to eliminate any circuits on the tractor.
 

McCman

Member
Location
Staffordshire
Check both washers are still on the aux tank dipstick, had one years ago that lost one and kept floating over the outlet hole on the tank and play havoc with the hydraulics. would do it every time after 5 mins running took weeks to find the problem after changing pipes and pumps several times !
 

Dave W

Member
Location
chesterfield
My 856 has some sort of draught control that seem to have a mind if it's own. i.e as the spray empties it gets lighter and the arms lift by themselves.
Probably not related but may be worth playing with draught control knob thingy.

Juddering steering would suggest low oil or some sort of priority valve problem but that's probably teaching you to suck eggs
 

jd6820

Moderator
Arable Farmer
Check both washers are still on the aux tank dipstick, had one years ago that lost one and kept floating over the outlet hole on the tank and play havoc with the hydraulics. would do it every time after 5 mins running took weeks to find the problem after changing pipes and pumps several times !
Washers on dipstick, that was first thing I checked. As for oil level checked this and checked for plenty of flow to pump. Draught control unlikely to affect steering and priority valve has been checked
 

Cooper3075

Member
Location
North Derbyshire
Mine dose strange things with the rear links since I bypassed the rear wing controls few years ago.
Filters ok nothing blocking any if the pipes in or out of them?
I had mine go weak after I think I got the oil hot running my hedge cutter on it on a closed centre spool block instead of a open on or vica versa steering went and hedge cutter went slow just about stoped unless in full revs. Parked it up and was fine next day swaped hedge cutter block round and been fine since.
 

jd6820

Moderator
Arable Farmer
Quite warm even though it's not been running for long I did notice this but wondered what could've been generating the heat. The oil doesn't smell burnt or look it.

No better when cooled down and restarted as soon as it gets warm it's poor again although it works fine when cold if a little weak on pressure side
 

Cooper3075

Member
Location
North Derbyshire
Mine was effectively trying to pump oil though the spool block all the time as I had the spool in flow but the hedge cutter only let oil though when I used the arm on it hence pump got oil hot but was on a few hours. Any chance a spool leaver is stuck? Do the arms go up still if spools stuck arms won't go up but will go down
 
Location
scotland
On a 956 one hyd pump is steering and the other is main hyds if it's a later model with the three hyd filters on rh side of engine it combines the steering pump into spool valve circuit for the first 30 secs but only one side of spool eg handle back ( I think ) look for magnetic switch on handle below console. Anyway I would do a flow and pressure test but as I,m sure you are aware of do not try and dead end the system if you are testing right at pump eg before relief valve, sounds like pump to me don,t you just love jobs when some other fecker has been there before!
 

jd6820

Moderator
Arable Farmer
Yeah, it makes diagnosis more difficult if someone has been before especially if you need to diagnose correctly first time due to a small budget, I hate for it not to be the pump after I'd suggested it was. Only a single filter on side of engine block, when testing it would have a return into tank filler through flow meter id then wind restrictor in till system pressure was reached so hopefully no pump damage should occur and I get a true flow reading.
 
Location
scotland
Single filter would indicate steering and hyds totally separate pressure circuits although drawing from same suction, I would also be checking suction pipes are clear along with your pressure test, gapples is the man on BFF to speak to regards mc3
 

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

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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/
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