TMS300 slow hydraulics

I bought another TMS 300 recently. The previous owner had knocked off the drain plug on the hydraulic manifold at the pumps. We welded the drain plug back on and filled it with hydraulic fluid. We opened the 4 bleeders that are on the 4 pipes as they cross over the top of the transmission. We also burped the air out of them at the top of the pumps. When we operate the crane, it seems like all the functions are very slow compared to our other TMS300. They all work but I have to rev the engine to max rpm to get it to operate like our other one does at idle. This crane had been sitting for 6 years before we started messing with it. Every function is equally slow so it seems very unlikely that all 4 pump sections would go out at once. The guy I bought the crane from had some sudden health problems and had to quite working without notice. He had told me it was working fine before sitting and so far has been 100% up front and honest with me. I pulled the filter and it looked good. I have a new one on the way regardless. Any idea what might be causing our low hydraulic output?

So the pumps were sitting there with no oil in them, and exposed to air for the six years it was sitting still? If so, I can see a rebuild of the pumps in your future. Tolerances are pretty tight on those, and a layer of rust wouldn't be impossible, with that amount of time exposed to air on them. It shouldn't be too expensive to have them rebuilt, or even new pumps.

Just of another question, what's the oil look like? Even if the tank was empty, there's another 150 gallons out in the cylinders, that you wouldn't have gotten out from just changing what's in the tank.

Are both cranes the same engine?

I run mine wide open most of the time, unless I'm trying to just crawl the winch, and my outriggers won't work unless its up in rpm's either.

Its also possible that six years of sitting has the seals pretty flatspotted and/or hard. They could be allowing fluid past the seals. If that's the case, the boom raise and lower cylinder, would allow the boom to creep down with any stick out at a lower boom angle.

I'm sorry I wasn't quite clear on the details. Both cranes are 855 cummins. The crane has been sitting that long but about 1.5 years ago they loaded it onto a low boy to move it and knocked off the drain plug from the hydraulic manifold. The oil looked great as did the filter. I'm going to pull it again now that I've run it and change it. There was still a film of oil inside the manifold. I had to clean it to weld the drain plug back on. When we went to bleep the air from the manifold, there was still oil in the pipes where they turn down to the pump sections. My outriggers will work on my other TMS300 at just above idle but not all the way down. I really should fix the hand throttle in the other crane. I do tree work with mine so most of the time we are using it, it's sitting there waiting on someone to put on rigging or make a cut. The boom wasn't leaking down at all. The swing, the winch, the boom, outriggers, and telescope are all super slow. I won't be surprised if I end up having to build or buy pumps. I was kinda looking for other things to check before doing that. I'd hate to build the pumps to turn around and still have the same problem. I guess I could swap the pumps from my other crane but that seems like a big pita and then it would be down as well. I need to dig through the service manual some more and see if there is a pump pressure test procedure.

"Working fine" may mean it's been slow as long as he's had it and not had another crane for comparison. Is there a main relief valve in the valve body and all of the functions go through it? It could be stuck partially open or the seals on the valve are bad and dumping fluid and killing your GPM on the pump. I doubt all sections are damaged from sitting because you said there was oil present. I would check for a stopped up suction screen feeding the pump first. Also oil viscosity to be sure it's correct. Does it operate faster with cold oil and slow down as it warms up? And do you have any idea of how many hours are on the crane? It may be a worn pump.If it was used in a high cycling operation like steel erection the pump could be suspect.

tractormech said:

"Working fine" may mean it's been slow as long as he's had it and not had another crane for comparison. Is there a main relief valve in the valve body and all of the functions go through it? It could be stuck partially open or the seals on the valve are bad and dumping fluid and killing your GPM on the pump. I doubt all sections are damaged from sitting because you said there was oil present. I would check for a stopped up suction screen feeding the pump first. Also oil viscosity to be sure it's correct. Does it operate faster with cold oil and slow down as it warms up? And do you have any idea of how many hours are on the crane? It may be a worn pump.If it was used in a high cycling operation like steel erection the pump could be suspect.

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There isn't really a "main" relief valve, because different sections of the pump, drive different functions. It allows the operation of multiple functions smoothly. So one section does boom, another the swing, and a different section the winch. Fluid is filtered as it returns to tank, there isn't a suction screen either.

I'd plumb in a pressure gauge into the boom and winch, and see what kind of pressure the pumps are putting out. I wouldn't change pumps from one crane to the other, by the time you pull them, you just as well rebuild them, or at least have them pulled apart to see what they look like.

I've not worked on one of these specifically so I'm not aware of how it's plumbed. It being a multiple section pump leads me to think the pump is worn. It will make pressure but the GPM is shot so it's slow. I wouldn't bother swapping pumps either-no need to down one to check the other. Pulling the pump apart will tell the tale. I pulled one on a tm 275 and it was getting slow-opened it up and it was worn completely out.

These guys owned three other grove cranes of similar size so I doubt they didn't know how they were supposed to operate.

It's so slow it's almost unusable. I'm going to pull the filter and swap the new one in so I can get a good look at contaminates. I looked at the filter prior to starting it up.

I also looked for a main pressure relief valve wondering if it was stuck from sitting. Thanks for the info on the suction screen. I was wondering if something might be caught in it.

I take it I can tap into the 4 npt plugs right above the transmission for each circuit then dead head them to test the pump output? I found a PSI chart for each in the manual last night but ran out of time to keep looking through for a test procedure.

We used AW32 hydraulic fluid as that's what the local grove dealer told us they use in our climate. I ran it about 20 minutes as it was pretty jerky from all the air trapped in it. It seemed the same the whole time. It was about 55 degrees out. The boom is as slow down as it is up. The winch seems to operate at close to regular speed. The outrigger extensions went out but now won't come back in. I haven't put a load on anything as I just sat the pads down. I was trying to change the oil as it's been 6 years since the engine has had an oil change. We normally put our other TMS up on it's outrigger and lift the nose to get room.

Thanks for trying to help me.

So I got some time this afternoon to work on this some more. The outriggers section would only build 600 psi at wide open throttle with the outriggers valve in operation. Looks like I'll be tearing the pumps down for a look. Is it better to just buy the whole pump or just the sections, bearings, oring kit, and gears? I'm very mechanically inclined but haven't ever had to build a gear pump. I have blind bearing pullers, presses, regular pullers, and a full machine shop at my disposal.

I don't know how old your machine but the may be a magnet cluster in the hydraulic tank. Check and see and if it does pull it and have a look. I'd check pressures at all ports coming out of the pump and see if they're all low on pressure. I assume you checked the outrigger pressure at the outrigger. 600 is very low....suspiciously low. You need a hydraulic schematic so you aren't fumbling in the dark. It will take all the guess work out of relief valves,screens and what feeds what at what pressure. The other gentleman (crane operator) said there wasn't a suction screen so check other things as well. Are the suction hoses rubber? They should have wire in them to keep them from collapsing. Look at the pump itself-does it look discolored like it's been hot? If so pull it and tear it down. All the seals and o rings could be burnt up and you have no pressure. Look at the housings the gears run in and see how worn it is-if it 's scored up at all you need a pump. Do all your checks first before you pull the pump.

2000 psi is where the pressure relief is set. We pulled our grapple truck up next to the crane and did some replumbing as we needed to get it up on its outriggers to do some other work to it. I did pull the filter and put the new one in. There was a very tiny amount of metal in the filter. I would expect more from four failed pump sections. I also pulled the drain plug at the bottom of the manifold at the pump. It flows a nice stream out of it. The pumps appear perfect from the outside. Most of the piping from the tank to the manifold is hard line. There are some short sections of hose. It was wet out today and raining some so I didn't crawl under the crane to look bit In going to. I'm going to pull the pumps at some point and tear them down for inspection if nothing else. They are both seeping pretty bad so resealing them wouldn't hurt anyway if it proves to be a restriction on the intake side. I also verified the tank vent wasn't clogged up. I won't be surprised if I get in there and find out over time condensation got into the pump and rusted it. The top of the hydraulic tank in bolts. I was thinking about pulling it of and make sure something isn't stuck in the outlet.

Right-but 4 sections of pump would I think require 4 relief valves since each section powers a different part of the crane-wouldn't you think? Just a thought-I wouldn't think the outrigger supply runs through the swivel.....or does it? A blown swivel will leak pressure between the ports and kill the pressure. There's a lot of unknowns here. You said it put the outriggers out but won't bring them back. Maybe when the oil is cold it's thick enough that the pump will make "some" pressure but when it thins it's a no go. How old is this rig?you said it has an 855 Cummins-An old Big Cam? Mechanical motor with no electronics? That's an old unit if so. That may point to a million hours on the pump and it's worn out. I hate to condemn the pump though until everything has been checked out.

If its only making 600, I could see it not wanting to pull the outriggers back up, it doesn't hardly have enough pressure to overcome the holding valves.

I've had some pumps apart, but haven't rebuilt one. I bought a whole new pump for one of my boom trucks for under $2000 (If I'm remembering right). Those pumps aren't hard to pull, with the top cover off, you have all kinds of room and access. You can pull it apart if you want, but I wouldn't rebuild one myself. My last pump came out of memphis. I can find their number if you need it.

I hope you won't see much metal, because then its in everything in the system, you'll never get it all out. I'm just hoping the pumps have too much wear in them and won't make pressure.

I doubt there's any restriction in oil flow to pumps, that's a huge line supplying it, a squirrel could crawl down it.

I wouldn't unbolt the tank cover if you don't have to, unless you really want to look in it.

They are a pain to reseal, and the bolts tend to break off- they rust inside the lid, and you can't pull the rusty bolt through the lid threads.

Ate the valve spools moving the whole way

That's a good question Tyler asked-check pilot pressure to see if it's in spec to operate the spools in the valves (If pilot operated)

tractormech said:

That's a good question Tyler asked-check pilot pressure to see if it's in spec to operate the spools in the valves (If pilot operated)

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I had a machine that was linkage controls that the spring caps got dirt in there but it was very obvious as the levers would only move a tiny bit.

There are 4 different pressure reliefs. I got some time to dig through the manual some more. They are all set at different pressures. We hooked a hydraulic circuit from our grapple truck into the outrigger circuit but blocked it off going to the pump. It was no problem to operate the outriggers at all. The pressure relief for this circuit is working fine. The outriggers don't run through a swivel on this crane. It wouldn't bring them back in immediately after pushing them out. I think Crane Operator is onto something with not making enough pressure to open the holding valves. I didn't want to knee jerk to condemn the pump especially since the PO told me everything was working fine. Spool valves are working fine.

I'm going to pull the pumps out at some point and tear them down. I want to go ahead and order a seal kit before I do that. Crane Operator, If it's not a big pain, I'd like the number of the folks you got the pumps from.

Thanks,
John

I replaced both pumps on my Tms300 in October. They were $1740.00 each right from Walter Payton.

Price your seals and other replacement parts and compare them to the price of a new pump. I know this is high priced crane parts. The last couple of (non crane) pumps that needed attention I replaced, as soft parts were about 50% of the price of a new pump.

John Griffin said:

I'd like the number of the folks you got the pumps from.

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Sorry John, I forgot to call him today, I'll try and get their number tomorrow.