John Deere 3140 Hydraulic problems

Caffrey78

I have a ~1981 John Deere 3140 with hydraulic problems. I have replaced the filter, cleaned the screen and replaced the oil. The spool valves are generating about 180-200bar (2800-2900psi) at idle, my gauge was only rated to 150bar so I've a larger one on order. The pressure is constant and instant. The oil level is quite low, below min mark on the dip stick, so I can only assume the pumps are working well. The problem is the 3 pt linkage shudders when lifting just the arms never mind a heavy bale, at idle speed the steering doesn't work properly and needs higher revs, the lift will stop lifting at low revs if I turn the steering. During a couple of hours work lifting anything heavy the oil almost boils. The 3 pt linkage will drop a heavy load unless the revs are flat out and especially when you use the hi lo changeover in the gears. When I listen in the filler cap I can hear liquid spitting inside. When the tractor is turned off the 3 pt linkage drops in about 5 seconds with a load on behind. Is there any way of isolating the problems to a single cylinder which is causing the problem.

corkcomp

your hydraulic pump is in trouble, your pressure is grand, maybe even a little high but it's no use as it sounds like your Gal/Min (flow rate) is too low.

edit: maybe im mis-reading your post but why don't you bring the oil up to max mark on dip stick if it's low??

John J. Lyons

Sounds like your pump is in trouble, had a problem like this last year the lift shudderd to go up but lifted perfect to steer the tractor it had to be reved up and the lift would drop when turned off - there was a slight knock in the main hydraulic pump up front when under pressure , I have also seen feed pipes crack and brake due to vibration in the back -end, but I would get the pump looked at first as it's a common fault on these

howdoyouknow

Caffrey78 wrote: »

I have a ~1981 John Deere 3140 with hydraulic problems. I have replaced the filter, cleaned the screen and replaced the oil. The spool valves are generating about 180-200bar (2800-2900psi) at idle, my gauge was only rated to 150bar so I've a larger one on order. The pressure is constant and instant. The oil level is quite low, below min mark on the dip stick, so I can only assume the pumps are working well. The problem is the 3 pt linkage shudders when lifting just the arms never mind a heavy bale, at idle speed the steering doesn't work properly and needs higher revs, the lift will stop lifting at low revs if I turn the steering. During a couple of hours work lifting anything heavy the oil almost boils. The 3 pt linkage will drop a heavy load unless the revs are flat out and especially when you use the hi lo changeover in the gears. When I listen in the filler cap I can hear liquid spitting inside. When the tractor is turned off the 3 pt linkage drops in about 5 seconds with a load on behind. Is there any way of isolating the problems to a single cylinder which is causing the problem.

I had simaler problems with a 3130 and it was the oil feed lines running from the front pump to the rear that were at fault. I noticed that the problems got worse when the tractor was warm and the oil thinner. If it is the oil lines you need to split the tractor as the lines run inside the backend. They leak into the oil resivoir so you don't know you have a leak.

Caffrey78

Thanks everyone for your replies.
I've ran the engine flat out for two years drawing bales in and because of this there is now a small leak from the front pump which explains the low oil in her at the minute. The tractor brings in the bales, rolls the land and carries buckrakes of bedding from the sheds and thats about it so she's due a top up of oil for the next onslaught of bales.
There's no other reason for the low oil.
There are no other external leaks I can see so it is an internal problem.
I rechecked the pressure and she building 3200-3300psi idling and this fluctuates by ~100psi with a decent rev.
Are you all talking about the Hyd pump in the nose or the Charge pump in the main body?
Would the cracked feed lines cause the arms to drop that quickly or is this more associated with valve not closing properly.
Great tractor if it would only lift!!

corkcomp

running with low oil is madness anyways, you should top it up when it goes down irrespective of season as you will only damage the front pump. I would top up for starters and see if it's any better.

If that doesnt improve things you could disconnect the feed line to front pump, have a bucket ready and start the tractor for 5 - 10 seconds, I had a similar problem and was able to rule out the charge / internal pump by doing this. The lift arms dropping could be a separate problem, seals in rams maybe as mine would hold up a plough at idle revs even with a bad pump.

Caffrey78

Topping up the oil has no effect on the performance of the lift.

Can a pressure gauge be put on these hyd pump feed pipes to check the internal pump.
Should it fill the bucket in those 5 secs or how can you be sure the internal pump is fine.

howdoyouknow

http://www.youtube.com/watch?v=n4njMoKF7Ac&feature=youtube_gdata_player

Over engineering at its finest

John J. Lyons

Get a flow meter to check your main hydraulic pump up front , top up the back-end oil also as its not good for the packs, its quiet possible that an oil feed pipe may have cracked /broken in the back end, will it lift a bale when reved up and stay up when the tractor idels?

Caffrey78

Eventually, when the oil gets too hot, she really struggles to lift and will not hold at idle revs. There's nothing else for it but head for tea and let her cool down. Even when the oil is cold the 3pt will lower itself and re-raise with a simple bale lifter on.
I've looked at that vid clip many times.
I've just dropped her off this morning to a garage to get her checked and hopefully then repaired.
I don't have enough time with work to start into this unfortunately and with bales looming I don't want to be stuck with nothing.
I'm looking forward to putting a double bale lifter on her this year.
I'll keep everyone updated with what the mechanic finds.

Caffrey78

So far the diagnosis is an injector down on the hydraulic pump. Thankfully the internal pump looks fine. Lets hope the good run of no major faults continues.

Caffrey78

Hydraulic pump has been repaired and now she's putting up constant pressure which has sorted the steering. A dump valve inside the back wheel is worn and may be dumping the pressure. Not sure what the valve is called or what exactly it does but I'll figure that one out later. It's been swapped out in the morning.

Caffrey78

Just chatting to my mechanic last night. The hydraulic pump has just been sent to a fella in Dublin for a complete check, it seems to be steady but not building enough pressure even with adjusting the screw underneath.
He's pretty sure there's no leak inside because the charge/internal pump is filling the front reservoir and wouldn't be doing so if there was a leak.
He reckons that because my hi lo shift and 4wd are working that that all leads to everything inside being ok.
If this is true then that's good news for me and labour costs.

Any opinions.

iverjohnston

You seem to have several seperate problems. Good to get your main hyd. pump overhauled, and as you say, your charge pump in the transmission is keeping the resovoire filled. The 3 point linkage falling has to be caused by either leaking spool valves or the O ring on the main lift piston is damaged. This O ring is just a spft rubber ring with a nylon tyoe backing ring for strenght. As the rockshaft wears it allows the piston to emerge from its cylinder, enough for the O ring to get nipped when the piston returns into the cylinder (ie, when the arms are let down again.) You will have to lift the cab and take off the top of the rockshaft to fix this. If there is a piece missing from the O ring, handiest fix is to get a local engineering place to machine a new groove in the piston, half an inch or so back from the existing groove. Mack in Cavan

iverjohnston

Also, the steering gets priority in the oil supply, so you must fill up to the mark on the dipstick as a first step.

Caffrey78

The lid has been removed and all seals have been replaced. I hope to have her back tonight or tomorrow for a test drive to see what's working. I hope that's everything. I had a feeling that there had to be seals gone under the lid and a serious enough leak because of the temperature the oil was getting to in a short space of time. Thanks for your comments and I'll keep this thread updated as i go on. All I need now is weather to make bales!!

iverjohnston

there is a plug screws into the end of the main lift cylinder, removing it allows you push out the piston with a piece of dowell rod or whatever. Don't forget to replace this or you wont be lifting anything! Ask me how I know this:rolleyes:! Also the "rate of drop" screw needs to be checked.

Caffrey78

The latest is a cracked lift cylinder, is there any end to the good news.
That's supposed to be replaced today with a 2nd hand one.
I think I'm getting her back tomorrow for a test drive.

iverjohnston

That wouldn't be too bad, easily swopped out (as our american cousins say!) A mate of mine bought a 3650 and it would do something similar. When it got hot you lost hydraulics. They changed filters, the main pump (twice) and still the problem persisted. M. F. M were down about 4 times.They split it and checked the hi-lo and the clutch packs and replaced the oil lines in the gearbox. No joy. Then the engins seized so that was that. We had reached the conclusion tht there had to be a crack or a blow hole somewhere in the back end. She went away on a truck and he bought a new 6510. The garage told them about a year later than the engine was rebuilt and she was going good. There was a story there somewhere, but the garage wasn't telling!

Caffrey78

The mower is booked for Friday and baling Saturday, so that's definitely D-day for her.
If I can face a laptop Saturday night I'll let you know how she is, but after a full day bouncing up and down the road I might be more in the mood for pints, especially if I need to borrow a neighbours tractor.
My mechanic was very good, he didn't jump in and start splitting her down to find the problem was external. I suppose with the weather the way it is he was under no major pressure to get her fixed. You mates story is one that would wreck your head,
I have no idea of the cost of this so far, that could be the biggest shock of all.

Caffrey78

101 bales drawn in Saturday with a neighbours MF375, yer man broke a control valve and gear rod trying to fix a leak on Saturday morning so after all the expense she didn't even get out the door.
Not to worry there's another 100+ in a couple of weeks when this heatwave hits, that's her next target.

iverjohnston

Do'nt you just love machinery.................... What part of the country are you in, by the way? Mack in Cavan

Caffrey78

Fermanagh and she's in a garage in Stradone outside Cavan.
Yer man's doing a good enough job as far as I can see so I'm not in any panic to change just yet.
I should have said that I had help with the 101 bales in the form of my brother (and partner in crime) on an International 585.

iverjohnston

Well your mechanic isn,t too far from Conatys in Sylvan Park, kells, who will have everything you nees second hand.

Caffrey78

The tractor debacle continues. I went Saturday to collect her, after being told that she was finished. I tried to take her for a spin but couldn't get 2nd & 3rd. Eventually when this was kind of sorted I headed up the road only to find the hi lo split in each gear was plumbed backwards!! I left her there and will be ringing later this evening to see what the latest is.

Man of Aran

Caffrey78 wrote: »

The tractor debacle continues. I went Saturday to collect her, after being told that she was finished. I tried to take her for a spin but couldn't get 2nd & 3rd. Eventually when this was kind of sorted I headed up the road only to find the hi lo split in each gear was plumbed backwards!! I left her there and will be ringing later this evening to see what the latest is.

What kind of workshop did you take it to ? .... sounds like Mr Haney's place on Green Acres show !

Hope it gets sorted anyhow.

Caffrey78

Man of Aran - It's a decent workshop to be fair and yer man is well clued in. He runs a plant and tractor repair business. I'm putting it down to just bad luck.

No answer lastnight so no update.

Man of Aran

How's she cuttin' now Caffrey, hope it 's sorted for ya?

Caffrey78

I've mixed news.
Pos: Just drew home ~90 bales on saturday between two tractors.
Everything working well, lifting bales sky high and tilting with the hyd toplink all at idle revs. This was so different to before, no worry about the lift dropping at any stage. Split gears working fine and not affecting the lift performance.

Neg: I got through about 25 bales and eventually she needed a decent rev to lift the bale and also to have steering. Once up, she would hold firm with the engine idling. To take off again I needed to rev hard to build up pressure to get the steering going. That rev was needed for the last 20 bales or so. I parked her up with the lifter up and it has stayed up since.

Nothing like before so big improvements all round but unfortunately not 100%.
The work done on the lift cylinder and seals has eliminated all the lifting/dropping issues but because the steering is failing I'm not sure the hyd pump reconditioning has been totally successful - any thoughts??

iverjohnston

The steering gets priority , first in line for the oil from the pump.There is a valve to ensure this happens. I will look up a workshop manual I have somewhere. I assume the main hydraulic oil filter was changed? and the strainer? Nigel in Cavan

Caffrey78

Yes main filter and suction screen changed with a fill of new oil. It took until the oil was at it's hotest for the problem to show, it was a sickening blow.