644 hydraulics

6300 Views 25 Replies 5 Participants Last post by Hydriv, May 9, 2011

jlemerson

Discussion Starter · Apr 23, 2011

I have a 72 644 that I have upgraded with a 18 hp vanguard. Problem I’m having is the 644 runs fine for the first 15 or 20 minutes then looses power thru the hydraulics. The oil does get hot. I’m running 30 weight and yep the fan is turning in the right direction. Would this be a indication that the pump is not functioning correctly or other? (Yep Tom this is the basket Case I put together in my basement LOL.) I just installed a tiller control valve and had a chance to run the tiller off the 644. I must say I like it on the 644 with the foot control a lot better then on my 446.
John in Bloomington In

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Hydriv

· #2 · Apr 23, 2011

The fact that you put the Vanguard in this tractor has no bearing on the issue. I am trying to understand your complaint so let's talk about that.

Are you saying that the engine seems to lose power in some fashion? If so, then please describe what happens?

You say that the oil gets hot. How hot is hot? Does your wife have an oven thermometer that you can stick in the oil reservoir to read the true temp?

When you installed the rear PTO valve, did you take note of the words IN and OUT on the casting right where the lines enter and exit? Are you positive that you have it plumbed correctly? The parts book seems to indicate that the pump output goes directly to the IN port on the rear PTO valve and the OUT port on the PTO valve goes to the IN port on the travel/lift valve just as it does on the 200 and 400 series GT's.

This tiller control valve you installed. Is this a factory valve or something that you got elsewhere?

jlemerson

Discussion Starter · #3 · Apr 23, 2011

Hydriv said:
The fact that you put the Vanguard in this tractor has no bearing on the issue. I am trying to understand your complaint so let's talk about that.

Are you saying that the engine seems to lose power in some fashion? If so, then please describe what happens?

You say that the oil gets hot. How hot is hot? Does your wife have an oven thermometer that you can stick in the oil reservoir to read the true temp?

When you installed the rear PTO valve, did you take note of the words IN and OUT on the casting right where the lines enter and exit? Are you positive that you have it plumbed correctly? The parts book seems to indicate that the pump output goes directly to the IN port on the rear PTO valve and the OUT port on the PTO valve goes to the IN port on the travel/lift valve just as it does on the 200 and 400 series GT's.

This tiller control valve you installed. Is this a factory valve or something that you got elsewhere?

The engine doesn't loose power the hydraulics does. The pto valve is installed correctly with the in and out as marked. The control valve was a factory valve. I will check the heat readings tomorrow. Thanks for your reply, sorry I didn't supply enough information.........

Hydriv

· #4 · Apr 23, 2011

More questions, John.

I know that you struggled with the pump on this tractor and if I recall correctly, the pump rotation was wrong. Yes?

When you finally got that problem corrected, was the rear PTO valve on the tractor or did that come later?

If it came later, did you get a chance to put the tractor and loader through its paces by working it hard? Did you notice any issues with the tractor prior to adding the rear PTO?

You say that you lose hydraulic power. In what way? Does the tiller stop working? Tell me what you were doing at the time you noticed this loss of power.

jlemerson

Discussion Starter · #5 · Apr 23, 2011

Hydriv said:
More questions, John.

I know that you struggled with the pump on this tractor and if I recall correctly, the pump rotation was wrong. Yes?

When you finally got that problem corrected, was the rear PTO valve on the tractor or did that come later?

If it came later, did you get a chance to put the tractor and loader through its paces by working it hard? Did you notice any issues with the tractor prior to adding the rear PTO?

You say that you lose hydraulic power. In what way? Does the tiller stop working? Tell me what you were doing at the time you noticed this loss of power.

I did struggle with the pump on this tractor but with your help I got it figured out and it did spin correctly when finished. The 644 then had a 14 hp k on it and I thought the k was bad because of the lack of hydraulic power so I changed the engine to the vanguard. There is no lack of power with the vanguard. The power for the hydraullics seems to be there for 15 or 20 minutes or until the tractor gets warmed up then not only does the tiller slow down but the tractor drive power is not there. This happen before the tiller and the valve was added. My question is would a pump cause this or some thing else? Would the pump cause this problem or should I start looking for other areas?

Hydriv

· #6 · Apr 23, 2011

Let's see what the temp of the oil is, once you have been working the tractor hard.

horton20

· #7 · Apr 23, 2011

You need a pump, I went thur the same thing with both my 644. I put a 200 series pump on both of them. You may have to change the in let fitting, just has an o ring, so twist an pull the rest will work good. If you need me for help call 9379354833 horton 20

Hydriv

· #8 · Apr 24, 2011

John,
Steve may well be correct. I'd still like to know the oil temp because a bad pump does not cause high oil temps but super hot oil can cause the issues you are complaining about.

It would appear the Steve installed a used pump and pump mount from a 200 series to solve his problem. Your tractor uses a different style of pump that can be had for around $200.00. I don't recall if you ever purchased a glycerin filled pressure gauge or not but this would be a good time to own one. Since you have a PTO on the rear, all you need is the gauge and a few fitting to adapt that gauge to the quick coupler you need to remove from the tiller hose. That will allow you to attach the gauge to the mating quick coupler on the PTO valve and check the pressure. Let me know when you are ready to do that and I will cover that procedure in more detail for you if you feel you need the assistance.

jlemerson

Discussion Starter · #9 · Apr 24, 2011

Hydriv said:
John,
Steve may well be correct. I'd still like to know the oil temp because a bad pump does not cause high oil temps but super hot oil can cause the issues you are complaining about.

It would appear the Steve installed a used pump and pump mount from a 200 series to solve his problem. Your tractor uses a different style of pump that can be had for around $200.00. I don't recall if you ever purchased a glycerin filled pressure gauge or not but this would be a good time to own one. Since you have a PTO on the rear, all you need is the gauge and a few fitting to adapt that gauge to the quick coupler you need to remove from the tiller hose. That will allow you to attach the gauge to the mating quick coupler on the PTO valve and check the pressure. Let me know when you are ready to do that and I will cover that procedure in more detail for you if you feel you need the assistance.

Steve gave me some very good input and I appreciate that. The weather here has been nothing but rain for the past few days making it hard to take the 644 out and work it but gives me some added time to play around and check things out a little more before changing pumps. I did start it up and let it run for 30 minutes with the tiller in motion but that is not working for accurate measurements. The temp read around 70 degrees at the end of 30 minutes and I know it gets a lot hotter then that when I work it. I hooked a glycerin filled pressure gauge to the tiller valve and it stalled out at 2200. I might of not had it hooked up right? I do have an extra 200 series pump that will work on my 644. Its the same size as the one that is on there but the outlet is a tube not a fitting.
Hydriv thanks for your help.
John in Bloomington In.

Hydriv

· #10 · Apr 24, 2011

John,
If your pump will make 2200 PSI, then it is not worn out.

70 degree F oil does not seem possible. You must mean 70 degrees Celsius and that would equate to 158 F which is a temp I could believe. But it is also a very reasonable temp for oil.

Your tractor has an oil cooler and a fan to move air through that cooler. The 646 does not have that fan.

Overheated oil can come from a cooler with plugged fins or with loose fins that fail to radiate heat. It can also come from the oil being forced through a restriction in the system. Such a restriction would show up if you hooked that gauge to the drain plug hole in the travel/lift valve, started the tractor and ran it at full throttle. You don't touch or move anything to conduct this test. We are just looking at how much pressure the pump needs to make to push the full flow of oil through the system.

The last thing would be if you had an oversize pump that was pushing way too much oil and the size of the lines in the tractor were restricting that flow. What do you know about this pump?

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jlemerson

Discussion Starter · #11 · Apr 25, 2011

Hydriv said:
John,
If your pump will make 2200 PSI, then it is not worn out.

70 degree F oil does not seem possible. You must mean 70 degrees Celsius and that would equate to 158 F which is a temp I could believe. But it is also a very reasonable temp for oil.

Your tractor has an oil cooler and a fan to move air through that cooler. The 646 does not have that fan.

Overheated oil can come from a cooler with plugged fins or with loose fins that fail to radiate heat. It can also come from the oil being forced through a restriction in the system. Such a restriction would show up if you hooked that gauge to the drain plug hole in the travel/lift valve, started the tractor and ran it at full throttle. You don't touch or move anything to conduct this test. We are just looking at how much pressure the pump needs to make to push the full flow of oil through the system.

The last thing would be if you had an oversize pump that was pushing way too much oil and the size of the lines in the tractor were restricting that flow. What do you know about this pump?

I hooked the gauge to the drain plug hole in the travel/lift valve and started the tractor not once but several times. The indicator never left the mark. The pump came with the tractor. I know very little about it other then it is shown in the manual to be correct. The fins on the cooler seem to be solid with no pluggage.
I have a question??? What about the travel control valve relief? Could it be faulty? I know very little about such things.
John in Bloomington In.

Hydriv

· #12 · Apr 25, 2011

John,
In order to get a reading off of the drain/test port on the underside of the travel/lift valve, you have to provide a load on the tractor. The easiest way to do this is to put the trans-axle in Hi Range and then put the bucket an inch above the ground while pushing up against something the tractor cannot move. That could be a pile of stone or dirt or a dead tree, block wall etc. The engine must be at full throttle and you need to push the pedal to the metal which watching the gauge. The pump will not make pressure unless you force it to and this test does just that.

Let's see what the readings are before leaping to any conclusions about the relief.

jlemerson

Discussion Starter · #13 · Apr 25, 2011

Hydriv said:
John,
In order to get a reading off of the drain/test port on the underside of the travel/lift valve, you have to provide a load on the tractor. The easiest way to do this is to put the trans-axle in Hi Range and then put the bucket an inch above the ground while pushing up against something the tractor cannot move. That could be a pile of stone or dirt or a dead tree, block wall etc. The engine must be at full throttle and you need to push the pedal to the metal which watching the gauge. The pump will not make pressure unless you force it to and this test does just that.

Let's see what the readings are before leaping to any conclusions about the relief.

Up against a tree with the bucket around 1 inch from the ground and at full throttle it read 1200 The tires were spinning do to the rain.
John in Bloomington Indiana

Hydriv

· #14 · Apr 25, 2011

John,
You need to pick a dry day to eliminate tire spin. You are not loading the pump enough. Are you in HIGH RANGE?

jlemerson

Discussion Starter · #15 · Apr 25, 2011

Hydriv said:
John,
You need to pick a dry day to eliminate tire spin. You are not loading the pump enough. Are you in HIGH RANGE?

Not in high range. A dry day LOL calling for rain here for the next 6 to 7 days been raining for the past week or more.
John in Indiana

Hydriv

· #16 · Apr 26, 2011

John,

You need to pay attention. :sidelaugh:

I told you to use Hi Range. I will have to think about what the penalty will be. :lol: :lol: :lol:

Try the test again tomorrow and see if you get in wheel spin in Hi Range.

Protrucker

· #17 · Apr 26, 2011

Hydriv said:
John,

You need to pay attention. :sidelaugh:

I told you to use Hi Range. I will have to think about what the penalty will be. :lol: :lol: :lol:

Try the test again tomorrow and see if you get in wheel spin in Hi Range.

:lol: You just want him to sling mud all over & get covered with it! :sidelaugh: :sidelaugh: :sidelaugh:

jlemerson

Discussion Starter · #18 · Apr 26, 2011

Protrucker said:
Hydriv said:

John,

You need to pay attention. :sidelaugh:

I told you to use Hi Range. I will have to think about what the penalty will be. :lol: :lol: :lol:

Try the test again tomorrow and see if you get in wheel spin in Hi Range.

Click to expand...

:lol: You just want him to sling mud all over & get covered with it! :sidelaugh: :sidelaugh: :sidelaugh:

Ok at 7 this morning I picked a new tree, the rutes near the other from yesterday were to deep

Results reading was 2000 the engine slowed down but did not die out. I mentioned that when I was tilling I lost power to the tiller and the drive after about 20 minutes of operation. The tiller valve is pumbed dirrectly from the pump then goes to the travel control valve. But before I added the tiller valve I had the same problem. I'm going to try to work with it today and see if I can get the oil to heat up and get another reading. This is getting very :crazy:
John in Bloomington Indiana

Hydriv

· #19 · Apr 26, 2011

Frustration should be something you are accustomed to by now, considering what you have been through so far with this tractor's hydraulic system. :facepalm:

The readings you are getting, certainly indicate that the pump is capable of delivering adequate pressure to run the tiller and run the tractor. And those pressures rule out any problems with the relief settings as well. If the pump was worn, then pressures would likely not exceed 1800 PSI. Even that much pressure would be OK to run the tractor and use the loader because the loader only need 1200 PSI max anyway. The only thing you might notice is a slight lack of push while going into a pile of dirt or stone but with some bucket wiggling, you would be able to get the bucket filled anyway.

The toughest job for the hydraulic system is usually roto-tilling in clay soils. All of the oil runs through the tiller motor and the pressures needed to spin the tines is often fairly high. Loader operation is not near as demanding and therefore will not generate the same amount of heat as fast as tilling will.

What you MAY have to do here is this.

Purchase a Tee fitting that can be inserted onto the PTO work port that supplies the oil to the tiller. In other words, you would have to do the following.

- figure out which hose to the tiller is the one that supplies the oil to the motor to make the tines spin in the direction you normally till in.

- remove the that hose or that quick coupler from the PTO valve and then put it back on but with the T fitting in between.

- connect the gauge to the T fitting with a hose long enough for you to see the gauge while you are operating the tractor.

- hook up the tiller and go till some really tough ground while the oil is still cold.

- bring that thermometer with you so you can check oil temps

- when you begin to till the soil, record the oil temp and the highest pressure you see on the gauge when the oil is still cool.

- work the tiller until you feel that the performance has dropped off.

- force the tiller into a standstill so you can record the highest gauge reading you see

- go check the oil temp and record it.

If you see a substantial drop in oil pressure along with oil temps that are 250 F or higher, then you have an oil breakdown issue in my opinion. The oil has lost its rated viscosity due to the high temps and has thinned out.

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kcunningham

· #20 · Apr 26, 2011

Next time it does it, check the suction line to make sure its not collapsing.

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