hello long time lurker first time poster, i am writeing hopeing to get some advice on a hydraulic problem im haveing where the skidsteer is lossing drive power when the fluid heats up. a little history, i bought the machine not running and dead!!! theres not enough exclamation marks to indicate this but it comes with a good story. a deaf bloke was useing it and it developed a rod knock and becasue he was deaf he didnt hear it and as another person was running over to tell him becasue they could hear it acros the padock it died. 5 years later i became the new owner. ps the shel bearing had looked like it was put on an anvil and hit with a ball pein hammer and peend out under the rod and crank. i had rebuilt the motor, cylinders, new hoses, new paint, new wheel bearings and seal. rebuilt the bucket with hardox plate steel floor and back and turned it into a triple blade, new paint new new new. any way it got a major referbishment and after 6months of work im a little defated and need help with a problem thats a little out of my skill level. i can paint weld turn a spanner but other then a obvious hose burst i dont have much experiance with hydraulics. back to it lossing power it runs good when cold nice and snappy turns good on hard surface like concrete or rock drive way but it losses power evenly in both directions and turning and is makeing a chirping sound which i think is cavitation. i parked up yesterday and moved it today to where i can work on it good power but slight chirping. i have cut the old filter apart and nothing no debris dirt muck zero it looked really good. this is the filter it died with and was on the machine befor when it was being used. i did use iso68 fluid instead of the 10w30 and am wondering if this is my problem wrong fluid??? i am hopeing for a simple solution befor determining that the pump is worn out. i have a hydraulic mechanic comeing up tomorow from a close by town but want to try to eliminate a few things befor he gets here like a sticky return valve or the like, they charge alot $1.50per km + travel time at work shop fees of $140 itll be $300 to drive here and back befor hr turns a spanner. bit steep i know but i cant find any one else who is a real hydraulic mechanic and not a hose man with a pressure gauge. i have already looked up previous post and am writeing because i didnt find anything in them that helps me. hopefully some one has some insight
Why did you use such a thick oil if it calls for 10W-30?
availability of 10w30 hydraulic oil and on advice of a oils rep who supplies the local store that it is suitable for this application because it matches on viscosity index
If it works good until it's warm could be an oil issue. Does it work good again after it cools off for awhile?
hello yes it works good after its had a chance to cool down. i have bit the bullet and decided to pull the pump for a tear down.
hello to close of this thread i have rebuilt the pump but have an issue with the left hand drive at the moment and will be starting another thread regarding that. the pump was scored on the rotating group and brass plate
Your finding was what I expected as far as no power when warm, this is almost always caused by not cleaning the connections at the pumps and motors when replacing hoses, they must be absolutely clean, one grain of sand will destroy the brass commutator plate. Some style motors use the piston and commutator plate just like the pump but not all. It will be interesting to see what the motor looks like