heymccall
Senior Member
I'd transpose the green and black and then retry (wheels off ground, of course).
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Hydraulic oil drain- now pilot controls won't work??
- Thread starter jav
- Start date
Bad news... seems like I jumped from the frying pan into the fire.
So I swapped hoses b & d at the pump. Started the machine and now not even forward /reverse is working. Plus the system sounds very strained and like a pail full of marbles. Clearly this was worse.
I immediately swapped the hoses back and now forward and reverse aren't working with the hoses back to to where they were before?. It seems like it could be air but I swapped the new hoses in dry and it never sounded like this and I only lost a little bit oil during the swap. The wheels do spin forward and reverse in low gear- not in high gear ( think I have the high gear solenoid unhooked so I'm not concerned about that) but- even in low- they don't sound smooth like they did before... not sure if its because the wheels are up in the air?
UUUUHHHGGGGG. feeling dejected and definitely don't want to do damage to the system. thoughts?
So I swapped hoses b & d at the pump. Started the machine and now not even forward /reverse is working. Plus the system sounds very strained and like a pail full of marbles. Clearly this was worse.
I immediately swapped the hoses back and now forward and reverse aren't working with the hoses back to to where they were before?. It seems like it could be air but I swapped the new hoses in dry and it never sounded like this and I only lost a little bit oil during the swap. The wheels do spin forward and reverse in low gear- not in high gear ( think I have the high gear solenoid unhooked so I'm not concerned about that) but- even in low- they don't sound smooth like they did before... not sure if its because the wheels are up in the air?
UUUUHHHGGGGG. feeling dejected and definitely don't want to do damage to the system. thoughts?
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heymccall
Senior Member
There is sufficient oil in the system, right?
heymccall
Senior Member
Could you be driving over the brakes? I dunno what kind of braking system is on there, but, does it have a separate hose and valve for braking?
How did you seal the system when hoses were off (did you leave a rag or plug in the system)?
How did you seal the system when hoses were off (did you leave a rag or plug in the system)?
brakes are electronic. Tied directly to lap bar and an e brake switch, Hydraulics can't be activated unless lap bar is down AND e brake switch off. I did not seal the system for the one swap. The fittings were right next to each other and are o-ring face seal fittings so both were loosened, one removed, the other removed and plugged right on to other port and then the first hose swapped to the empty port. Hose fitting face up so hoses stayed full of oil while the pump fittings dripped perhaps 8 ounces of oil during the swap. No plugs or rags used.
also during the wheel rotation, it seems like the wheels spin free then encounter resistance. Adding throttle can actually increase resistance. I hope I didn't booger the pump?
also during the wheel rotation, it seems like the wheels spin free then encounter resistance. Adding throttle can actually increase resistance. I hope I didn't booger the pump?
Thanks for the suggestions guys... got a good nights sleep and have a little clearer mind.
Heymccall- you may have been on to something with the brake.
In my post 7- item 9, i mentioned that after replacing all the lines, the machine was still leaking. After putting the machine up on blocks to try to work out any air and to try to relieve back pressure for pivots/turn- I was making no headway on that front and decided to look for the leak and I did find one solenoid that was leaking. I pulled that solenoid (which was in a group 4 solenoids and was attached to the manifold with 2 screws) to check the seal. I found that the bottom screw holding that solenoid was broken off in the manifold so the o-ring face seal was leaking at the bottom. I have to pull the whole manifold to drill out the broke screw and re-tap the hole. Not wanting to add another variable to my current woes- I replaced the face seal o-ring with one that was slightly thicker and put the solenoid back (with just the 1 screw) just to seal the hole and left it unhooked (electrically). I thought that solenoid was the high speed solenoid but just looked and it appears it's the brake solenoid... so you appear to be clairvoyant! Now- I re-plugged on the electrical connector and retried forward reverse but it's no different than with it unhooked BUT- I did loose some oil in that circuit when I pulled the solenoid and while it looks to have seated correctly in the manifold, I'm not sure if the thicker Oring is keeping it from "fully " seating. I think it might be possible that an air pocket in the line or manifold is preventing the brake from fully releasing and may actually be causing the high speed solenoid (also in the same group) to not actuate? Certainly if the brake is dragging, High speed may not work at all? it makes sense the brake may not be releasing. Any suggestions on bleeding those circuits?
Skata- No. I didn't replace any suction lines. Plus the only thing I changed from when the machine worked forward/reverse but no turn- was the solenoid mentioned above and swapping the b c lines. Nothing else was changed.
Heymccall- you may have been on to something with the brake.
In my post 7- item 9, i mentioned that after replacing all the lines, the machine was still leaking. After putting the machine up on blocks to try to work out any air and to try to relieve back pressure for pivots/turn- I was making no headway on that front and decided to look for the leak and I did find one solenoid that was leaking. I pulled that solenoid (which was in a group 4 solenoids and was attached to the manifold with 2 screws) to check the seal. I found that the bottom screw holding that solenoid was broken off in the manifold so the o-ring face seal was leaking at the bottom. I have to pull the whole manifold to drill out the broke screw and re-tap the hole. Not wanting to add another variable to my current woes- I replaced the face seal o-ring with one that was slightly thicker and put the solenoid back (with just the 1 screw) just to seal the hole and left it unhooked (electrically). I thought that solenoid was the high speed solenoid but just looked and it appears it's the brake solenoid... so you appear to be clairvoyant! Now- I re-plugged on the electrical connector and retried forward reverse but it's no different than with it unhooked BUT- I did loose some oil in that circuit when I pulled the solenoid and while it looks to have seated correctly in the manifold, I'm not sure if the thicker Oring is keeping it from "fully " seating. I think it might be possible that an air pocket in the line or manifold is preventing the brake from fully releasing and may actually be causing the high speed solenoid (also in the same group) to not actuate? Certainly if the brake is dragging, High speed may not work at all? it makes sense the brake may not be releasing. Any suggestions on bleeding those circuits?
Skata- No. I didn't replace any suction lines. Plus the only thing I changed from when the machine worked forward/reverse but no turn- was the solenoid mentioned above and swapping the b c lines. Nothing else was changed.
One pump per motor. 2 pumps 2 motors. The same lines (high pressure) per pump should go to the same motor, they shouldn't cross over. If you have forward and reverse, as it seems you have...….the steering part of the system is the reversing of the pump swashplate to gain oil movement in the pump and motor flowing the opposite direction. That is controlled by either pilot lines, or electrical signals depending on the type of system you have. I haven't seen very many systems that require "bleeding" of the lines themselves. Once there is movement of the oil from the pump, they will self bleed in most cases I have seen. I am wondering if you are too concentrated on the bleeding and overlooking what the actual issue is. JMO of course!
vetech63-
thanks for the input. I'm mostly focused on doing no harm. I'm not super knowledgeable on how these systems work so I'm doing a lot of reading and trying to "understand"... hence my color coded diagrams and frequent reference to the manuals and theory of operation, and asking for help here. I'm also waiting on an experienced tech to come by but every night, I try again- hoping to learn and maybe even have that AHA moment. Unfortunately, the manuals describe the functions of each component and in the case of the dual pump- it explains how 1 pump/swashplate works BUT doesn't explain the interaction of both pumps together to generate turns/ pivots. Also- after reading theory of operation, I come away with the same general understanding as many here- being 1 pump- 1 motor- no cross-over BUT- clearly the diagrams and my notes suggest otherwise.
And, in the back of my mind, I don't "think" the cross over is impossible because I would think the drive motor circuits can't be a "close loop"... in other words, there can't just be a supply/return directly from the pump to motors or the oil would eventually overheat... there has to be a bypass to send at least some of that oil to the cooler as well as a pickup to draw fresh cooled/ filtered oil back into the circuit... no? So from that standpoint- not understanding those cross flows leaves me guessing and certainly reluctant to presume the manual... and my notes are BOTH wrong, which is where I am now.
Also- not being super confident, I'm trying very hard not to change too much all at once... keeping the variables to a minimum. That solenoid thing is a good example of something I touched without "really" understand the possible impacts it could have. I thought I was just addressing a "leak" when now after at first dismissing Heymccall on the brake thing... his outsider thought process logically made me realize I likely caused the brake problem which means my b c swap test may have been invalid IF the brake circuit was not released!
I know its it more likely than not that I caused these problems but for the life of me, I haven't figured out what I did, or failed to do (yet).
thanks for the input. I'm mostly focused on doing no harm. I'm not super knowledgeable on how these systems work so I'm doing a lot of reading and trying to "understand"... hence my color coded diagrams and frequent reference to the manuals and theory of operation, and asking for help here. I'm also waiting on an experienced tech to come by but every night, I try again- hoping to learn and maybe even have that AHA moment. Unfortunately, the manuals describe the functions of each component and in the case of the dual pump- it explains how 1 pump/swashplate works BUT doesn't explain the interaction of both pumps together to generate turns/ pivots. Also- after reading theory of operation, I come away with the same general understanding as many here- being 1 pump- 1 motor- no cross-over BUT- clearly the diagrams and my notes suggest otherwise.
And, in the back of my mind, I don't "think" the cross over is impossible because I would think the drive motor circuits can't be a "close loop"... in other words, there can't just be a supply/return directly from the pump to motors or the oil would eventually overheat... there has to be a bypass to send at least some of that oil to the cooler as well as a pickup to draw fresh cooled/ filtered oil back into the circuit... no? So from that standpoint- not understanding those cross flows leaves me guessing and certainly reluctant to presume the manual... and my notes are BOTH wrong, which is where I am now.
Also- not being super confident, I'm trying very hard not to change too much all at once... keeping the variables to a minimum. That solenoid thing is a good example of something I touched without "really" understand the possible impacts it could have. I thought I was just addressing a "leak" when now after at first dismissing Heymccall on the brake thing... his outsider thought process logically made me realize I likely caused the brake problem which means my b c swap test may have been invalid IF the brake circuit was not released!
I know its it more likely than not that I caused these problems but for the life of me, I haven't figured out what I did, or failed to do (yet).
Welder Dave
Senior Member
Most systems are closed loop but have a charge pump and case drain. The charge pump also replenishes oil lost through the case drain(s). Not sure what your machine has but sounds like you need to get someone more familiar with your machine to come and look at it in person.
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Dave- wheels are VERY sluggish and resistant to turning.
Thanks for the info on the charge pump and drain... that fills in some gaps.
I Did some quick testing at lunch. Brake fuse is good. The brake solenoid is getting warm so I suspect it is getting power although I didn't have time to setup a probing method for the (female shrouded) connector to verify voltage. I cracked the pressure hydraulic hose coming from the brake solenoid output to the motors brake ports and there was no flow or pressure with the e brake switch depressed or released...so it would seem to me the brakes are not getting released hydraulically if they require pressure to release?
The next question is... is there no flow at the hydraulic line because the solenoid is not functioning OR because there's no supply pressure to the manifold itself?
I just looked up how the brakes release at the wheel motors and how the manifold gets supply pressure and it seems the motor brakes work via hydraulic pressure "RELEASEING" the brakes... they are normally engaged when there is no pressure- so the fact that no fluid is coming out of the line while cracked suggest the brakes are NOT disengaging.
On the solenoid group- here again the manual sections are conflicting and incomplete. On the theory of operation section for the valve group, it says the manifold galley gets pressure from pump port "E1" .. and ... When I trace that line on the schematic, it goes to a main pump port shown as "E2" (there is no "E1" on the schematic). Now- on the pump diagram- or on the pump itself, none of the ports are labelled at all so I can't identify either E1 or E2 . looking at the parts manual, the line does not run to the charge pump section but to a port at the top of the dual pump near the priming port. One odd thing about this upper part of pump is that the manual tells you to fill the pump cavity to the top to "prime" the pump. BUT- it seems like there is a return line somewhere that prevent the pump from completely filling up? I fill it till it overflows and it drains right back down to about 2-3" below the top. This port which send pressure to that manifold is right at the top so I could that air pocket be my problem?
Thanks for the info on the charge pump and drain... that fills in some gaps.
I Did some quick testing at lunch. Brake fuse is good. The brake solenoid is getting warm so I suspect it is getting power although I didn't have time to setup a probing method for the (female shrouded) connector to verify voltage. I cracked the pressure hydraulic hose coming from the brake solenoid output to the motors brake ports and there was no flow or pressure with the e brake switch depressed or released...so it would seem to me the brakes are not getting released hydraulically if they require pressure to release?
The next question is... is there no flow at the hydraulic line because the solenoid is not functioning OR because there's no supply pressure to the manifold itself?
I just looked up how the brakes release at the wheel motors and how the manifold gets supply pressure and it seems the motor brakes work via hydraulic pressure "RELEASEING" the brakes... they are normally engaged when there is no pressure- so the fact that no fluid is coming out of the line while cracked suggest the brakes are NOT disengaging.
On the solenoid group- here again the manual sections are conflicting and incomplete. On the theory of operation section for the valve group, it says the manifold galley gets pressure from pump port "E1" .. and ... When I trace that line on the schematic, it goes to a main pump port shown as "E2" (there is no "E1" on the schematic). Now- on the pump diagram- or on the pump itself, none of the ports are labelled at all so I can't identify either E1 or E2 . looking at the parts manual, the line does not run to the charge pump section but to a port at the top of the dual pump near the priming port. One odd thing about this upper part of pump is that the manual tells you to fill the pump cavity to the top to "prime" the pump. BUT- it seems like there is a return line somewhere that prevent the pump from completely filling up? I fill it till it overflows and it drains right back down to about 2-3" below the top. This port which send pressure to that manifold is right at the top so I could that air pocket be my problem?
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Well gents...the saga continues. Thanks for all the great insight and I'm actually feeling much more comfortable that I somewhat understand the system and I'm pretty sure my no turn problem is related to the motors crossing over between pumps... which means the manual and my note are wrong BUT before I can prove that, I have confirmed that the brakes are NOT disengaging by;
confirming that the brake solenoid is getting power.. but no oil pressure or flow is getting to the brake release ports on the motors. I pulled the solenoid, cleaned it, bench tested it and it worked.. meaning the spool moved when the coil was powered up. I re-installed it, tried it again and still no flow . Thea solenoid continued to get hot & leak through the case so I figured- bad solenoid.
I called Komatsu to get a new one... and they said the part number in my parts book is invalid, it may not be available and they said they would research it but they never called back. SO I pulled the MFG part number off my "bad" one and after much research, I found a very similar one locally at a supply house. By very similar I mean -same manufacturer, same base part number, same body, same dimensions, same function (3 way - 2 position) same voltage, same connector... but the komatsu version has a diode in the coil and this one does not and there is something "proprietary" about my exact part number that belongs to Komatsu and they would't tell me what it was BUT... as far as the MFG was concerned, the alternate I found "should" function exactly the same but for a possible voltage spike back fed to the wiring when the coil de-energizes. I bought it and installed it... no change... still gets hot - still not output pressure.
SO- I got out my pressure tester, fashioned the appropriate adapters and tested pressure out of the pump into this 3 valve manifold. 375 PSI which was in spec. Reconnected the line and tested pressure out of the solenoid output port. 0 PSI energized or de-energized... no output. so I pull the solenoid and as soon as the screw thread releases, the solenoid shot out under pressure (there is an accumulater on the manifold block).
SO -I pull the output line at the brake motor and using compressed air, blew it back towards the manifold (with the solenoid removed) and the line is clear. I started the engine and oil shoots out the solenoid hole.... thats clear. I put the new solenoid back in, tighten it up and retry the output test and again- no output pressure. I re-verify voltage... it's 14V. SO it would appear the solenoid is NOT opening??? BTW- i confirmed the solenoid is rated to work unto 650 PSI. on ports 2 & 3 (work, pump) and 50 psi on port 1 (return). I suppose there could be something structurally wrong inside the manifolds solenoid bore but WTF am I missing? Tomorrow i may check if perhaps the tank return is getting pressurized above 50 psi?
there is no manual override on the solenoid or would have tried that.
thoughts?
confirming that the brake solenoid is getting power.. but no oil pressure or flow is getting to the brake release ports on the motors. I pulled the solenoid, cleaned it, bench tested it and it worked.. meaning the spool moved when the coil was powered up. I re-installed it, tried it again and still no flow . Thea solenoid continued to get hot & leak through the case so I figured- bad solenoid.
I called Komatsu to get a new one... and they said the part number in my parts book is invalid, it may not be available and they said they would research it but they never called back. SO I pulled the MFG part number off my "bad" one and after much research, I found a very similar one locally at a supply house. By very similar I mean -same manufacturer, same base part number, same body, same dimensions, same function (3 way - 2 position) same voltage, same connector... but the komatsu version has a diode in the coil and this one does not and there is something "proprietary" about my exact part number that belongs to Komatsu and they would't tell me what it was BUT... as far as the MFG was concerned, the alternate I found "should" function exactly the same but for a possible voltage spike back fed to the wiring when the coil de-energizes. I bought it and installed it... no change... still gets hot - still not output pressure.
SO- I got out my pressure tester, fashioned the appropriate adapters and tested pressure out of the pump into this 3 valve manifold. 375 PSI which was in spec. Reconnected the line and tested pressure out of the solenoid output port. 0 PSI energized or de-energized... no output. so I pull the solenoid and as soon as the screw thread releases, the solenoid shot out under pressure (there is an accumulater on the manifold block).
SO -I pull the output line at the brake motor and using compressed air, blew it back towards the manifold (with the solenoid removed) and the line is clear. I started the engine and oil shoots out the solenoid hole.... thats clear. I put the new solenoid back in, tighten it up and retry the output test and again- no output pressure. I re-verify voltage... it's 14V. SO it would appear the solenoid is NOT opening??? BTW- i confirmed the solenoid is rated to work unto 650 PSI. on ports 2 & 3 (work, pump) and 50 psi on port 1 (return). I suppose there could be something structurally wrong inside the manifolds solenoid bore but WTF am I missing? Tomorrow i may check if perhaps the tank return is getting pressurized above 50 psi?
there is no manual override on the solenoid or would have tried that.
thoughts?
well i don't think the solenoid spool is moving to the on position but there is 14V at the solenoid connecter AND there is 375psi at the manifolds pressure port but there is no flow or pressure at the solenoid output port. For some reason the solenoid is NOT directing the pressurized oil out to the output port when its energized. Last nite I had the thought that perhaps the connecter has voltage but maybe when I plug it onto the solenoid, the connectors female contacts aren't effectively transferring the voltage onto the solenoid male pins? While I think that would be possible- I do feel the relay body heating up when it's energized so It is my belief that this heat is from the electrical energy and not from hot oil since because I usually try this right after startup so the oil probably wouldn't get that hot that quick?? But I'm trying to think of anything and everything to explain whats going on?
Todays plan- confirm with the Hydraflow (the manufacturer) that the solenoid does for sure have the 12vdc coil (which they said it did yesterday but like everything else- i take nothing for granted) and... I'm going to machine up a spool to put in place of the solenoid that will temporarily connect the manifolds pressure port to the brake output port so I can confirm that when the brakes get hydraulic pressure, they release and that the motors spin in forward/reverse freely...getting back to where i was about 5 days ago.
Todays plan- confirm with the Hydraflow (the manufacturer) that the solenoid does for sure have the 12vdc coil (which they said it did yesterday but like everything else- i take nothing for granted) and... I'm going to machine up a spool to put in place of the solenoid that will temporarily connect the manifolds pressure port to the brake output port so I can confirm that when the brakes get hydraulic pressure, they release and that the motors spin in forward/reverse freely...getting back to where i was about 5 days ago.
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Check the coil on your solenoid. It may be getting power but not working. The easiest way to tell is to remove the nut holding the coil on the valve stem, then make sure it has power to it. It should feel magnetized to the stem if working properly when it is under power and grounded properly..
Vetech-
this is the solenoid... it's not the typical stem cartridge with removable coil.
I did confirm the coil resistance at 7.6 ohms (same as my other one) and I can feel that the Housing is getting warm. Also- power and ground are applied at the connector so the body doesn't need to be grounded for it to work.
this is the solenoid... it's not the typical stem cartridge with removable coil.
I did confirm the coil resistance at 7.6 ohms (same as my other one) and I can feel that the Housing is getting warm. Also- power and ground are applied at the connector so the body doesn't need to be grounded for it to work.