New pump, same issues

[tommyg 152]

Well, I replaced my hydro pump in my d-180 with a good, solid working unit. However, the issues I was experiencing with high oil temps and power loss as the oil heats up haven't changed a bit. Exactly the same symptoms. In my estimation, the pump was not the problem at all. Anyone else have any ideas? Could the hydro moto be the issue? I'm not even sure where the thing is located!

[pfrederi 17,741]

Welcome to the world of tired Sundstrand hydros. Short answer yes the hydro motor could be the problem. It is mounted on the left side of the transaxle case. it is easier to remove than the pump portion.

I have picked up 2 pumps and at least 4 motors over the past year. Just about all were touted as coming from a working tractor. Well if it ran at all it must have limped into the boneyard as every one I have opened up has had internal issues.

Here is the diagnostic for over heating.

There is a thread here about working on renovating the pump/motor if you want to tackle the project.

The pump is the easier to overhaul (only special tool is a pair of 12 point sockets)...the motor requires an arbor press. You can check the acceleration valves with out the press.

Is your unit running ATF or 10w-30?

[JamesBe1 82]

It sounds like the only thing it could be is the motor. Fred is right in that it is much easier to replace than pump.

If you replace the motor, you will need a special sealing washer available from McMaster-Carr (PN 750-0002-1/2). They come in packs of five. I used one on mine, sent two to Steve in OK, and if you want, I can send one or two to you. They aren't expensive, but why buy five when you need only one.

I don't recall (maybe Paul can chime in here), but you might need the special square cut orings for the manifold. You will need a set of orings just like you did for the pump. Only this time it's much easier.

Keep your eyes open for a used motor on ebay.

Good luck, take pics and keep us posted with the progress.

James

[pfrederi 17,741]

James is correct you will need the same O ring / backer ring combination (there is one more small O ring than on you had to use on the pump

[tommyg 152]

I've heard of these so called "square cut" O rings. What exactly are they? I'm afraid I may have used the incorrect O rings when I installed my pump.

[pfrederi 17,741]

For teh high pressure ports there are two O rings. The first is a normal round profile O ring. The second is a backer ring. The have a rectangular profile (if you cut through one) and one side is slightly dished to match the profile of the first O ring. I broke down and bought a bag of teh large and small basic O rings from McMaster but I have never found a source for that size style of backer rings other than Toro. If someone could find a source that would be great.

[pfrederi 17,741]

If you want some basic O rings let me know you can have some also have the sealing washers (though I used a coper crush washer on mine 2 years ago without any problem.

[Hodge71 664]

Well, I replaced my hydro pump in my d-180 with a good, solid working unit.

Tommy,

I'm playing devils advocate here but how do you know for sure? Unless you physicallly took it apart to check slippers, pistons, swash plate etc. you're taking a shot in the dark.... Speaking from both Pauls and my experiences together over the last year, pretty much every pump on ebay and other sites all "came off a working tractor and have no issues". Once we opened them up we realized that some were worse than what we started with. I'm not saying people lie, but I will say they may not know exactly what a properly operating pump is, thats why they make the claims they do.

Now if you happened to check your pump and are 100% positive it was perfect then the next place to investigate is the hydro motor. When you look down from the top of the machine, under the seat, you will see 4 metal lines welded to a flange exactly like the pump end. You need to remove those 4 bolts and then locate the 4 mounting bolts that hold the pump to the transaxle housing. Its easiest done with the rear tires off. There is 1 bolt that goes from the right side of the tranny through to the left. Its 3/8-16 with a 9/16 head and is located above the hydro filter on the right side. Once you remove it and the other 3 bolts and nuts you can pull the motor free. Be careful when removing it and you can reuse the gasket. Inside the transmission you will find a very fine mesh screen, you will be able to take this out once the motor is off. Hopefully its free and clear of gunk. This is a prefilter and removes most of the larger gunk in the oil before it gets to the hydro filter and it also has a magnet on the end to grab any metal parts before they can do any damage. As Paul previously stated you will need an arbor press at minimum to pull your motor apart but once inside, its basically the same as the pump end which you have familiarity with if you took it apart to prove that it was indeed good and solid.

[JamesBe1 82]

Jeff gives a pretty good description of how to replace the pump. Good point about removing the wheel. I don't think there is enough room to work with without removing it. if you don't have the manual, you needs to get it and reread that section a couple of times. I followed it step by step and didn't have any trouble.

Before you go replacing the motor, did you replace the oil filter??? Not sure if starving the pump for oil will create the excess heat problem you point out, but in all my years of troubleshooting, it was always beat into me to check the simple things first. Can't tell you how many times I've seen people go crazy making difficult repairs only to find out that the issue was a minor component or adjustment.

Just thought I'd add that in the hopes that it may save you some trouble.

james

[JamesBe1 82]

For teh high pressure ports there are two O rings. The first is a normal round profile O ring. The second is a backer ring. The have a rectangular profile (if you cut through one) and one side is slightly dished to match the profile of the first O ring. I broke down and bought a bag of teh large and small basic O rings from McMaster but I have never found a source for that size style of backer rings other than Toro. If someone could find a source that would be great.

I second that. I'd love to find the OEM for those orings.

Jeff- did you mention that you installed your pump without the backer orings?

[Hodge71 664]

Jeff- did you mention that you installed your pump without the backer orings?

James I did indeed install mine without the square backing rings. But I must add that my orings were very thick compared to the factory rings. There was plenty of o-ring above the face of the flange. I also must say that that was on my old pump and motor assembly which after disassembly I saw that it was run totally out of oil and destroyed before I bought the tractor. After seeing the internals, I think I can pee with more pressure and flow than that abused pump was putting out. I am getting close to running the new pump and motor, hopefully by theend of this week or early next week, so we shall see if the new absolutely 100% factory pefect pump and motor that Paul and I rebuilt puts out enough pressure and flow to blow the O-rings out....

[can whlvr 993]

sure hope you can get it sorted,i dont have a d series,but a 160 with a sundstrand that died a few years back so i know what your going through

[tommyg 152]

Interesting about the O-ring combination. When I removed the old pump, there was only one set of O-rings, not two for the high pressure side. Perhaps the pump was removed and replaced at some point. And Jeff, I must admit... No, I did not tear apart the replacement pump. Decided to take a chance. Just looking at the splined shaft, it was way less worn than my original, so I decided to have a go. So... guilty as charged. However, after getting it installed and coming up with the same exact symptoms, it seems highly unlikely that the pump was in question from the beginning. You would think that it would either be better or worse. But it's not. It's the same. So, I may very well have had two good pumps and something else gone awry.

If I were to pressure test this pump, am I testing the entire system or just the pump itself? I'm thinking that if I can get a gauge on it, (assuming that I would be pressure testing only the pump) and verify that indeed the pressure is correct, even when hot, then I can likely assume that the issue is elsewhere... likely the motor. Is that a correct assumption? (Because we all know what happens when we assume. )

Oh, and James, yes, it's a new filter. And I agree with the "think simple first" mentality. It's some of the stuff that's most often missed!

[JamesBe1 82]

Interesting about the O-ring combination. When I removed the old pump, there was only one set of O-rings, not two for the high pressure side. Perhaps the pump was removed and replaced at some point. And Jeff, I must admit... No, I did not tear apart the replacement pump. Decided to take a chance. Just looking at the splined shaft, it was way less worn than my original, so I decided to have a go. So... guilty as charged. However, after getting it installed and coming up with the same exact symptoms, it seems highly unlikely that the pump was in question from the beginning. You would think that it would either be better or worse. But it's not. It's the same. So, I may very well have had two good pumps and something else gone awry.

If I were to pressure test this pump, am I testing the entire system or just the pump itself? I'm thinking that if I can get a gauge on it, (assuming that I would be pressure testing only the pump) and verify that indeed the pressure is correct, even when hot, then I can likely assume that the issue is elsewhere... likely the motor. Is that a correct assumption? (Because we all know what happens when we assume. )

Oh, and James, yes, it's a new filter. And I agree with the "think simple first" mentality. It's some of the stuff that's most often missed!

I think if you pressure test it, you will only be testing the pump.

Do you have a 3point hitch? If so, does it operate smoothly? Can you stand on the arms of it and raise yourself up? If you can't, then either the pump is not putting out enough pressure, or the pressure is not getting to the cylinder. If you can raise yourself up, it's not a guarantee that the pump is putting out the correct pressure, only that it is putting out enough pressure to lift you and that the pressure is getting to the cylinder.

Personally, I would skip the pressure test and go right to replacing the motor. But that's my opinion, not my advice. And we all know what opinions are like!

[tommyg 152]

Don't have a 3 point as much as I wish I did, but if I use the mower deck as a substitute, I've noticed that raising and lowering the deck is much slower after the transmission heats up.

[JamesBe1 82]

Don't have a 3 point as much as I wish I did, but if I use the mower deck as a substitute, I've noticed that raising and lowering the deck is much slower after the transmission heats up.

Hmmmmmm. I'd love to hear the other's opinion on this so far. Paul, Jeff, and Andy have a lot more experience than I.

If the raising and lower of the deck is the same as before, then either you have a 2nd bad pump or the system is having trouble flowing oil to the cylinder. I believe that the accessory ports come directly from the top of the pump with nothing to do with the transmission flow. A pressure test would be helpful, but I don't know if you have access to a 1000psi gage. I didn't have one handy when I needed one, and was too impatient to wait for one to be shipped to me. I went right for replacing the motor.

Let's hear what Paul, Jeff and Andy have to say.

Just a thought - if the pump is starved for oil, would that affect the implement pressure?

[Trouty56 567]

Since you have mentioned the deck....does the cylinder hold the deck or does it drift quickly down. Just trying to isolate this particular problem as not being a bad cylinder with blow by and to concentrate on either the pump or motor.

Wouldn't it be cool if a guy could get a hydraulic pump from harbor freight (just an example) and mount on these things. I know the rear end makes it impossible but it makes me wish for a solution with every post like this.

[tommyg 152]

No, the deck stays put. Just moves at about half the speed when it's cold.

[JamesBe1 82]

Since you have mentioned the deck....does the cylinder hold the deck or does it drift quickly down. Just trying to isolate this particular problem as not being a bad cylinder with blow by and to concentrate on either the pump or motor.

Wouldn't it be cool if a guy could get a hydraulic pump from harbor freight (just an example) and mount on these things. I know the rear end makes it impossible but it makes me wish for a solution with every post like this.

Can that seriously happen?

I have no problem admitting my ignorance in this case. Assuming it can happen, it would be a simple matter of capping off the implement outlets and seeing of that fixes the problem. Would be great if it were something so simple (yet obscure).

[pfrederi 17,741]

There are two pressure tests you can run on the pump. In both cases they test the charge pump. The charge pump is a gear-rotor pump that feeds the implement lift and feeds the piston block assembly. The piston block assembly takes the input from the charge pump and ups the pressure and transmits it to the hydro motor.

I finally got around to running the charge pump pressure test on my D this weekend. I got a reading of 100 lbs cold. (Unfortunately it was damn cold here last weekend). Left her outside running for 30 minutes and the hydro temp only got up to about 130 degrees still had 100 lbs but not a good test. (Manual suggests 70-150 lbs is acceptable). The follow on test is to raise a lift until the cylinder is fully extended at that point you should get 700lbs.

So yesterday it was warm out and I decided to run the implement test. (My 3 pt is sort of blocked by the FEL counter weights so I pulled up the midpoint lift handle and ...It Broke off. (Welcome to dysfunctional D land)

I have been through your issues. When I first got my D it could barely get out of its own way. Since the PO said the hydro motor had been "professionally rebuilt" (when I find that SOB !!!) so I replaced th pump. ( didn't know enough to open it and check it out)..no improvement. Took the old motor apart found that the "Professional" had used HVAC (green) O rings and large amounts of silicone. (later found he had just looked at the worn/scratched slippers and put the damn thing back together). I put on a different motor but didn't inspect it first. She runs OK now but will slowly heat up after an hour or so of use.

So now I am going to replace both the motor and the pump with units that I have gone over and renovated as best I can. I will do the motor first ...because it is a lot easier!!! and it appears at least the charge pump is acceptable. If she still over heats then the pump gets swapped out.

A couple of more thoughts...just because the pump passes the charge pump pressure test doesn't mean that its piston block valve plate and slippers aren't worn and allowing leakage (which causes weakness in power and heat build up.

That you mid mount get slow when hot is a bit if a concern, do you have a hydro pressure gauge? ( I could loan you one...) If it passes the charge pressure test then i would go ahead and replace the motor. When you get one I would strongly encourage you to open it up and check it over. You can open it up easily and check the pistons and slippers. (If they are worn get you money back and try again). Checking the valve plate would require using a press. (If the slippers are in good shape I might take a chance the valve plate is OK. Also check the acceleration valves they have a minute hole that can easily be plugged up or suffer from a broken spring. The motor to tranny gasket is still available from Toro the motor housing gasket is easy to make yourself.

Hang in there!!! It isn't as bad as it seems. Keep us posted

Edti: Are you using ATF or 10w-30???

[Trouty56 567]

Since you have mentioned the deck....does the cylinder hold the deck or does it drift quickly down. Just trying to isolate this particular problem as not being a bad cylinder with blow by and to concentrate on either the pump or motor.

Wouldn't it be cool if a guy could get a hydraulic pump from harbor freight (just an example) and mount on these things. I know the rear end makes it impossible but it makes me wish for a solution with every post like this.

Can that seriously happen?

I have no problem admitting my ignorance in this case. Assuming it can happen, it would be a simple matter of capping off the implement outlets and seeing of that fixes the problem. Would be great if it were something so simple (yet obscure).

Well no....I was just referring to the lift to be sure there was a relationship between the lift slowing and the motion slowing. I would think it possible to have good lift and poor motion. It is also possible to have a bleeding cylinder or valve and have good motion. Or a good pump and bleeding cylinder and bad motor....maybe I should just be quiet...lol....I'm digging a grave here.

[tommyg 152]

Paul, right now I have 20W50 in there to see if it made any difference. It didn't. I'm going to go back to 10W30 or 40 and just experiment. I have a crazy theory that the heavier weight might actually contribute to the heat build up in that it doesn't allow it to dissipate as quickly. Worth a shot anyway. I might take you up on your offer on the loaner gauge. Any special fittings required? Maybe you could PM me. I talked to the local Toro dealer. This guy grew up selling and repairing Wheelhorse tractors until Toro bought them out. Really know his stuff. I'm half tempted to just take the tractor over there and let him run some diagnostics on the hydro system and see if he can at least pinpoint the issue and give me his recommendations. Might be worth the 50 or 75 bucks.

[JamesBe1 82]

Tommy, you are right about the oil weight affecting the temperature, but the effect is minor. The manifold that runs the length of the tractor acts as a radiator to dissipate the heat. The more oil that flow though it the more it cools. Thinner oil will flow easier and cool quicker. But again, the effect is minor and will not be really notices unless running near the limits of performance.

Just thought I'd throw my two cents in the pot.

James

[tommyg 152]

Tommy, you are right about the oil weight affecting the temperature, but the effect is minor. The manifold that runs the length of the tractor acts as a radiator to dissipate the heat. The more oil that flow though it the more it cools. Thinner oil will flow easier and cool quicker. But again, the effect is minor and will not be really notices unless running near the limits of performance.

Just thought I'd throw my two cents in the pot.

James

Well I changed the oil back to 10w30, and while there was really no noticible difference in performance, the oil did indeed stay cooler. Maybe 15 degrees or so. The needle never got into the "caution" zone, but still too close for comfort. But at least I learned one thing.

[JamesBe1 82]

I think some of the larger D's actually had an electric cooling fan by the motor that blew across the metal lines. I saw one on ebay a couple of months back. I don't know if you want to consider something like that, since it doesn't really address the underlying cause. But a cheap 12v fan like they use in RV's and trucks might be easy to install. But it might also mask a larger problem that could get a lot more serious. Just a thought.