No power steering on a Terramite

[cstamm81]

ok, this tractor has one drive pump that bolts right to the rear end, no individual wheel motors. I would definitely inspect the drive pump as a potential source of problems. I will also clean the reservoir, strainer, and change the filter. Is there any chance of the source of contamination being in any of the following : steering unit that has the diverter valve inside of it, any hydraulic or return lines, or any hydraulic cylinders? I'm very paranoid now, I have to make the decision to spend a large sum of money to fix this. So, I want to be 100% sure I do not have any issues after installing the new or rebuilt pump. Besides disassembling every single cylinder and hose (ie anywhere that hydraulic oil flows through) how can I be sure of myself? Ahh, gotta love buying someone else's nightmare off of ebay...

 

[wdchyd]

the only thing I'd be paranoid about cleaning would be the the drive motor, reservoir, filters and suction hoses & screens and the hoses connecting drive motor to the pump

The steering components, cylinders will have some kind of return filter so any contaminates will be caught there before they return the oil back to reservoir ........unless the oil is milky (water), shiny silvery (suspended metal), or severly dirty I wouldn't worry too much about it

If you can put a few magnets in the reservoir that may help when you do your first oil change after the breakin to help visualize any steel particles floating around......I don't think it's necessary to disassemble everything....maybe go a little overboard with filter cleanliness for the first few hours of run time

We use a filter cart when running into catastrophic pump failures.......after a complete cleaning, reassembly, new oil......we use the filter cart to help filter the oil while it is running at idle, sometimes we'll run it for an hour or so

 

[cstamm81]

alright well I need to call Terramite and compare the price of new vs rebuilt. Then beg my wife to allow me to sink money into a tractor I did not need lol. I really appreciate all of the guidance with this, I will post up when I decide to buy or rebuild...
By suction hoses do you mean any hoses returning to tank, or just the larger diameter low pressure hoses? As for strainers, are they inside the suction hoses or how are they attached? I want to verify they are clean and intact. Previous owner had changed this hydraulic oil the year before, said he had maybe 25 hrs of run time after that. System calls for 15W40 and he had 10W30, but it looked very clean, no metal visible and no water present. Maybe the pump damage occurred many years ago.

 

[wdchyd]

Maybe the pump damage occurred many years ago.

Yes......
Most people do the clean and flush when the troubles first rear it's ugly head......hoping.......

but the damage has already been done and what you are doing is the best way......I've always said "Better to know what the problem is and not be able to do something about it, than not know what the trouble is from the start"

It's the reason why I preach to keep the oil & filters like new as an insurance policy.....it's not a garrantee of no troubles, but rather if you don't keep the oil clean it's a garrantee you will have troubles eventually

 

[the old grind]

Going back a ways ... if the pressure test going into the steering box showed low, the 'box' hasn't really been tested under proper circumstances. Could it be no more than possibly contaminated as routing from the bad pump might allow up to this point? ... only a symptom of the bigger problem?

Disassembly of the dated box itself is intimidating, to say the least. This pic is about all that's available to any who'd dare to juggle its pieces on the bench. The 4 bolts that hold the column on hold the rings, manifolds, and covers together as well. T-M's tech offered to talk me through removing the bolts when I was ready, and with his guidance keeping the stack of goodies together to replace #29 here:

.....

Seeing the innards of this oldie I can imagine a couple of extra hands or a really good setup to hold onto things. What I'm getting at is ... if there is no obvious junk in its line/inlet does it look like it can just be flushed out and (fingers crossed) given a shot as is or perhaps bench tested with a 'remote' supplying input (catch bucket outlet) and with the cylinder attached? (input pressure critical??)

I sincerely apologize for jumping so far ahead of the process, but with decision$ to be made the 'package' and the OP's resolution will come into focus soon enough. Others may encounter steering or pump issues, and this could be helpful in so many ways. This is good stuff ...

 

[wdchyd]

This pic is about all that's available to any who'd dare to juggle its pieces on the bench. The 4 bolts that hold the column on hold the rings, manifolds, and covers together as well. T-M's tech offered to talk me through removing the bolts when I was ready, and with his guidance keeping the stack of goodies together to replace #29 here:
.

A tip:

before you guys take apart ANY hyd steering unit (or hyd pump or motor) you need to take a small grinder and slice a line up the side of the housing to help orient the parts when you put it back together

these units have multiple sections that need to go back exactly the same way

:2cents:

 

[wdchyd]

Going back a ways ... if the pressure test going into the steering box showed low, the 'box' hasn't really been tested under proper circumstances. Could it be no more than possibly contaminated as routing from the bad pump might allow up to this point? ... only a symptom of the bigger problem?

You make a good point Old Grind

a hyd system is just that ....."a system"......it takes many parts to make it function, one weak link and it won't work right.....if pressure is low then nothing works downstream

kinda like working on an electrical system.....if you have problems with an elec motor, you wouldn't be tearing down the motor without checking the electrical power coming in,right??.....or checking the switch that operates it too

Troubleshooting, whether it is an electrical or hydraulic system is the most important part of repair work.....and I always said "How can you fix something if you don't know how it works".....this type of trouble will at least educate the tractor owner with understanding of how it works

 

[the old grind]

A tip:

before you guys take apart ANY hyd steering unit (or hyd pump or motor) you need to take a small grinder and slice a line up the side of the housing to help orient the parts when you put it back together

these units have multiple sections that need to go back exactly the same way

:2cents:

Thanks! On mine I'd be going for an absolute minimum of disassembly of the 'housing group' and just pulling #31 & up (jacket, shaft, upper cover etc) to swap in the new seal per T-M's advice and with their help. (that's my own deal for later(!) if I can get the s-wheel off & the column-box out, lol) & OT for now!

Wdchyd, with all the help you've been (99%?) I don't want to put you on the spot for the 'right' answers to all this. It'd be great if fixing the OP's pump was enough by itself (I call that 'wishful dreaming'). If others should go all thru' this possible 'fountain' of confusing little pieces to decontaminate a 'box' it could get deep and require a qualified professional like yourself going hands-on. IMO you deserve much more than smileys and thank you's for your assistance, already! (sincerity, not sarcasm, ok?)

I'd rather the OP wasn't the guinea pig for the rest of us T5C owners, but it seems to be new territory and if so there has to be a first. There's just so much inside a s-box box that'd have to go back together exactly right, as you've said earlier. Other than code stuff, plumbing & electrical do seem like childs play by comparison.

 

[wdchyd]

hydraulics is childs play too.....just sometimes more expensive.....:thumbsup:

Over the years I've come to the conclusion that hydraulics is either easy fixes or catastrophic fixes.....experience is the best teacher

hopefully talking this stuff out will bring out some questions and answers for others too

 

[cstamm81]

Ok, spent some good phone time with two different guys from TM today (one is a member on here). I can get the whole assembly, hydro trans, charge pump, gear pump apparently brand new from Eaton (sold through TM though) for about $1600. So not much more than having the old one rebuilt. I also asked about the torque motor as mine has two broken off ears and that is another $600.

TM service told me I might want to push the cylinders closed to force fluid out of the hoses, change filter, strainer and should be good to go. He kept saying anything I push back into the tank will not come back through due to the strainer. He mentioned cycling fluid through the torque motor if I do not replace. I asked but he did not say anything about the steering as being a concern, I believe he mentioned that the oil would be filtered / strained after going through the steering system and before returning to the pumps? Does this make sense?
the old grind, you bring up a great point and my cause for concern. IF I can justify dropping 1600 - 2200 on this, I NEED to assure myself that I have checked and double checked everything before installing brand new pumps. I love learning new things and doing my work myself, but with this amount of money I wish I knew someone locally who could help me assure myself of a problem free install.

I wish I knew the history of the tractor, but my best guess based on overall condition is that this thing lived a hard life. Hydraulic shop thought something significant must have gone through that pump to tear it up so badly. My job would become to make sure there is nothing still in the system to hose me again.

 

[wdchyd]

Hydraulic shop thought something significant must have gone through that pump to tear it up so badly. My job would become to make sure there is nothing still in the system to hose me again.

When the significant stuff went through the pump did it go through the barrel and get caught between the face of the barrel and the valve plate?

Did it look like it went where the red and blue oil goes in the pix?.....or did it look like the piston slipper/shoes were torn up instead?

 

[cstamm81]

thread revival... I am not sure where the significant stuff went through, the hydraulic shop did not specify. They only said there is significant damage, and it as very far from normal. I spoke with them again today and they are telling me they will rebuild the whole thing for under 1200 and bench test the assembly. He is telling me he will be replacing the whole rotating group, sealing everything. Said he will check out the aux rear pump but said it looked fine. Mentioned something about a rear cover being gouged, but said it will be replaced. No written warranty, more of a gentleman's agreement if by chance they would assemble something wrong.
I mentioned the torque motor with the damaged mounting flange and he wants to take a look at that to make sure there is no potential internal damage. My guess is I would be in the neighborhood of 1500 to have them inspect and rebuild everything, and I could get it all brand new for 2200 plus shipping from Terramite. Decisions decisions...

 

[cstamm81]

In an effort to think through potential issues if I pull the trigger on a rebuild or replacement... I want to verify operation of the initial issue, lack of power steering. My fear is there is ALSO something going on in the steering box / diverter valve. Or, and maybe this is far fetched, the steering circuit has not had operating pressure running through it for who knows how long, so who knows what to expect when the pressure is restored with the new/rebuilt pump.
So, being as I have another perfectly operating Terramite T5C in my possession, I got to thinking. Would it be possible or advisable to try the following: Disconnect the power steering line from my working tractor and plumb it into the steering box of the non working tractor. Run the working tractor and check for proper steering operation / leaks on the non working tractor. I know this will drain fluid from the working tractor and return it to the tank of the non working tractor. I had even thought of catching the oil returning to tank in a container for evaluation, seeing as the steering circuit has not seen full pressure in awhile. It is time to change fluid in the working tractor anyway, and I am assuming I could run it for a minute or two easily before running the reservoir level down enough to starve the pump.
So, is this a good idea? Is there anyway I'm missing as far as system pressure on the working tractor? I am not sure how the charge circuit works, but the last thing I want to do is create a problem on the working tractor.

 

[wdchyd]

Sure, that will work.......you could catch the return flow in a clean bucket to replace it in the donor tractor or run a temp hose back to donor

At work we have a hyd power unit with variable flow/pressure and many times we have done this exact thing......at least you will be able to set your mind at ease when you test out the steering circuit

as far as the rebuilt stuff, replacing the rotation group is the right way to do it, but in my mind if the repaired/rebuilt goes beyond 60% you should be cautious, they should give you some kind of warranty (which would likely be void if they find contamination damage anyway)

 

[cstamm81]

I am going to try and get to the hydraulic shop in the next week or so and see the damage myself. His best guess is the damage may have been caused by over-speeding of the pump? He did not believe it was due to metal going through, but was really only guessing. I mentioned the system calls for 15w-40 motor oil, and asked if damage could have been caused by someone using hydraulic oil instead. He seemed baffled why Terramite would call for 15W-40, said that universal tractor fluid covers most systems. Mentioned that if hydraulic oil and oil were mixed it would be a no no. Comment was he and his worker have been doing this each for 15 years and have not seen anything quite like this. I do wonder if a different shop could do the same rebuild for much less $$$.

I spoke to him about the damaged torque motor, and he did not believe he could rebuild it and replace the broken mounting flange section for much less than the $600 TM wants for a new one.

 

[J_J]

It is hard to believe that a good hyd shop did not know about the use of motor oil in hyd systems.

 

[cstamm81]

that struck me as a little odd as well. This SEEMS like a well run, established place. I only found it based upon a recommendation from a guy I respect, but that's all I know about the place. He did mention some Bobcats (I think) call for straight 30 weight oil, he just didn't seem like he knew why OEM's would call for motor oil in the systems.
Terramite warns in big letters on the first page to not use hydraulic oil, as pump damage will result. I do wonder if the severity of the damage to the rotating group could have been caused by a previous owner using hydraulic oil in the system.
I had entertained having the shop throw the pump back together and I would reinstall as is, as the machine did operate (without power steering and some obvious pump issues) before I took it apart. The guy told me he was surprised the tractor moved with the pump in such poor shape, and mentioned it may develop decent pressure with the oil cold but as it warmed it would most likely lose pressure. So it sounds like that idea is down the toilet (and silly in the first place).

 

[wdchyd]

It is hard to believe that a good hyd shop did not know about the use of motor oil in hyd systems.

most industrial systems don't use motor oil but rather 10w (ISO-VG32) and 20w (ISO-VG46) so it doesn't surprise me they didn't know......it seems the only time we see motor oil is when the manufacturer uses components that are over heating ( reservoir too small or components working too hard) and worry about the oil being too thin accelerating wear on internal parts

ZTR mowers are a good example, they run hot and don't get oil cool enough

 

[ChippyMcGee]

I read this thread about a month ago when I was looking at a 1990 T5C that I thought had a power steering problem. Turns out the 1990 model has manual steering (no power steering from factory). I bought the machine and it has trouble with forward and reverse. If I go forward or reverse slowly, there is no problem - plenty of power and smooth. If I try to go faster in forward or reverse, the motion is jerky and erratic, as if a chain was slipping (I know there's no chain). I found online the Eaton Service Manual for the variable displacement hydraulic pump model #70142 (aka hydrastatic transmission) - (see link below). It says to check the charge pump pressure at the charge pump access plug (i.e. remove the plug and connect pressure gauge) on bottom of pump. Haven't done this yet since I don't have a new o-ring to replace when reinserting the plug. Anyways I wanted to pass along the link to manual. I believe you can order the "Adapter Plate" that was mentioned earlier from Eaton - just find the manual for your pump (hydrostatic transmission as Terramite calls it) on that we page, get the part number and order it from Eaton/Vickers.

http://www.vickershydraulic.com/site/pdfs/07-623.pdf

 

[ChippyMcGee]

P.S. - From what I read, and as others have mentioned, the power steering pressure comes from the charge pump output, which should be between 100 - 300 PSI. The Eaton manual says that you can check charge pump pressure at the port (after removing plug), but it's probably the same pressure you'd measure at the power steering line. The manual also says that if charge pump pressure is low, then check charge pump pressure relief valve, which I believe is what others found to have pushed through its seat in the adapter plate. Manual says if charge pump pressure is low but relief valve checks out OK, then "replace pump and motor."