Oliver 1755 Hydraulic Issues

Alright, first, a bit about the tractor. It's a 1971 model with a gas engine. It has a loader on it, which is T-ed into the hydraulic line that runs around the back of the seat for a supply and then returns to what used to be a plug to the left of the filler tube.

The pump whines a bit, like it's low on fluid. According to the fill tube, it's not low. It acts like it is pumping fluid all the time, and it heats up quite a bit, and does so very quickly, even if the tractor does nothing but sit there and idle.

So, we tried to check the compensator valve. We removed it (Why does everyone seem to think this is hard?) and cleaned it. It seemed free to begin with, and cleaning it made no change. We cleaned both the spool in the valve itself and the spool in the main valve body.

Then we removed the low pressure valve. It looked brand new. We cleaned it off and replaced it. Nothing changed.

We stopped the tractor, and opened to air bleeder again, then fired it back up. When I held the loader valve in the "curl" position, the noise nearly went away. In any other position, it made noise.

In checking for other times when this noise went away, I turned the wheel all the way to the left. After doing this, the wheel will not turn right! Is this related to the original problem, or is it due to being turned too far left?

I've got a pressure gauge on the way, but it's not here just yet.

What else could it be? In another thread, someone mentioned that the 3-point arms should have 1 to 1.5 inches of travel (I assume this means in addition to slack in all the joints?), even when it's fully raised? If that's the case, then this may be our problem. Our 3-pt lift arms are solid when they are fully raised. There is no give in them at all...

Thanks!

You said: The pump whines a bit, like it's low on fluid. According to the fill tube, it's not low. It acts like it is pumping fluid all the time, and it heats up quite a bit, and does so very quickly, even if the tractor does nothing but sit there and idle. It probably is pumping and since it is closed center it should not pump!. You also said: So, we tried to check the compensator valve. We removed it (Why does everyone seem to think this is hard?) and cleaned it. It seemed free to begin with, and cleaning it made no change. We cleaned both the spool in the valve itself and the spool in the main valve body. Why does everybody take these items apart without making in leakage or pressure checks? Do you have a serial number which is more important than the year. Since you ordered a gauge, get yourself a needle valve as well so you can make some checks Do you know if your steering is still a Saginaw unit or if is a Char lynn unit?

It probably is pumping and since it is closed center it should not pump!

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Yes, agreed. It's nice to have some confirmation.

Why does everybody take these items apart without making in leakage or pressure checks?

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See above. (Also, see numerous threads on this topic which suggest this.)

Do you have a serial number which is more important than the year.

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Serial: 226-855-676
Model: 675-21025

Since you ordered a gauge, get yourself a needle valve as well so you can make some checks.

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What, exactly, will this allow me to check? I can't see any reason for this. If I get one, where will it be connected, I'll need to know what size to get it in...

Do you know if your steering is still a Saginaw unit or if is a Char lynn unit?

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I do not. I will try to check in the morning. (The steering walks, so I believe it's a Saginaw.)

I had a loop line made up so I could warm up thee system and use it to check compensator setting as well as detent operation of the remote valves as well as relief valve settings. You will need 2 spare male couplers in addition to a hose and the needle valve plus a high pressure pipe tee and a short pipe nipple. I used a half inch needle valve and a 1/2 inch hose about 2 feet long. Do you have a book(shop manual) You need to measure case drain leakage for sure as well as making these pressure checks. do you have a phone number? J.

If your relief valve pressure is too low the compensator will not kick the pump into neutral and oil will go over the relief causing heat. You need to adjust that. It will in time also walk the gasket out.

We have an I&T manual, but not Oliver manual.

We have the gauge, but no hose. We have some fittings, but not the ones to tie into where we'd like to (the T that supplies the loader valve), however we have enough allow us to hook the gauge into a remote (but not make a loop).

Does checking the pressure at the remotes work well? It is my understanding that the remotes have independently adjustable valving?

We do not have the needle valve yet, but if we need that to get the fluid warm, that's not a problem! We can just let it idle for a few minutes...

Call 903.539.6990 and speak with Larry.

Which of the relief valves are you speaking of? The high pressure or low pressure one?

Sorry for the delayed response. Verizon had a tower go down, or a line get cut, or something (I didn't really understand their announcement...) and we've been without reliable service for over a week now...

Anyway, we've made good progress!

We had to wait on parts to be able to check our pressures, but we got them in and should be able to do that soon.

We did discover two things in our previous work, and we've fixed the main issue (overheating) already. Now we just want to get the fine-tuning right with the pressure gauge...

So the two things we found to be an issue were the 3-pt lift arm adjustment and the compensator valve.

The compensator valve appeared to same some gunk in it, so I'm sure that didn't help, but the main issue was that the previous owner had screwed it in ALL THE WAY! So, it was simply set too high and never letting the pump shut off. We adjusted it so that it lifts the 3-pt at idle and left it there until we can get the actual pressure readings. You can hear the pump shutting off now.

The second issue was the 3-pt lift arms. They were adjusted too high (there was no upward free-travel). We adjusted them down a bit, and now we can hear the relief valve working when they reach the top.

So, between those two issues, we've eliminated the overheating problem. We still need to fine-tune the settings and get the right pressures, but we think we've about got it all sorted out.

(J., sorry for the disconnected/dropped call the other day. Like I said, there's been poor signal here. We're very appreciative of the help!)