Perplexed
 

A while back Eric and I bought a 2072 that had been repowered with a command engine, a 18 hp. The hydro seemed strong and it had power to spare. The power steering was another story. It was not working.
What we have done so far:
Changed tranny oil and filter
Fixed a couple of leaks in hydro with new seals and a new gasket.
Replaced the two valves on top as one was leaking.
Just replaced the steering column and steering cylinder with a known good one
Still no power steering.

The hydro unit works great to drive the tractor, infact it outperforms both our 2084 and 2086 but we just cannot find out why it does not work the power steering What are we missing here. We are fresh out of ideas.

Paul, how does the lift work? As in, will it lift a deck, blade ect? (If it has 3pt this is an easy test.)

Did a steel line get kinked during engine installation? Or crossed perhaps?

How is the Hydro System plumbed or piped..?? Anything change...??

Sounds to me like the power steering cylinder is in need of a rebuild.

He tried that to no avail :bigthink:

Wish I could contribute more but I don't have a lot of experience with PS systems. About the only suggestion I could offer is make sure the lines are bled but even this, it should still at LEAST work.

Yes the tractor has a 3 point and it is slow but works. I did not see any kinked or altered lines but then again was not looking for that. I drove it this morning and It seems to be just a tiny bit better after the col and cyl change but is certainly not working any where near the way it should.

My 2072 was stiff and not feeling right after rebuild this spring. Terrible when first starter after steering rebuild to check for leaks. After finishing tractor moved outside to warm up steering felt a bit better. Used for a few minutes and now works great. One finger steering again. That was 30 hours ago. Hopefully your does the same.

The hydraulics are very slow and it hasn't had power steering since we've owned it. And as far as I can tell the line's are where they are supposed to be .

Kinda sounds like a pump problem. Can you check the system pressures?

Oak I was thinking the same thing. I will have to see who around here may have the tools I can barrow.

I did usde it for a couple of hours today till it got too hot and still no power steering. So far as I know I have no way to check the pressure. The hydro drives the tractor excellent and I was presuming the same hydro unit also pressures the lift and steering. Correct me if I am wrong.

Paul, there is an implement relief valve that could be causing your problem. If all the hydraulics are slow on the tractor but it drives fine maybe that is whats wrong. I not 100% sure as I never had to tear into one yet but maybe some of the other guru's will chime in.

Todd right there is the problem but I'm not sure how to fix it either!

You need to do a pressure check. You should be able to borrow/rent a gauge set for testing pressure for automatic transmissions at a parts store. Otherwise, go to a hardware store, and buy a 1000 PSI gauge. Then pull the plug for the relief valve and take it and the gauge to a place that makes hydraulic hoses. Have a hose made that will screw into the port, and the other end to accept a gauge. Let us know what you find. If you haven't done it, I'd really do looking the lines over to see if any are either twisted at a fitting, or kinked. Look everywhere. PS handpump, valve stack, and the pump. I really think that it is a flow, not a pressure problem, but I'm not there to see it, so I'm just going by description. :beerchug:

This tractor does have a 3 point rear lift. I checked and yes it is quite slow. I weigh about 170 - 175 lbs and raised the arms part way and with me standing on it it went down but would not go up. Could that be a pressure problem. This tractor seems to be the same as my 2084 as far as the hydro goes except for possibly the way a rear lift hooks up on the 2084.

It's definitely a pressure problem. If the 3pt won't pick you up, yes.

Question first: You said you were using it today till it got too hot. What got hot? Outside temp (too hot for you?)? Or the hydro?

No, the 2084 is plumbing is different than the 2072...... kinda. They use different spool valves, but if you understand hydraulics, they are the same. So, you can't compare them by "looks".

You need to know what pressure the system is running at. But, even then, you may not know if it is a relief valve problem, or a charge pump issue. I suspect at this point there is a charge pump problem. However, a simple pull-and-clean of the relief valve is probably where I'd start.

It is letter "C" in the pic. There is an o-ring on the cap I'd replace, other than that, pull it and make sure there is nothing stuck in it. You need to find a way to "flush" or clean out the hole too. The oil may drain out of it, (I can't remember if it will or not). Just make sure there is nothing in the hole. (Dirt, or debris.) Make sure that the poppet (#20) is not grooved, or marred. If it is, it's bad. If not, then you have a pump problem.

Attachment 52900


Come back and let us know what you find. If you need to look into the pump, I can help with that too. Sent you a PM too. :beerchug:

When I reread my post I realized I did not define "it got too hot" It was not the tractor it was the weather. In central PA we do not get many 90 degree days and yesterday was one of them. A further description of this tractor may be in order. In addition to what I have already said this tractor has the front hydro ports. everything is 2072 except the engine and drive shaft which we had to have made due to length difference. Most likely this tractor will not be used for mowing purposes although it came with a 60 inch haban deck and a 451 snow blower. At the moment it has a Johnny Bucket Jr mounted to the front this has no affect on the hydro as they are electrically operated. As mentioned before we have had the tractor split a couple of times for leaks and initial cleaning. The fluid that was in it was quite bad. We drained and cleaned the tranny initially and even drilled the drain holes in the axle tubes that Sam Mac suggests because both were filled with fluid and water when we took them apart. We at that time did not replace the filter but refilled the tranny with new fluid and ran it for over a month and then again drained the fluid, replaced the filter with a cub cadet hydro filter and filled it with fluid. As I said the tractor drives excellent. Absolutely no slow down going up hill or speed up going down hill. I will look for the relief valve mentioned just to see if I can find it. This tractor has been ridden hard and not even put away wet but suspect left outside wet but we are close to having what we want with this beast. Jumping into the hydro side of this tractor has been a little intimidating as neither Eric or I know much about hydros and their operation.

Sounds good Paul. I have not torn into the relief valves on one yet either so were gonna need lots of pictures. I have a busted super pump on one of my tractors. If I get a chance tonight I will pull it and take some pics for you guys and if you need it I can send it to ya.

What is busted about it. We may be interested.

Sorry guys but since I posted about our problem I have notices a whole bunch more posts about hydro problems. Sure hope I did not wake up a sleeping beast with my post.

Ok Jon, I put a gauge on the hydro tonight and the best I can get pressure wise is 100 psi. We have not dug into the valves but at this point would it make a difference if we did or not? Thanks for the help so far guys.

Yuk. 100 PSI is way off. Hey, do you think the rear has been changed? I only ask because of this thread. Might be worth the time to make sure it has both valves. Otherwise, pull the relief valves. Not the big ones mind you, the little ones. Check that thread out I linked to. I put pics up in it. I'm lazy and don't want to post them again. :biggrin2:

Jon as far as I can tell this rear has not been changed and it has both of the needed valves so if dad doesn't pull them tomorrow I will do it after work, thanks.

Cool. The one on top is the one you need to pull. Since it drives fine, the one on the side shouldn't be bad/issue. I have a feeling that it may be the charge pump. Here's for hoping for you!! :beerchug:

If it's a splined pump from a super it will (should) have both valves, but who knows what the PO did.:bigthink:

Could your charge pump cover be on 180* wrong? Here is how it should look. I'm not sure it could be put on wrong but maybe.
Attachment 52967

Are you guys 100% sure all the power steering lines are on correct?

Ok here goes nothing. Oak our pump is splined and does appear to be mounted the same way as the one in your pic. The stamped name is on top and possibly a part # can be seen on the bottom.

Jonathan I very carefully and with a little trepidation removed the top relief valve. I removed the hex headed top which has an O ring at the top of the threads under the hex head. This part has a hollow core and appears to be good without any scratches or undue worn spots. Next came about an inch long spring also appearing to be in good shape albeit a really stiff puppy. The last piece to come out is the cup which is squared on the top and a tubelike appearance with a cone shape on the bottom. it too seems to be in good shape. I did not see any shims as described in the description though. My thoughts are leaning toward the pump or the unlikely tube attached to the wrong place. I am going to try to get my camera working and take some pics but at the moment the camera had dead batteries.

You can rotate the pump 180°. And I too still wonder about the lines being crossed. Todd, maybe you can post a pic of the line routing? I don't have a super to take pics of.


Sounds like all is well in the valve. And if there are no shims, then you can't remove any and see if it helps..... so.... I am going to lean toward the charge pump also. Eric says it is only make 100PSI. I only have one question: Is that 100 PSI just idling? WOT? And at any point in the test did you try to "max out" the pump? In other words, hold one of the hydraulic levers (until all movement stopped and it started whining) during the test? Might try that and see what the pressure does. I'm with OAK. Make absolutely sure that there are no crossed lines before proceeding. If you sure they are right, pull the charge pump and lets have a look.

We first tested at what I would call a high idle and the guage needle did not move. We were testing using the forward, toward the front, hole that had a plug in it. I saw on another forum that Roland used the rear hole more toward the middle of the top. When we raised the engine speed to at or near full throttle we got the approx 100 psi reading but it seemed to bleed off some. I say approx because our guage reads to 4000 lbs and the diff between the 100 lb marks isn't very much. We did not try a load test but could do that tonight as it is still set up to test but with the top implement relief valve removed. The guy that made up the guage for Eric said he has tested thousands of hydros and always used the plugged hole to do it. I am also thinking it is in the pump but we are going to trace out the lines again tonight. Many thanks for your help. Would the pump from most other hydros fit this hydro. We looked at the hydro in our 149 and it appears to be identical.

Paul, no, only a super pump will work. The output shaft is different on the SGT's. I don't think this will help but it only takes a minute. When I rebuilt my steering box I had no steering at all. I ran it for 5 minutes and had nothing thinking I put it together wrong. I loosened the hose going to the steering ram and moved the wheel back and forth a few times and it started working. Give that a try maybe you'll get lucky.

Todd, I think Paul was referring to the charge pump.

If so, yes. All charge pumps are the same. :beerchug:

Yes I should have known that the shaft would not hook up. I guess I am picking at straws due to the expense of the pump. I thought all along that maybe there was air in the system as I cannot conceive of how the system can purge itself especially the steering cylinder. Will do some more testing and looking tonight but my hopes are dimming. Will the pump from the one you have fit our needs.

The one I have is completely ruind. The shaft is damaged and the po machined out the charge pump trying to repair it. Have you contacted Rich?

We changed guages to one that max's out at 600. We first tried in the top implement relief hole and got no pressure at all. We then switched to the middle hole between the hydro valves on top this hole just has a plug in it. There we got about 180 at idle and got about 340 at full throttle. There was no difference in pressure when we operated the rear lift lever or turned the wheel. We also rechecked the plumbing and all seems good there.

I'm sure the charge pump is bad. You might go ahead and pull it off and just make sure it isn't something that can be easily fixed. Like a broken o-ring on the back, or the small key on the shaft.

Ok will do but why do you not answer your phone. Lol I suppose you don't want to talk

Not sure if this was solved, but I just did a power steering unit rebuild on my 2072 and had a similar problem. I was very meticulous and assembled it according to the service manual.

I got it all back together and had no power steering, no hydraulic lift. I finally figured out the picture I had drawn of the hydraulic lines was drawn with all four wheels on the ground. I reinstalled everything with the tractor vertical (front wheels up in the air) and must have drawn my picture upside down. Somehow, I had the lines switched. Switched them to the proper placement and the it immediately worked.

However, the hydraulic cylinder for the mower deck works fast when raising the deck, but very, very slow when lowering now. Still trouble shooting that one.

Yes my 2072 hydro problem(s) have been solved. We had hooked up all the lines exactly the same way they were when we got it. As it turns out we had two lines reversed also. At the time I was having computer problems and could not download the pics I needed to be sure I had things hooked up properly. When I did get the pic of the routing diagram of all the hydro lines found out that the pressure line and the return line were switched. Switched them to their proper locations and viola we had power steering and working rear lift. The power steering is fantastic when using the Johnny Bucket. My rear lift seems to be working well also. We lowered it and I stood on the lift arms and it lifted me like nothing. Right now it sits in the garage partially dismantled to fix a hydro leak at the cork gasket where it meets the tranny. Did you try to hold up the arms while lowering them with the hydro. It sounds like you are not getting hydro down power. Check that line for kinks and be sure it is hooked up properly.

Another thing to check is make sure your levers are centered in the dash cutout. If you don't get the spool valve in the same location you won't have as much travel in one direction with the levers.

As a final note after we got the system fixed we had a different hydro unit and it was leaking. We replaced the cork gasket as that is where it was leaking and after all the work to replace it we still had a leak. Yesterday we took it apart again and replaced the cork gasket again using the black sealant and that darn thing still leaked at the gasket. As a very last resort we replaced the hydro with the one that was in it when we got it. This time we used the ultra grey sealant and after assembly had to wait till this evening to try it. I filled the tranny and temp hooked up the battery and fired it up. I tested the whole works and everything operates and after about 5 minutes shut it off and no leaks. We may have solved our problem but still have no clue why one hydro leaks and the other does not. Both are out of a 2072.

More than likely, it wasn't the gasket that was leaking.

On a side note, you shouldn't need to put any sealant on that gasket. Cork gaskets are meant to be installed dry. My experience: they only leak it if isn't installed dry. Sometimes even with sealant (silicone) they will leak. Reason: it makes the gasket slick and it "slides" out when compressed instead of smashing like it's supposed to.

I hope you didn't plug the hydro drain hole with silicone...... :bigeyes: