I Have a Komatsu Pc35mr-2 S/n 8438 My Swing and Travel Are Sloe Written By Malik Therymare Sunday, May 8, 2022 Add Comment Edit I recently bought a used PC35 with about 3,000 hours on information technology. I knew that it had this issue when I bought it, and I got an appropriate discount, only at present information technology is time to diagnose and repair. I am very handy, but take zero experience with this kind of hydraulic equipment. The car works fine when it is cold. Just once it warms up, ie once the temp approximate rises off the peg to a normal operating temperature (I have not measured the exact temp at which this happens, and I don't know if it is engine temp or hydraulic fluid temp that matters), the engine will stall if whatsoever hydraulic role is run to the limit and held there even briefly. ie, when cold, the chief relief valve and related relief components seem to work fine, just when hot, something doesn't work right and the engine stalls. I checked the idle and total throttle RPM, and they are to spec. The first diagnostic footstep in the shop manual is to check the Master Relief Valve, so as suggested I measured the relief pressure when this happens, and the pressure rises to about 24 Mpa just before the engine stalls. Main relief force per unit area spec is 26. So that seems ok - I presume that the failure style is when the relief pressure is too loftier. My next move, based on the store manual diagnostic flow for "Engine stalls", was to measure the differential LS pressure. When I started to look into doing that, I discovered a bunch of aluminum foil stuffed between the muffler and the master hydraulic pump. That led me to dorsum to the shop manual, which shows (in pics) the muffler covered in some kind of insulation. That insulation is missing from my muffler. And office of the principal hydraulic pump that contains the LS parts is closest to the muffler. Has anyone seen anything like this? Does the heat shield/insulation on the muffler seem important, of import enough to cause part of the hydraulic pump to overheat if information technology is missing? Any hints, suggestions or guidance - esp of the form, "Oh aye, every PC35 that I have ever seen has this issue when..." would be near appreciated. John C. Senior Member Joined: Jun 12, 2007 Messages: 10,947 Occupation: Machinery & Equipment Appraiser Location: Northwest You might consider giving a series number so we take and idea of which Dash series auto y'all have. I've never had to spend whatever fourth dimension working on the Komatsu minis so possibly someone volition come along with better insights. As fas as the heat shield for the muffler goes,it is kind of important as the estrus will bake the insulation on the wires going to whatever electric components. The heating problems usually started with the coolers and radiators which were non piece of cake to clean on standard machines and is fabricated exponentially worse on mine exes. Everything is tight and the counterweight many times has to be removed for access just to blow the dust out of the fins. Every bit far as the hydraulics stopping the engine go, that shouldn't happen at all. As I think, virtually of those machines had a unmarried piston pump and a gear pump on the dorsum that ran the blade and peradventure the swing but I'thou not certain of that. I call up I have a manual somewhere only won't know if it applies to your automobile unless yous post a serial number. Does the cab on your machine tilt for admission to the control valve? Cheers for the reply John. Series # is 09865. Auto is a PC35MR-ii . Canopy, no cab.This machine appears to accept a single pump, with a single piston, but information technology has two output ports. I exercise not believe that there is a 2d, separate, hydraulic pump. The trouble occurs when any hydraulic function, including travel, is used to the limit. The cab does tilt for admission to the control valve. Delmer Senior Member Joined: Jan 4, 2013 Letters: 7,394 Location: WI I've never seen a PC35 then I'll leave that to John C, he seems to be the best answer you lot're going to get on some of those. You might be barking up the wrong tree looking at the hydraulics first. This isn't a large excavator with a more complicated hydraulic system with lots to go wrong, and lots of "optimization". This volition be relatively crude and simple. How nearly the fuel organisation? What does the engine practise when it stalls? sputter? dark smoke? no smoke? will it recover right away if you allow off soon plenty? or does information technology seem like information technology merely switches off? I don't know that fuel system either, merely I'd be looking for a croaky condom fuel suction hose, or a plugged banjo bolt screen. John C. Senior Member Joined: Jun 12, 2007 Messages: 10,947 Occupation: Mechanism & Equipment Appraiser Location: Northwest My source shows your auto to be an MR1 simply information technology may be wrong which would mean you take a gray market place car. My source says there were no MR2 machines sold for domestic employ in the U.s.a.. I"ll meet what I have for reference material and get back to you. The data plate and placards are in English language, which is no guarantee but suggests that the original destination market was the US. Also, I know this machine was owned by a local municipal authorities originally, which again argues against grey market. I can mail service a picture of the information plate if that would be useful. John C. Senior Member Joined: Jun 12, 2007 Letters: 10,947 Occupation: Machinery & Equipment Appraiser Location: Northwest All information plates for Komatsu that I have seen in the past dozen years have been in English. PM me your email address and I can ship you a link with some information. The motorcar does have a single piston pump that has the ability to act like a double pump and it does have a gear pump mounted on the back of the piston pump. At that place were MR-ii machines sold here. It is possible someone messed with the controls on the pump or that there may a problem in the main control valve LS circuits. Expect for broken paint on lock basics for the pump and valve controls for clues apropos tampering. My first instinct was fuel or air too! But the shop transmission wants me to diagnose the hydraulics beginning, and my gut says that that is consistent with the actual behavior of the machine. That said, I had a generator with too much oil in the crankcase, and it would die in just this same way if you asked it to produce 220 instead of 110 (it had a switch). I inverse the oil and filter, and replaced the air filter, showtime thing (with genuine Komatsu parts lol). I take a new fuel filter element and will replace that as well. It certainly is possible that there is an issue with the fuel system that causes bereft fuel to exist delivered, stalling the engine. But why would that exist temperature related if it was, due east.g., a fuel filter trouble? When the engine stalls, it feels like it is lugging, like the load is also high. No sputtering, smoking, cough, or anything like that. It just slows downwardly rapidly and stalls. I would estimate that information technology takes maybe half a 2nd to become from 2,500 RPM (approx) to stalled. Information technology does that if you agree whatever hydraulic control to the full in or out position. If you lot hold the control for a fraction of a second, the engine starts to lug (RPM'due south falls). If you then release the hydraulic command, the engine returns to normal RPM. You tin can do that over and over. And over again, it just happens when the auto is warm. When it is cold, y'all can concur the control at full all y'all desire and nothing bad happens. John C. Senior Member Joined: Jun 12, 2007 Messages: 10,947 Occupation: Mechanism & Equipment Appraiser Location: Northwest Are you lot saying that you have a service manual for the machine? Yep, I have both the Shop Manual and the Operations and Maintenance Manual. In that location is a diagnostic procedure in the Store Manual for "engine speed lowers extremely or engine stalls" - that is where I started (and why I measured the main relief pressure as my first step). Delmer Senior Member Joined: January 4, 2013 Messages: vii,394 Location: WI You could say the manual is designed for the dealer diagnosing new machines, and they will have more likely issues subsequently 3,000 hrs. If a hose was cracked and sucking air, that would usually get worse equally information technology got hotter. I'd like to see at to the lowest degree a niggling visible or dark smoke to indicate the engine was getting enough fuel. John C. Senior Member Joined: Jun 12, 2007 Messages: ten,947 Occupation: Machinery & Equipment Appraiser Location: Northwest I was going to send you the manual simply since you lot already have ane I think would be a waste matter. Maybe if I explain how the system is supposed to piece of work it might help. Information technology is a closed center load sensing blazon of organization. The nuts are that the pump supply a footling more than oil to the functions than is necessary. Trying to go far uncomplicated here, if the amount of oil you need is twenty gallons a minute, the pump will put out 23 gallons a infinitesimal. It is done by monitoring pressures. Output pressure of the pump is sensed on the torque variable control valve which also senses pressure on all the functions after menstruation leaves the primary command valve. That is normally called load sensing pressure. The standard difference or "delta" is around 300 PSI normally. Load sensing "delta" is difficult to actually mensurate and Komatsu uses a special approximate that can sense both pressure and read out the divergence or "delta." I usually do it with two gauges and note that they only testify approximates as I have to effigy the difference in my head. And then I suspect what is going on is that the TVC valve is reacting too much and keeping the pump on stroke which pulls more horse power than the engine tin can produce. Study your book and try to find something that references the TVC valve and shows you lot where information technology is at. It volition be on the pump somewhere only I haven't worked on this model of auto and then can't tell you lot where it is and what it looks like. Normally it will be a large lock nut on a slotted commodities on the side of the pump. Y'all will have to find out which way to turn it to back off the pump enough to quit killing the engine. Let u.s.a. know what you lot notice. Right! Very helpful. On this machine, that TVC valve is called the LS valve. They enquire you to measure the differential pressure using the special gauge that y'all mentioned. I tried to buy ane, just can't detect one for a reasonable price. And so I will do every bit you suggest, and measure with ii gauges then do the math. Now, here is the suspicious affair. The LS valve (or at to the lowest degree the ports that you measure the differential force per unit area from) are on the dorsum of the hydraulic pump about the muffler. My working theory is that the muffler, which is missing its heat shield, is overheating some component in the LS valve, which is causing it to (as you lot advise) fail to practice its task one time the automobile gets hot. I will mensurate the LS differential pressure while both cold (and thus working fine) and hot (and thus non working fine) and written report back. Thanks very much to anybody for their help and suggestions, I really appreciate information technology very much! I'd like to run across fuel force per unit area afterward the lift pump, both at full throttle unloaded and loaded. Certainly that will exist a lot easier to measure Turns out that there is neither a spec for fuel pressure in the Shop Manual, nor a process for measuring it... Anyone have a sense of what proper fuel pressure might exist? John C. Senior Fellow member Joined: Jun 12, 2007 Messages: 10,947 Occupation: Machinery & Equipment Appraiser Location: Northwest As I recall those accept an electric fuel pump and they work or they don't. The the line off at the fuel injection supply connection and come across if fuel comes out when you turn the key on. Ok, I have made some progress, only am definitely stumped. I tested the Main Relief Valve, and it appears to office ordinarily. I as well tested the LS valve (the differential pressure valve that controls the variable output pump), and it likewise appears to function normally. By "role normally" what I mean is that while the machine is "cold" I can measure the pressures and they are right by the volume. When the machine is not, I tin't measure the pressures because the engine dies when I effort to exercise and so, only they seem to exist trending unremarkably immediately earlier the engine dies. But more chiefly, while conducting these tests, I verified that the machine operates completely normally when "common cold", and that the engine quits predictably and reliably (and very quickly) if whatsoever hydraulic control is run to the limit while the machine is "hot". I demand to run more than detailed tests, maybe with a temperature measuring device installed, only it appears that "cold" = engine temp approximate on the peg (which I presume also means that the thermostat betwixt the block and the radiator is even so closed). "Hot" = whatever movement of the needle off the peg, which I am guessing correlates to the thermostat opening. The one other data point that I accept is that when I went to replace the air filter elements (mine has dual elements), I found an old thermostat sitting on the air filter housing. That suggests to me that someone else went downwardly this route - and perhaps replaced the thermostat (or took it out and left it out, I take not verified that there is 1 installed currently). I am now beginning to think that this must exist an engine problem, about likely a fuel problem, and not a hydraulic trouble. I simply can't figure out whatsoever reason for the hydraulic system to be effected past engine temperature. There is no hydraulic fluid cooler associated with the radiator. I did insulate the muffler, which is shut to the hydraulic pump, and that made no difference at all. Anyone have whatever thoughts about what to check in the fuel system, or how to plumb in a fuel pressure sensor? This automobile has a Komatsu 3D88E-5P Diesel engine. I suspect that there may be a shop or MX manual for the engine that is separate from the volume for the automobile, I am going to go wait and see if I can discover it. Maybe information technology will shed some light on the fuel system. Delmer Senior Member Joined: Jan 4, 2013 Messages: seven,394 Location: WI what kind of hoses and fittings are the fuel supply to the injection pump? get a tee and run a line to the cab with a pressure level/vacuum gauge and so you lot can see what the pressure is at idle, high idle, and under load common cold, , then hot. The specific fuel pressure level isn't so critical to me, more looking for it to stay somewhat steady. If information technology drops off with engine load more when hot, then you lot take something to check further. How about some pictures of the fuel filters, lines, and injection pump? There's a few components that LOVE to fail, that are easy to ID from pictures, but I'd be guessing what you take without a picture. I will take some pics tomorrow and mail service them. Turns out this machine has iii fuel pumps. Perhaps anybody knew that except me lol. An electric pump to get fuel out of the tank. It is positioned between the h2o separator and fuel filter behind the engine, and is very easily accessible. An intermediate pump that they call the trochoid pump (built in to the main injection pump) that raises the pressure to the required input force per unit area for the injection pump, and and then the main engine driven injection pump. Delmer Senior Member Joined: Jan iv, 2013 Messages: vii,394 Location: WI I forgot to mention (once more) sucking air, yous could run the render into a department of clear tubing, or into a glass jar to run across if there's any air bubbling when it stalls. Forums Forums Members Members Menu Share this post
I recently bought a used PC35 with about 3,000 hours on information technology. I knew that it had this issue when I bought it, and I got an appropriate discount, only at present information technology is time to diagnose and repair. I am very handy, but take zero experience with this kind of hydraulic equipment. The car works fine when it is cold. Just once it warms up, ie once the temp approximate rises off the peg to a normal operating temperature (I have not measured the exact temp at which this happens, and I don't know if it is engine temp or hydraulic fluid temp that matters), the engine will stall if whatsoever hydraulic role is run to the limit and held there even briefly. ie, when cold, the chief relief valve and related relief components seem to work fine, just when hot, something doesn't work right and the engine stalls. I checked the idle and total throttle RPM, and they are to spec. The first diagnostic footstep in the shop manual is to check the Master Relief Valve, so as suggested I measured the relief pressure when this happens, and the pressure rises to about 24 Mpa just before the engine stalls. Main relief force per unit area spec is 26. So that seems ok - I presume that the failure style is when the relief pressure is too loftier. My next move, based on the store manual diagnostic flow for "Engine stalls", was to measure the differential LS pressure. When I started to look into doing that, I discovered a bunch of aluminum foil stuffed between the muffler and the master hydraulic pump. That led me to dorsum to the shop manual, which shows (in pics) the muffler covered in some kind of insulation. That insulation is missing from my muffler. And office of the principal hydraulic pump that contains the LS parts is closest to the muffler. Has anyone seen anything like this? Does the heat shield/insulation on the muffler seem important, of import enough to cause part of the hydraulic pump to overheat if information technology is missing? Any hints, suggestions or guidance - esp of the form, "Oh aye, every PC35 that I have ever seen has this issue when..." would be near appreciated.
You might consider giving a series number so we take and idea of which Dash series auto y'all have. I've never had to spend whatever fourth dimension working on the Komatsu minis so possibly someone volition come along with better insights. As fas as the heat shield for the muffler goes,it is kind of important as the estrus will bake the insulation on the wires going to whatever electric components. The heating problems usually started with the coolers and radiators which were non piece of cake to clean on standard machines and is fabricated exponentially worse on mine exes. Everything is tight and the counterweight many times has to be removed for access just to blow the dust out of the fins. Every bit far as the hydraulics stopping the engine go, that shouldn't happen at all. As I think, virtually of those machines had a unmarried piston pump and a gear pump on the dorsum that ran the blade and peradventure the swing but I'thou not certain of that. I call up I have a manual somewhere only won't know if it applies to your automobile unless yous post a serial number. Does the cab on your machine tilt for admission to the control valve?
Cheers for the reply John. Series # is 09865. Auto is a PC35MR-ii . Canopy, no cab.This machine appears to accept a single pump, with a single piston, but information technology has two output ports. I exercise not believe that there is a 2d, separate, hydraulic pump. The trouble occurs when any hydraulic function, including travel, is used to the limit. The cab does tilt for admission to the control valve.
I've never seen a PC35 then I'll leave that to John C, he seems to be the best answer you lot're going to get on some of those. You might be barking up the wrong tree looking at the hydraulics first. This isn't a large excavator with a more complicated hydraulic system with lots to go wrong, and lots of "optimization". This volition be relatively crude and simple. How nearly the fuel organisation? What does the engine practise when it stalls? sputter? dark smoke? no smoke? will it recover right away if you allow off soon plenty? or does information technology seem like information technology merely switches off? I don't know that fuel system either, merely I'd be looking for a croaky condom fuel suction hose, or a plugged banjo bolt screen.
My source shows your auto to be an MR1 simply information technology may be wrong which would mean you take a gray market place car. My source says there were no MR2 machines sold for domestic employ in the U.s.a.. I"ll meet what I have for reference material and get back to you.
The data plate and placards are in English language, which is no guarantee but suggests that the original destination market was the US. Also, I know this machine was owned by a local municipal authorities originally, which again argues against grey market. I can mail service a picture of the information plate if that would be useful.
All information plates for Komatsu that I have seen in the past dozen years have been in English. PM me your email address and I can ship you a link with some information. The motorcar does have a single piston pump that has the ability to act like a double pump and it does have a gear pump mounted on the back of the piston pump. At that place were MR-ii machines sold here. It is possible someone messed with the controls on the pump or that there may a problem in the main control valve LS circuits. Expect for broken paint on lock basics for the pump and valve controls for clues apropos tampering.
My first instinct was fuel or air too! But the shop transmission wants me to diagnose the hydraulics beginning, and my gut says that that is consistent with the actual behavior of the machine. That said, I had a generator with too much oil in the crankcase, and it would die in just this same way if you asked it to produce 220 instead of 110 (it had a switch). I inverse the oil and filter, and replaced the air filter, showtime thing (with genuine Komatsu parts lol). I take a new fuel filter element and will replace that as well. It certainly is possible that there is an issue with the fuel system that causes bereft fuel to exist delivered, stalling the engine. But why would that exist temperature related if it was, due east.g., a fuel filter trouble? When the engine stalls, it feels like it is lugging, like the load is also high. No sputtering, smoking, cough, or anything like that. It just slows downwardly rapidly and stalls. I would estimate that information technology takes maybe half a 2nd to become from 2,500 RPM (approx) to stalled. Information technology does that if you agree whatever hydraulic control to the full in or out position. If you lot hold the control for a fraction of a second, the engine starts to lug (RPM'due south falls). If you then release the hydraulic command, the engine returns to normal RPM. You tin can do that over and over. And over again, it just happens when the auto is warm. When it is cold, y'all can concur the control at full all y'all desire and nothing bad happens.
Yep, I have both the Shop Manual and the Operations and Maintenance Manual. In that location is a diagnostic procedure in the Store Manual for "engine speed lowers extremely or engine stalls" - that is where I started (and why I measured the main relief pressure as my first step).
You could say the manual is designed for the dealer diagnosing new machines, and they will have more likely issues subsequently 3,000 hrs. If a hose was cracked and sucking air, that would usually get worse equally information technology got hotter. I'd like to see at to the lowest degree a niggling visible or dark smoke to indicate the engine was getting enough fuel.
I was going to send you the manual simply since you lot already have ane I think would be a waste matter. Maybe if I explain how the system is supposed to piece of work it might help. Information technology is a closed center load sensing blazon of organization. The nuts are that the pump supply a footling more than oil to the functions than is necessary. Trying to go far uncomplicated here, if the amount of oil you need is twenty gallons a minute, the pump will put out 23 gallons a infinitesimal. It is done by monitoring pressures. Output pressure of the pump is sensed on the torque variable control valve which also senses pressure on all the functions after menstruation leaves the primary command valve. That is normally called load sensing pressure. The standard difference or "delta" is around 300 PSI normally. Load sensing "delta" is difficult to actually mensurate and Komatsu uses a special approximate that can sense both pressure and read out the divergence or "delta." I usually do it with two gauges and note that they only testify approximates as I have to effigy the difference in my head. And then I suspect what is going on is that the TVC valve is reacting too much and keeping the pump on stroke which pulls more horse power than the engine tin can produce. Study your book and try to find something that references the TVC valve and shows you lot where information technology is at. It volition be on the pump somewhere only I haven't worked on this model of auto and then can't tell you lot where it is and what it looks like. Normally it will be a large lock nut on a slotted commodities on the side of the pump. Y'all will have to find out which way to turn it to back off the pump enough to quit killing the engine. Let u.s.a. know what you lot notice.
Right! Very helpful. On this machine, that TVC valve is called the LS valve. They enquire you to measure the differential pressure using the special gauge that y'all mentioned. I tried to buy ane, just can't detect one for a reasonable price. And so I will do every bit you suggest, and measure with ii gauges then do the math. Now, here is the suspicious affair. The LS valve (or at to the lowest degree the ports that you measure the differential force per unit area from) are on the dorsum of the hydraulic pump about the muffler. My working theory is that the muffler, which is missing its heat shield, is overheating some component in the LS valve, which is causing it to (as you lot advise) fail to practice its task one time the automobile gets hot. I will mensurate the LS differential pressure while both cold (and thus working fine) and hot (and thus non working fine) and written report back. Thanks very much to anybody for their help and suggestions, I really appreciate information technology very much!
I'd like to run across fuel force per unit area afterward the lift pump, both at full throttle unloaded and loaded. Certainly that will exist a lot easier to measure
Turns out that there is neither a spec for fuel pressure in the Shop Manual, nor a process for measuring it... Anyone have a sense of what proper fuel pressure might exist?
As I recall those accept an electric fuel pump and they work or they don't. The the line off at the fuel injection supply connection and come across if fuel comes out when you turn the key on.
Ok, I have made some progress, only am definitely stumped. I tested the Main Relief Valve, and it appears to office ordinarily. I as well tested the LS valve (the differential pressure valve that controls the variable output pump), and it likewise appears to function normally. By "role normally" what I mean is that while the machine is "cold" I can measure the pressures and they are right by the volume. When the machine is not, I tin't measure the pressures because the engine dies when I effort to exercise and so, only they seem to exist trending unremarkably immediately earlier the engine dies. But more chiefly, while conducting these tests, I verified that the machine operates completely normally when "common cold", and that the engine quits predictably and reliably (and very quickly) if whatsoever hydraulic control is run to the limit while the machine is "hot". I demand to run more than detailed tests, maybe with a temperature measuring device installed, only it appears that "cold" = engine temp approximate on the peg (which I presume also means that the thermostat betwixt the block and the radiator is even so closed). "Hot" = whatever movement of the needle off the peg, which I am guessing correlates to the thermostat opening. The one other data point that I accept is that when I went to replace the air filter elements (mine has dual elements), I found an old thermostat sitting on the air filter housing. That suggests to me that someone else went downwardly this route - and perhaps replaced the thermostat (or took it out and left it out, I take not verified that there is 1 installed currently). I am now beginning to think that this must exist an engine problem, about likely a fuel problem, and not a hydraulic trouble. I simply can't figure out whatsoever reason for the hydraulic system to be effected past engine temperature. There is no hydraulic fluid cooler associated with the radiator. I did insulate the muffler, which is shut to the hydraulic pump, and that made no difference at all. Anyone have whatever thoughts about what to check in the fuel system, or how to plumb in a fuel pressure sensor? This automobile has a Komatsu 3D88E-5P Diesel engine. I suspect that there may be a shop or MX manual for the engine that is separate from the volume for the automobile, I am going to go wait and see if I can discover it. Maybe information technology will shed some light on the fuel system.
what kind of hoses and fittings are the fuel supply to the injection pump? get a tee and run a line to the cab with a pressure level/vacuum gauge and so you lot can see what the pressure is at idle, high idle, and under load common cold, , then hot. The specific fuel pressure level isn't so critical to me, more looking for it to stay somewhat steady. If information technology drops off with engine load more when hot, then you lot take something to check further. How about some pictures of the fuel filters, lines, and injection pump? There's a few components that LOVE to fail, that are easy to ID from pictures, but I'd be guessing what you take without a picture.
I will take some pics tomorrow and mail service them. Turns out this machine has iii fuel pumps. Perhaps anybody knew that except me lol. An electric pump to get fuel out of the tank. It is positioned between the h2o separator and fuel filter behind the engine, and is very easily accessible. An intermediate pump that they call the trochoid pump (built in to the main injection pump) that raises the pressure to the required input force per unit area for the injection pump, and and then the main engine driven injection pump.
I forgot to mention (once more) sucking air, yous could run the render into a department of clear tubing, or into a glass jar to run across if there's any air bubbling when it stalls.
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