ok i had a brake seal go bad recently i had pulled the left side drive motor and had it completly overhauled new berings new seals everything. well here is my problem i put it all back together and didnt know there was a procedure to it and started it up, and now it has power to the right side wheels and the boom and the brake relese just nothign to the drive motor itself liek the pump had drained out and cavitated. i cracked lines to try and bleed air out and i have drained filter and even tried to presurize the system but for soem reason the charge pump is pumping fluid trough it and it snot buildign pressure. i am gettign pressure fromthe charge pump to the lines btu the valve body doesnt even while like its not gettign any fluid . and it doesnt change the pressure when i move the joystick either. i have been workign on this for almost 3 days straight can soemone please give me some sort of insight here please.
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frogfarmer
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No real experience with that machine but 60psi is low for a lot of machines on the charge pressure. What does a Deere service manual give for the charge pressure specs. A service manual is money well spent on an expensive piece of equipment. Everything else aside we are assuming the motor rebuild was done correctly. And we all know what assumptions do.
well the pecs say from 60-100psi for the charge pump in the manual, the pressure doesnt change when the steering stick is moved it sjust the constant charge pressure. i am abotu at my witts end i am ready to draint he entire system and start over.
does anyone know if ther eneeds to be resistance to build pressure in this system ???
i ave read the manual from cover to cover and my 250 doe4s not have the geroler drive moptor it has a sauer danfoss 400 series pump and i cant find much tecnical info on it , and i dont know what to think. because from what i understand the front pump controls the bucket and boom and the left wheels but the right pump controle right wheels but i amso lost and just cant seem to completly understad shy it fdoes not work. if i can rebuild a detroit 453 diesel i shoudl be able to figure out why thie damned thign doesnt work.
frogfarmer
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Sounds like frustration has set in pretty good; been there done that. As I stated before no real experience with that unit. The brake releases are hydraulic and the brakes run in oil. If the brakes were installed dry and the surrounding area is full of air it may be very difficult to bleed due to the fact that it takes very little fluid to actuate the brakes. I have seen this senerio before but it wasn't a Deere and memory fails me as to what it actually was. How much have you run the unit since the repair? Does it have any unusual noises. The charge pressure is to feed the hydro pumps so they are most likely getting what they need. The hydro pumps feed the drive motors in an almost closed loop system.
frogfarmer
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Ok I checked the parts break down and here is what I saw. That unit has a pretty normal setup. Engine drives a tamdem Hydrostat pump (one for the left and one for the right all in one assembly) coupled to the tandem pump is the hydraulic pump that creates pressure for the lift and tilt on the boom. Your drive motors are geroler design with the brake section built into the housing. Geroler motors normally have no trouble purging air due to their design. I would suspect the brake section to have the system locked up. Does the engine change when the dead stick is stroked? I have seen geroler motors put together wrong and would turn backward due to the valving but I doubt if they would bypass completely. Did all the hoses and lines get put in the same port when reinstalled? Do the tires turn freely because the chains are off the sprockets?
ok first off its a danfoss tmt 400 drive motors/brake assembly, the stroke on the travel control has no load or anythign on the diesel motor, the hydrolics unlock fine, bucket and boom go up and down fine, the right side(sittignin the machine) drives fine and both wheels unlock the brakes fine. it just does not drive. i have used the search bar for machines that use the danfoss motors just tryign t9o find more ifo on the danfoss motors. i am 99% positive that the motor and brake were assemebeled corectly as i watched when the (retired cat mechanic) rebuilt and replaced seals and berings on the drive assembely, i also put new chains and sprockets on and newer used tires and really started puttign alot of money into this machine to make it ready, and i rely on my equipment to run my business and time is runnign out and i am just gettign frusterated with it .
frogfarmer
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I would let it run and build some heat and then take some temp readings with an IR temp sensor. If I had flow through the drive motor I would pull the motor and find the problem. If I had no flow through the drive motor I would crack the lines to the motor and see if any oil was present. If oil was present I would hook up guages to test pressure from the hydro pump. If no oil I would suspect no charge oil to the hydro pump and check charge pressure for that pump. I would be extremely surprised if I didn't find the problem with this approach. Anything is possible but introduction of foreign material into the hydro system may have caused a failure. System may only be air locked and needs a line here and there opened.
ok well here is what i had found out, i have charge pressure trough both pumps, and it ran perfectly fine before the teardown of the drive motor, it as just a brake seal that went bad. but the pump sat dry for a few months while tryign to order parts. and i have tried cracking line after line and figureign out withc way the fluid flows and the direction of it all, i have even let it sit and just a bpbve idle for 30 min or so hoping to work out some of the air in the system. i have charge pressure to the motors but ther eis no change in the pressure when the travel stick is moved? but from the way the hoses are doesnt the front pump supply the bucket controls also? i mean i know it has a little moisture int he system but i am so overwhelmed and dont know where to turn. this is nowhere near as complicated as my excavator and its got to be soemthign simple i am overlooking. i have looked to try and locate a spool valve and i have searched for a diagram or schematic of the tmt 400 style drive motor and have not had much luck, theseries number is 151z3225 but i cant find that exact one anywhere.
i have also run about 15 galons of oil trough the lines trying to purge air from the system also. i dont have acess toguages to get pressur ereading i do knwo the charge pump is pushing a little over 60 psi but what it seems liek its buildign pressur ebut its not lettign pressure go to the manifold and to the drive motors like it should.
frogfarmer
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Its not unusual for it to be difficult to cross the specific number on the motor because the end use was for Deere. The 400 series motors are common and come in several varieties. The Deere site has a complete parts breakdown online that shows everything on the unit. You state the system was open for months. Were the hoses all covered to keep out bugs and other critters. I have removed parts of mice and frogs from systems not to mention all the times I have found dirt packed in the lines from flying insects. I learned a long time ago to plug any open line. You also stated the motors had charge pressure did you mean the hydro pumps had charge pressure. I don't remember the exact specs but it seems like it takes 250psi to release the brakes fully and there is an orifice that restricts flow to a tenth of a gallon a minute on the brakes. If something crawled up a line and got chewed up you may need to remove the pumps and inspect for damage.
frogfarmer
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Does the stick actually move the swash plate in the pump. Bellcranks can come loose and during the motor fix maybe something was moved out of the ordinary. Everything may be fine and the linkage is inop. Just a thought
it really does seem liek its not doign anythign but moving the linkage and i dont thign the swash plate is moving, and alotther thign is i think there mat have been soemthign in the hyd resivor also , i was usign coffee filters and had one come apart to strain the hyd fluid for reuse. i am just going over the common things, where woudl you guys start? train the resivor and pull all the hoses drain the lines completly and try and make sure ther eis nothgin obstructign them?? and where exactly would it be obstructed in the resivor in the charge pump in the fronyt or back pump or the motors? any info on where to start woudl be greatly appreciated
If a coffee filter fell apart it wouldn't prevent it pumping oil all together. I hope you got all the paper out as its the first thing they tell you not to use when assembling any hydraulic item. Use air, not paper as particles can get stuck and cause wear. Hydraulic components are very tight tollerance, anything that gets stuck can quickly score moving parts, especially rotating groups in the drive pumps.
well i know somethign i never knew before. and if the pump was going bad wouldnt it still make some pressure and spin the wheels with them off the ground and no resistance on them?? i am not gettign anything and whine or anything from the pump.
frogfarmer
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Given you know some debris was introduced to the system reservoir I would be looking at the low pressure fluid feed to the problem pump. Commonly called the charge line. Blockage could be in a T fitting that sends fluid to both pumps. An IR point and shoot thermometer would tell you if you have a blockage due to heat change at the blockage. I worked on a brand new unit with no drive to one side it was set up to feed both pumps from the filter housing that was cast aluminum. The feed to one pump was completely blocked with casting slag. Needless to say that housing was overnighted to the manufacturer and we sent the entire unit back. Tazza is right about the paper all the manufacturers specify a lint free enviroment. If you had no fluid in the problem pump due to a blockage at initial startup you may have scored the mating surfaces badly enough to ruin the pump. At some point the blockage may have passed but the damage was done. If you can verify the problem pump has charge fluid I would suspect it is bad; but I would check the motor lines with a guage to verify.
Even with wear, i'd suspect the pump would provide some pressure to the motor and spin it if the wheels were clear of the ground to rotate.
I have to agree with frogfarmer, check you are getting charge pressure, if so, you may need to pull the pump down and inspect it for damage. Its weird its not pumping, as you only got the drive motor done and didn't fiddle with the pump...