T 250 charge pressure

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Fishfiles

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On T 250's there is a gauge on the bottom left side the screen that is mounted on the right console , this bar gauge gives you the charge pressure which on this serial number and type is 390 to 430 psi at a fast idle , there is a bar under the gauge line that marks the minimum of the scale where the buzzer comes on and shutdown occurs after about 30 seconds ----the machine started with two problems at close to the same time which maybe be connected , first off it started shutting with a charge pressure extremely low warning , and I was told a couple of hours later it blew a travel motor and locked up the track on one side , changed the travel motor , the case drain rock filter and the hydraulic filter , cranked up and travel ok but machine still shutting down at idle or run , checked the drive belt and seemed a little loose so put a new belt , the results changed and they were that it would stay running at any rpm over 1600 but not below , the vital gauges menu on machine showed 157 psi at idle and 427 psi at full rpm's , about 230 psi at 1600rpm's and shut down anything less than 230 , so you have to keep it reved up to stay running , hooked in a manuel gauge into the system and found it right on with the machines readings so it is not a sending unit/sensor , wiring issue or controller /console problem , it's not a relief problem either as it gets to 430 and you can see the relief set in on the manuel gauge , I really think it's the charge pump , which is the other stage of the two stage gear pump mounted on the end of the sunstrand travel pump , here is the stumper , the charge pressure hose goes from the charge pump to a tee on the back side of the first section of the sunstrand then to the controll valve of the machine , so I am not totally asured that it is the charge pump causing the lost of pressure as I am not sure if pressure for the charging system can or can't be lost inside of the sunstrand or if the sunstrand is the problem itself ----I cut open the hydraulic filter and ran a magnet thru the element fins and it is full of ground up particles , the hydraulic filter was changed last in december and only had about 350 hours on it ---here is something I would like to know as I have never paid attention to it while on other 250's , I noticed that the charge pressure would drop dramaticly while traveling but stay pretty firm while using the bucket or boom , does any one with a 250/300 ever pay attention to what the charge pressure gauge is doing during operation of their machine ------- a manuel would sure help , may have to break down and buy one tomorrow
 

Fishfiles

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Well got a manuel for $60.00 , and learned alot , the charge pressure on a t250/300 can be lost in the sunstrand pump if the rotating group is worn , or if the brake of either travel motor is leaking internally , or from a bad charge pump , the relief is shim adjusted on the back side of the sunstrand pump which shouldn't be the problem as it reaches 430 psi ( the spec) running fast ------found no bronze colored particles inside the filter which make me think the rotating group is ok and by plugging the brake hoses and pressuring the brake found no increase of charge pressure at idle so no internal leaks there ---so it must be the $1,050.00 plus 9.75% tax charge pump , -------just trying to get myself to believe it but got a bad feeling on this one , as the local dealer told me they have one they are fighting right now with the same symptoms
 

Fishfiles

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Well got a manuel for $60.00 , and learned alot , the charge pressure on a t250/300 can be lost in the sunstrand pump if the rotating group is worn , or if the brake of either travel motor is leaking internally , or from a bad charge pump , the relief is shim adjusted on the back side of the sunstrand pump which shouldn't be the problem as it reaches 430 psi ( the spec) running fast ------found no bronze colored particles inside the filter which make me think the rotating group is ok and by plugging the brake hoses and pressuring the brake found no increase of charge pressure at idle so no internal leaks there ---so it must be the $1,050.00 plus 9.75% tax charge pump , -------just trying to get myself to believe it but got a bad feeling on this one , as the local dealer told me they have one they are fighting right now with the same symptoms
Well the charge pump fixed the problem for me , it cost $1,250 plus tax for the pump , $200 more than original quote as the first pump ordered was wrong , seems there is 3 different 250 configurations , glad it wasn't high flow as it is over $2,000 , wasn't really hard to change , a 2 hour job installing it
 

skidboy

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Jan 3, 2007
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Well the charge pump fixed the problem for me , it cost $1,250 plus tax for the pump , $200 more than original quote as the first pump ordered was wrong , seems there is 3 different 250 configurations , glad it wasn't high flow as it is over $2,000 , wasn't really hard to change , a 2 hour job installing it
Good to hear that the prob. is fixed. Was it all the crap that ruined the pump ? And how did you go about cleaning the system out ?
 

Fishfiles

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Good to hear that the prob. is fixed. Was it all the crap that ruined the pump ? And how did you go about cleaning the system out ?
I think the travel motor failure sent a load of metal into the sysytem , the bronze case drain rock filter was full to capacity and some must have got thru it , I disassembled the old charge pump and both sections of the pump were trashed , I see bad times for this machine in the furture as I am sure the metal went thru everything ,the pressure relief of the charge sysytem looked to be sandblasted by so much metal being forced thru it , I changed the hydraulic filter when I changed the travel motor and cut it open and it was full of powered metal , ran the machine for a couple days and changed the filter again when I changed the charge pump , it had a lot of trash but not nearly as much the second time , as far as cleaning out the system I don't know what could be down short of total disassembly , which I don't think would be practical , going to let it fly and hope the filters catches all the trash floating around , I am going to change the filter again in about a week cut it open and check it out ,
 

Tazza

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I think the travel motor failure sent a load of metal into the sysytem , the bronze case drain rock filter was full to capacity and some must have got thru it , I disassembled the old charge pump and both sections of the pump were trashed , I see bad times for this machine in the furture as I am sure the metal went thru everything ,the pressure relief of the charge sysytem looked to be sandblasted by so much metal being forced thru it , I changed the hydraulic filter when I changed the travel motor and cut it open and it was full of powered metal , ran the machine for a couple days and changed the filter again when I changed the charge pump , it had a lot of trash but not nearly as much the second time , as far as cleaning out the system I don't know what could be down short of total disassembly , which I don't think would be practical , going to let it fly and hope the filters catches all the trash floating around , I am going to change the filter again in about a week cut it open and check it out ,
Not the news you wanted to get.....
Larger particles are better than smaller ones though. If they are large, they will float around the system till they get caught by the filter. They aren't as bad as small ones that get between moving parts and start causing wear. I read somewhere that the smaller ones cause more problems because they get between the gaps between the pistons or swash plates and act like sand paper. The larger bits will not fit so they aren't as destructive, unless they get stuck in poppets or valves.
Drive motors that take a dump always send a lot of junk through the system. You really need to purge the system after replacing a motor that died like that. I spoke to a guy that does bobcats up and he was looking at buying one that the guy said he replaced a stuffed drive motor. He said did you change the oil? the guy said why? he just walked away.
Unfortunately i also see a world of pain down the track. Late model machines use pumps that use very close tolerance parts and any crap in the system can damage it. I'd be looking at moving it on if you can find another one to take its place. A new pump or motors will not be cheap!.
I hope its all ok though.
 

Fishfiles

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Feb 8, 2007
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1,698
Not the news you wanted to get.....
Larger particles are better than smaller ones though. If they are large, they will float around the system till they get caught by the filter. They aren't as bad as small ones that get between moving parts and start causing wear. I read somewhere that the smaller ones cause more problems because they get between the gaps between the pistons or swash plates and act like sand paper. The larger bits will not fit so they aren't as destructive, unless they get stuck in poppets or valves.
Drive motors that take a dump always send a lot of junk through the system. You really need to purge the system after replacing a motor that died like that. I spoke to a guy that does bobcats up and he was looking at buying one that the guy said he replaced a stuffed drive motor. He said did you change the oil? the guy said why? he just walked away.
Unfortunately i also see a world of pain down the track. Late model machines use pumps that use very close tolerance parts and any crap in the system can damage it. I'd be looking at moving it on if you can find another one to take its place. A new pump or motors will not be cheap!.
I hope its all ok though.
Expensive is an under statement , the T300 drive motor new goes for $4,300 plus the 9.75% tax, they are starting to have a few factory remaned units at $2,500 but the supply is limited , add the filters , oil and labor and your getting close to $6,000 per side ------some of the parts that I had removed like the reliefs looked as though they were sand blasted by all the metal that went through the system , the inside of the charge pump was heavily damaged and blued from metal passing thru it , that little rock filter that is in there doesn't seem to be big enough to catch all the debree assotiated with a major failure , changing the oil helps , but I am sure it is all over the system , have noticed on other machines when your rebuild a cylinder I see metal particles smashed into the piston packing , an indication that something went bad and stuff is floating around -------I think that when a person starts to hear or feel a problem in the tracking motor of T series loader they shold stop and have it checked out , when they run it to it doen't go any more they are in trouble -------I am think of working today ( saturday) which I try not to do , I have another T300 with a travel motor which is occasionally locking up , he has parked it and waiting on me , yesterday was a wash out as we got hammered by the rains all day , the unit has 1200 hours on it , right out the 1000 hour warranty , I asked if he had ever changed the planetary oil and he didn't even know about it , probally the cause of failure as it only holds 3 ounzes of Mobile synthetic 150 which over hear cost a whopping $40 for 6 ozs, thats $7 per oz , I had the oil matched up and the local oil suppler was happy to tell me he had it at $1,485 per 5 gallon can , thats about $3 per oz , it's the most expensive oil I have ever ran across
 
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