# Mahindra 1626 Loader Lift/Curl Leakdowns



## David David Morgan (Sep 18, 2020)

At 6 months of tractor age I reported a leak down and lift capacity problem to the dealer. They claimed it was normal and didn't do anything to fix it. I should have held my ground but it wasn't a 'big' problem at the time and I despise having to work with dealers. 

At 12 months of tractor age the problem had become significant enough with 800+ lbs of load I could almost see the loader arms leaking down and over less than an hour a set of forks would be on the ground from two or three feet in the air. The curl problem was more aggravated here as well.

I consulted the dealer. They troubleshot and said the problem was the loader control valve bypassing so they replaced it.

Problem didn't go away. In fact I believe it was then worse.

Took the tractor back to the dealer. They now believed the problem was the main loader arm cylinders bypassing so they had them rebuilt. The rebuilder told them there wasn't anything wrong with them but the dealer paid to have them rebuilt anyway.

Problem still exists. No improvement. (Note: I'm not sure how they came to the arm cylinders being the problem when the curl cylinders were behaving the same way.)

So before I take the d**n thing back again I thought I'd query the forum for ideas on what this problem is caused by. If the bypass is not the control valve OR the cylinders where is it bypassing (if that's the problem)?

I'm going to test the backhoe today and see if I see the same leakdown with its boom.

Could this be a bad pump not holding pressure? Is there a check valve in this type of system that might be weak?

I'm ordering parts for a pressure test valve for troubleshooting although I don't think is a distinct pressure problem. I think its a problem of pressure being maintained.

Any ideas guys??

(Might be posting a YouTube video)


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## BigT (Sep 15, 2014)

Good Morning David,

I feel that it is unrealistic to expect any loader or lift system to hold a load up for an hour without bleeding down to some degree. It is not good practice to leave your lift or loader sit in the air with a load on it for an extended time period. You risk gradual erosion of the seals over time. Below is a U-tube presentation on the subject:


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## Fedup (Feb 25, 2014)

I don't know what they use on newer tractors, but some years back the loaders on many Mahindra tractors came with Nimco valves. Not the greatest product out there. Your symptoms could well be just that. A cheap valve. It was replaced with another (probably just like it) and the problem is still there. I can't prove that of course, but it's a good possibility. 

Piston seals in some of the loader cylinders could be less than perfect, but I'd bet on the valve since it affects both circuits, and you think the new valve may be worse than the first. There are ways to test both, but without a lot of fittings, extra hoses and parts, that's not something I would suggest, nor something YOU should have to do or pay for. 

What would I do? I would get with the dealer and try to work a deal whereby they replace the valve with a better quality unit, whatever that takes. I know warranty then comes into play, they will claim it would void the warranty, and all that, but who really cares? The warranty on the valve is currently worthless to you anyway.


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## David David Morgan (Sep 18, 2020)

BigT said:


> I feel that it is unrealistic to expect any loader or lift system to hold a load up for an hour without bleeding down to some degree. It is not good practice to leave your lift or loader sit in the air with a load on it for an extended time period.


I'm no hydraulic mechanic but I've sat quite a few units of road construction equipment and I never met an operator who would put up with leak down. Why do used equipment dealers leave booms in the air? To show they don't leak down. And I can tell you that when I was a lineman a bucket truck that leaked down any at all, did NOT leave the shop till it was repaired.

And, I'm not leaving this tractor parked with booms raised for no reason. This thing is leaking down while I'm using it. That's unacceptable. Do you think it's acceptable to park a backhoe and come back a half an hour later and the boom and bucket is on the ground?


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## David David Morgan (Sep 18, 2020)

Mahindra must be ahead of New Holland because they're working on this problem under warranty.


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## David David Morgan (Sep 18, 2020)

Update: outriggers leak down as well. So it's every cylinder system leaking down. System wide problem. They replaced the loader control valve which wouldn't affect the hoe control valve function. So it's got to be some kind of system check valve like problem. Haven't found a parts diagram for this yet.

Als, don't discount that the tractor won't lift anywhere near its rated lift capacity. Are we supposed to accept that as well Mike?

Right now the tractor won't lift or curl a half full 275 gallon water tote. Here's a video of a dealer demo of it doing exactly that: 




Here's a video of an owner lifting ~2000. 




The tractor is rated to lift 1560 lbs.


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## sixbales (May 18, 2011)

Brings to mind the old addage: "You get what you pay for".


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## David David Morgan (Sep 18, 2020)

This is the only problem I've had with this tractor and this problem hasn't shut me down at all. We just cut 22 60 to 70 foot cedar trees along the fence-line. My 1626 dragged them all back into the woods and piled them up. It dug all the stumps and carried them to the tree pile. It's dug several hundred feet of trench for sewer lines and moves around 20' sticks of 24" cast iron water pipe like a champ. I've used it for so many things it's pitiful. I got much more than I paid for so far. I'd buy a Mahindra again in a heart beat based on my experience with this one.


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## Busted Tractor (May 22, 2018)

The hydraulic pump only moves oil. A restriction or load creates pressure. It is NOT the pump that is causing your problem. If the pump is bad it will not create full pressure.

The control valve is internally sealed by oil sealing the lands of the spool and housing. Spools are supposed to be select fit to the housing and are not replaceable or interchangeable. The only O rings or seals in a valve are at each end of the spools are keep oil from leaking out or dirt from entering. Some valves have what is called a load check. It keeps the loader from dropping when you raise it, Then pressure has to overcome the pressure in the lift circuit to unseat the valve and raise the loader

Double acting cylinders are sealed on the rod end by O rings or another type packing they also have some type of wiper to keep dirt from entering. The piston that moves within the barrel can be sealed with O rings, cups, or other type of packing. Most leak downs are caused by the seals on the piston, because they move and wear they can also be damaged by dirt, grit or foreign objects in the oil.

How to find the leak. With the loader raised with a load on it. Take a pipe or stethoscope (like a doctor uses) put it against the suspect and with the other end to your ear listen for a swishing or whooshing sound. If you hear the swishing or swooshing noise you have found the leak. You can do this on the cylinder or the valve. The more the load the easier to find the leak. Be sure to check both cylinders, one may leak and one may not.

When I worked for a dealer we had customers come in and ask for a new pump, or some would ask for a new valve. After we asked them why they needed these parts they would say "the loader leaks down" or "the bucket won't stay back". After some discussion and teaching them how to listen for a bypassing cylinder 98% came back with leaking cylinders. Any valves that were replaced was due to them cracked and leaking oil externally.

Hope this helps


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## David David Morgan (Sep 18, 2020)

Good stuff Busted. Thanks.

As I noted in my initial post the loader control valve was replaced and it made zero improvement. 

There are two lift cylinders and two curl cylinders. I've got leak down in both functions; won't curl and won't lift as much as it should.

The last time in the shop they sent the two lift cylinders out for rebuild. The rebuilder called and said they didn't need rebuilding. The dealer claims they had them rebuilt anyway. Anyway, rebuilding the two lift cylinders had no effect for better or worse.

I've got a system wide leak-down issue:

the lift cylinders leak down
the curl cylinders leak down
the backhoe boom leaks down
the outriggers leak down

No single cylinder rebuild is going to fix that. No single control valve replacement is going to fix that.

The answer to the problem is to determine what main system component is bypassing that will affect the entire hydraulic system.

The only part that I would think could cause that is some kind of check valve and if there is one I can't find it in the parts catalog. The dealer obviously doesn't have a clue either.


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## Fedup (Feb 25, 2014)

There is no single check valve. Think about it. Where could such a thing be placed where it would affect ALL portions of your system. With an open center system oil flows from the pump through all series plumbed valves whenever the pump is turning. 

Trapped oil is just that. It's trapped in each individual cylinder, its two lines, and the valve that controls or supplies it. The check valve(s) are the load checks within the valve, and the spool to body clearances. If you have leak down on each cylinder, then you have leak down in each of those circuits. No single component can cause that. As for your new loader valve having no effect. If you replace an ineffective part with another just like it, you're likely to get the same result. 

If your cylinders are leaking down, that trapped oil has to be going somewhere. If it's not going on the ground, it's going from one side of the piston to the other (even that's questionable, given the volume difference between the two sides), or it's going back into the system through the valve.


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## David David Morgan (Sep 18, 2020)

I'm out.


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## joninva (Aug 15, 2021)

If you think it's not able to lift its rated capacity, get a gauge and check the hydraulic pressure. Warm the tractor up before checking it.


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## westbay6 (Oct 10, 2020)

Hi David,

The one thing I haven't seen discussed here yet is the one other part that does touch all of those cylinders: the hydraulic fluid itself. I would check to see if the hydraulic fluid is becoming aerated. 

This exact same thing happened to me when I had a FEL with an external front mounted hydraulic pump. The suction line from the hydraulic tank going to the pump had a very small leak that would allow air to be sucked into the pump along with the fluid. After just a short while of running, all the cylinders would leak down and the lift capacity was greatly reduced. I looked at the hydraulic fluid and it was foamy, full of bubbles. Fixing the leak solved my problem immediately.

I'm not sure how the hydraulics on your tractor are arranged, so there might not be any way for air to get into the suction side, but in case there is, it's worth checking the fluid for aeration. Maybe run your tractor for 10 minutes and look at how foamy the fluid is, then see if the dealer will let you compare that to one of their new tractors.


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## 47ford (Oct 1, 2019)

David David Morgan said:


> At 6 months of tractor age I reported a leak down and lift capacity problem to the dealer. They claimed it was normal and didn't do anything to fix it. I should have held my ground but it wasn't a 'big' problem at the time and I despise having to work with dealers.
> 
> At 12 months of tractor age the problem had become significant enough with 800+ lbs of load I could almost see the loader arms leaking down and over less than an hour a set of forks would be on the ground from two or three feet in the air. The curl problem was more aggravated here as well.
> 
> ...


The dealer should’ve checked into deeper, it probably has load check leaking it can be fixed.
I would question the dealer about it, fixed a few when I worked for Case equipment.


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## tharpricky (4 mo ago)

David David Morgan said:


> I'm no hydraulic mechanic but I've sat quite a few units of road construction equipment and I never met an operator who would put up with leak down. Why do used equipment dealers leave booms in the air? To show they don't leak down. And I can tell you that when I was a lineman a bucket truck that leaked down any at all, did NOT leave the shop till it was repaired. And, I'm not leaving this tractor parked with booms raised for no reason. This thing is leaking down while I'm using it. That's unacceptable. Do you think it's acceptable to park a backhoe and come back a half an hour later and the boom and bucket is on the ground?


 Backhoes and bucket trucks have check valves and these loaded/backhoes don’t and rely on spools to hold the load. Then there is spool leakage around the spools. Cheap valves vs expensive good quality valves


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## 2billt (Aug 7, 2011)

Two reasons previously mentioned, spool valves or fluid degradation. I would lean more toward spools than fluid simply because you initially had problems at 6 months with the front and subsequently later with the rear. I would contend that if it was marginally fluid related it would show up at least with all the heavy controls simultaneously. Therefore, it leaves me looking straight at the control valves with weak spools. Given that the loader had problems with both functions simultaneously would have been my #1 focus, if dumped off at my doorstep. 
I find it hard to believe they would send two cylinders out, coincidentally, for the same problem, Wow, I would have been fired for the suggestion.


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