Sorry I keep asking so many questions. I just want to do it right and also don't want to make anything worse. I'm really nervous about running it with the supply to the pumps disconected since I just spent $3000 having the pumps and motors rebuilt. Would it help any to cap the case drain line? Would it hurt anything? The flow meter is rated for 3500 psi and the highest gauge I have is 4000 psi. Would these work between the pump and motor?
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It should only take a matter of a few seconds to determine if you can get more than 3gpm. Do not cap the case drain. If you are not comfortable doing this then let's look at another alternative. If you place a tee between the hose and pumps and place a gate valve and hose at the tee, you can leave the gate valve closed and run the pumps without any issue. Opening the valve should increase the gpm and still supply oil to the pumps as long as the charge pressure does not drop to zero. All we need to see is if the gpm goes up..........Your flow meter and gauge should work fine as long as you do not put a heavy load against the hydro motors, such as engaging the parking brake. Since you will probably check with the engine at a low rpm and the machine blocked up, it should not take much pressure to rotate the motors. Just move the lever enough to get the motors barely rotating and watch the gauge for fluctuations.Sorry I keep asking so many questions. I just want to do it right and also don't want to make anything worse. I'm really nervous about running it with the supply to the pumps disconected since I just spent $3000 having the pumps and motors rebuilt. Would it help any to cap the case drain line? Would it hurt anything? The flow meter is rated for 3500 psi and the highest gauge I have is 4000 psi. Would these work between the pump and motor?
Ok. I ran the machine with the flow meter before the pumps and the parking brake on. 3gpm in neutral but when I stroked the left lever forward the flow would go up. It would go to 10 GPM If I really pushed it.. Reverse stroke met more resistance and flow would stay at 3 unless I really pushed hard, then it would go up. The right side was opposite. Flow up to 10 in reverse and forward offered more resistance. However when I really pushed it on the left It would make a loud awful sound from the motor or possibly chain case.It should only take a matter of a few seconds to determine if you can get more than 3gpm. Do not cap the case drain. If you are not comfortable doing this then let's look at another alternative. If you place a tee between the hose and pumps and place a gate valve and hose at the tee, you can leave the gate valve closed and run the pumps without any issue. Opening the valve should increase the gpm and still supply oil to the pumps as long as the charge pressure does not drop to zero. All we need to see is if the gpm goes up..........Your flow meter and gauge should work fine as long as you do not put a heavy load against the hydro motors, such as engaging the parking brake. Since you will probably check with the engine at a low rpm and the machine blocked up, it should not take much pressure to rotate the motors. Just move the lever enough to get the motors barely rotating and watch the gauge for fluctuations.
Well, at least we know it is capable of flowing oil. When the relief valves open it should flow more oil which is what you saw when it went up to 10gpm. The increase should come from the pump case drain. You might disconnect the case drain from the hose and install your hose you used earlier to check the case drain flow into a bucket just to make sure that is where the increased flow is coming from.......When you had it on the ground and were driving it did the right side seem to drive smoother in forward than it did in reverse and did the left side drive smoother in reverse?Ok. I ran the machine with the flow meter before the pumps and the parking brake on. 3gpm in neutral but when I stroked the left lever forward the flow would go up. It would go to 10 GPM If I really pushed it.. Reverse stroke met more resistance and flow would stay at 3 unless I really pushed hard, then it would go up. The right side was opposite. Flow up to 10 in reverse and forward offered more resistance. However when I really pushed it on the left It would make a loud awful sound from the motor or possibly chain case.
Well it always seemed like the left was worse. Maybe just because I was moving forward more than backbackward. I thought about disconnecting the hoses from the motors and plugging them and then checking the flow again. That would remove the motors from the equation. I hadn't thought about the relief valves opening and that increasing flow. What could that horrible nose have been? I assumed this was proving that the motors are the problem, but I didn't think about the relief valves.Well, at least we know it is capable of flowing oil. When the relief valves open it should flow more oil which is what you saw when it went up to 10gpm. The increase should come from the pump case drain. You might disconnect the case drain from the hose and install your hose you used earlier to check the case drain flow into a bucket just to make sure that is where the increased flow is coming from.......When you had it on the ground and were driving it did the right side seem to drive smoother in forward than it did in reverse and did the left side drive smoother in reverse?
I shouldn't say it suddenly shoots up to 10 gpm. When the brake is on and the lever is stroked it just moves up quickly to 10 gpm. Not sure if that makes a difference.Well it always seemed like the left was worse. Maybe just because I was moving forward more than backbackward. I thought about disconnecting the hoses from the motors and plugging them and then checking the flow again. That would remove the motors from the equation. I hadn't thought about the relief valves opening and that increasing flow. What could that horrible nose have been? I assumed this was proving that the motors are the problem, but I didn't think about the relief valves.
I plugged the hoses to the motors and checked the flow into the pumps. The flow was less than 3 gpm in neutral and it did not go up when I stroked the levers. When I stroked the levers the hoses would go stiff and the flow meter would shake a little and I could hear the pumps straining. I didn't push the levers very hard really because I figured out what I needed to know. Both the motors are bad. When the motors were hooked up the flow would go up to 10 gpm and over when I'd stroke the levers with the parking brake engaged. I called the shop that rebuilt them and they agreed that I need to bring the motors back in. So now I gotta decide if I want to mail them in or make the 6 hour drive to hand deliver them. He said if I plan ahead and get them there first the in the morning that they could rebuild them that day while I wait. Is there anything I could gain by going there? I guess I could see just exactly what they do.I shouldn't say it suddenly shoots up to 10 gpm. When the brake is on and the lever is stroked it just moves up quickly to 10 gpm. Not sure if that makes a difference.
Another quick update. I removed the motors this weekend. It took about 2-3 hours this time (took about 10 hours last time). Boxed them up and shipped them out. Hopefully I'll know something by the end of the week. They said they can't load test these motors so I am a little nervous that I might get them back next week and run into the same problem. I'm not sure what went wrong the first time they rebuilt them. We'll see I guess. Thanks. BrettI plugged the hoses to the motors and checked the flow into the pumps. The flow was less than 3 gpm in neutral and it did not go up when I stroked the levers. When I stroked the levers the hoses would go stiff and the flow meter would shake a little and I could hear the pumps straining. I didn't push the levers very hard really because I figured out what I needed to know. Both the motors are bad. When the motors were hooked up the flow would go up to 10 gpm and over when I'd stroke the levers with the parking brake engaged. I called the shop that rebuilt them and they agreed that I need to bring the motors back in. So now I gotta decide if I want to mail them in or make the 6 hour drive to hand deliver them. He said if I plan ahead and get them there first the in the morning that they could rebuild them that day while I wait. Is there anything I could gain by going there? I guess I could see just exactly what they do.
You might question them on their procedure on shimming the motors. It has been awhile since I did one, but I think from NH there is a special collar in the seal kits so the motors can be shimmed correctly. The procedure is in the service manual.Another quick update. I removed the motors this weekend. It took about 2-3 hours this time (took about 10 hours last time). Boxed them up and shipped them out. Hopefully I'll know something by the end of the week. They said they can't load test these motors so I am a little nervous that I might get them back next week and run into the same problem. I'm not sure what went wrong the first time they rebuilt them. We'll see I guess. Thanks. Brett
One thing you can check when the motors come back is the rolling torque of the motor shaft. You install a bolt in the end of the motor shaft and take an inch pound torque wrench and rotate the motor shaft shaft and see how much torque it takes to keep the shaft rotating. The initial breakout torque will be higher but the torque required to keep the shaft rotating should be no more than 60 in/lbs. It may be slightly higher since you are supposed to check the torque without the seal installed. A beam type torque wrench works the best.You might question them on their procedure on shimming the motors. It has been awhile since I did one, but I think from NH there is a special collar in the seal kits so the motors can be shimmed correctly. The procedure is in the service manual.
I think I could turn them by hand pretty easily after I took them out. I assume that's bad.One thing you can check when the motors come back is the rolling torque of the motor shaft. You install a bolt in the end of the motor shaft and take an inch pound torque wrench and rotate the motor shaft shaft and see how much torque it takes to keep the shaft rotating. The initial breakout torque will be higher but the torque required to keep the shaft rotating should be no more than 60 in/lbs. It may be slightly higher since you are supposed to check the torque without the seal installed. A beam type torque wrench works the best.
You may have been able to turn the shaft with the gear on the shaft, but it should not have been easy.I think I could turn them by hand pretty easily after I took them out. I assume that's bad.
The shop tore them down again and he found a hairline crack in the piston block on one of them. Said the wear surfaces look perfect and everything fits tight. He is replacing both the piston piston blocks thinking that the other may have a crack that he couldn't find. Sounds promising to me -- I think.?You may have been able to turn the shaft with the gear on the shaft, but it should not have been easy.
Update. Finally got around to putting the machine back together after the shop put new piston blocks in the motors. I first fired it up with it still up on jack stands and the flow meter inline just before the hydro pumps. I was getting less than 3 gpm with the levers in neutral. Then as I would stroke the levers the wheels would spin and it would stay under 3 gpm. I then engaged the parking brake and tried it again. Still remaining below 3 gpm -- good news. Looks like it is working. Take it down from the jack stands and it runs great. Ran it for about 30 minutes or so with no problems at all. The only thing that seems strange to me is that the charge pressure gauge I ran to the cab with a 6 foot hose reads 150 psi at start up and it does move down after the oil warms up. At the end of the 30 minute use it was down to 120-125 psi. It ran great even at that pressure and the charge light doesn't come on until it drops to 50 psi. I wonder if the gauge could be wrong. Also I know that the pressure switch leaks oil slowly -- doesn't seem to leak enough to effect charge pressure that much though. The service manual says the charge pressure should be 150-190 psi. Any ideas?The shop tore them down again and he found a hairline crack in the piston block on one of them. Said the wear surfaces look perfect and everything fits tight. He is replacing both the piston piston blocks thinking that the other may have a crack that he couldn't find. Sounds promising to me -- I think.?
If the light stays out I would not worry about it. The l555 will flicker the charge pressure light when using the loader hard such as when moving and operating the boom and bucket at the same time. Glad you finally got things straightened out. One other thing that might be causing low charge pressure when hot is the oil you are using. All oil may come out of the ground, but the refined product can be vastly different in performance and how it holds up with the increase in temperature. It is not unusual for pressures to drop when hot, that is why all tests should be done when the unit is at operating temperature. A leaking pressure sender should be replaced. The leaking sender should not effect the charge pressure but can give false indications of low charge pressure.Update. Finally got around to putting the machine back together after the shop put new piston blocks in the motors. I first fired it up with it still up on jack stands and the flow meter inline just before the hydro pumps. I was getting less than 3 gpm with the levers in neutral. Then as I would stroke the levers the wheels would spin and it would stay under 3 gpm. I then engaged the parking brake and tried it again. Still remaining below 3 gpm -- good news. Looks like it is working. Take it down from the jack stands and it runs great. Ran it for about 30 minutes or so with no problems at all. The only thing that seems strange to me is that the charge pressure gauge I ran to the cab with a 6 foot hose reads 150 psi at start up and it does move down after the oil warms up. At the end of the 30 minute use it was down to 120-125 psi. It ran great even at that pressure and the charge light doesn't come on until it drops to 50 psi. I wonder if the gauge could be wrong. Also I know that the pressure switch leaks oil slowly -- doesn't seem to leak enough to effect charge pressure that much though. The service manual says the charge pressure should be 150-190 psi. Any ideas?
I just thought I'd post a follow up. I have been using the L555 off and on. It has been running great. I will be changing the hyd oil and filters again soon and I plan to change the charge pressure sender also but I'm considering the idea of not replacing the sender and just running a gauge instead. In fact I think I might mount a 3 gauge pod in the cab that has charge pressure, engine oil pressure and engine temp. Is there any reason I shouldn't? I would also like to thank everyone on here that has helped me along the way with figuring out how to get this machine running. And of course a special thanks to Mike10 because as usual he helped me the most.If the light stays out I would not worry about it. The l555 will flicker the charge pressure light when using the loader hard such as when moving and operating the boom and bucket at the same time. Glad you finally got things straightened out. One other thing that might be causing low charge pressure when hot is the oil you are using. All oil may come out of the ground, but the refined product can be vastly different in performance and how it holds up with the increase in temperature. It is not unusual for pressures to drop when hot, that is why all tests should be done when the unit is at operating temperature. A leaking pressure sender should be replaced. The leaking sender should not effect the charge pressure but can give false indications of low charge pressure.
Now I'm concerned again. I ran the L555 for a couple hours today. It ran great. But as I was pulling it back into the garage the Hydraulic charge light came on. It was still running fine. I'm not sure what's up. I have a gauge in the cab that give real time readings for hydraulic charge pressure. It was reading 130 - 135 psi while I was pulling the machine into the garage. The manual says that the charge light will come on when the charge pressure drops below 50 psi. So why would this light come on when the charge pressure is 130 psi. Also of note is that when the machine would not drive properly (especially turning and under load) the charge pressure light was not on. Do you think I have a bad pressure sender?I just thought I'd post a follow up. I have been using the L555 off and on. It has been running great. I will be changing the hyd oil and filters again soon and I plan to change the charge pressure sender also but I'm considering the idea of not replacing the sender and just running a gauge instead. In fact I think I might mount a 3 gauge pod in the cab that has charge pressure, engine oil pressure and engine temp. Is there any reason I shouldn't? I would also like to thank everyone on here that has helped me along the way with figuring out how to get this machine running. And of course a special thanks to Mike10 because as usual he helped me the most.
Well I feel like an idiot. Just a couple posts up Mike10 said that a leaky charge pressure switch could give a false reading of low charge pressure if it leaks. Mine does leak, so is it reasonable to assume that is what's going on since the gauge was reading 130 - 135 psi (what it always says after warm up). I was planning to change the pressure switch when I changed the oil and filters again so maybe I'll just do all of that a little early. The manual says to change the filters at 20 hours after a hydrostat rebuild. I am going to change the filters and the oil because my oil is still a little milky from the previous water infiltration I had when the local sholp left the machine out in the rain without even bolting down one of the chain case inspection plates. One last thing is that I have a small hydraulic leak somewhere that leaves a drop of oil on my garage floor when I pull the L555 back in after use. I think it is one of the hoses that I disconnected and reconnected about 100 times over the last few months because it didn't leak at all before. Does anyone have any tips on how to hunt down a leak like this or should I just start disconnecting and reconnecting things again? ThanksNow I'm concerned again. I ran the L555 for a couple hours today. It ran great. But as I was pulling it back into the garage the Hydraulic charge light came on. It was still running fine. I'm not sure what's up. I have a gauge in the cab that give real time readings for hydraulic charge pressure. It was reading 130 - 135 psi while I was pulling the machine into the garage. The manual says that the charge light will come on when the charge pressure drops below 50 psi. So why would this light come on when the charge pressure is 130 psi. Also of note is that when the machine would not drive properly (especially turning and under load) the charge pressure light was not on. Do you think I have a bad pressure sender?
The only real way to find a leak is to give it a good wash then hunt.Well I feel like an idiot. Just a couple posts up Mike10 said that a leaky charge pressure switch could give a false reading of low charge pressure if it leaks. Mine does leak, so is it reasonable to assume that is what's going on since the gauge was reading 130 - 135 psi (what it always says after warm up). I was planning to change the pressure switch when I changed the oil and filters again so maybe I'll just do all of that a little early. The manual says to change the filters at 20 hours after a hydrostat rebuild. I am going to change the filters and the oil because my oil is still a little milky from the previous water infiltration I had when the local sholp left the machine out in the rain without even bolting down one of the chain case inspection plates. One last thing is that I have a small hydraulic leak somewhere that leaves a drop of oil on my garage floor when I pull the L555 back in after use. I think it is one of the hoses that I disconnected and reconnected about 100 times over the last few months because it didn't leak at all before. Does anyone have any tips on how to hunt down a leak like this or should I just start disconnecting and reconnecting things again? Thanks
Change out the oil, if it is white, get it clean. Even if you flush it with cheap oil first, run it for a little while then dump and put in your final stuff.
That pressure sounds good, i'd bet it is just a bad sender, why not hook up a T piece and have both a manual gauge and the standard setup? May be more effort than it's worth, but you can at least take it back to normal later if desired.
Thanks Tazza. I'll get hunting as soon as I can. It is only leaking about a teaspoon a month. Actually I'm already running on the cheap oil after draining the oil that had water in it. My plan was to go 20 hours and then change the oil along with the filters. Now I guess I'll be changing the charge pressure switch also. I'm at about 10 hours since the rebuild. I also have a tee at the charge pressure switch with a 6 foot hose running to the cab. So I already have both a gauge and the warning light. I'm glad I had both going or I would be freaking out again thinking that I'd be tearing the hydrostat back out again.The only real way to find a leak is to give it a good wash then hunt.
Change out the oil, if it is white, get it clean. Even if you flush it with cheap oil first, run it for a little while then dump and put in your final stuff.
That pressure sounds good, i'd bet it is just a bad sender, why not hook up a T piece and have both a manual gauge and the standard setup? May be more effort than it's worth, but you can at least take it back to normal later if desired.
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