Hey guys Im a new member and have a 99 jd 270 skid steer that is acting the same as the one that roadrunner81 had back in february this year and was wondering what the solution to the problem is. The problem is when you start the machine cold the boom lift and bucket curl are very slow but the boom powerdown and bucket dump work fine. However if you cycle the boom and bucket up and down 8 or 10 times it starts working like it should. Any ideas would help. Or if roadrunner81 could tell me what he found i would greatly appreciate it. Thanks.
Did this problem happen all the sudden? How are the drive controls right when you start it?
No this problem didnt happen over night but it has progressively gotten worse over the last year. 3 years ago i replaced the hydrostat pumps because the lovejoy coupler got loose on the pump shaft and slid back and ate the snap ring groove out of the rear pump $800 for an empty half housing so i put a new complete hydro in it for $2100 figuring the machine would last me as long as i would need it. I dont use more than 200 or 300 hours a year. Shortly after the hydro swap is when i noticed the boom lift seemed slower and when winter hit it really got bad. After talking to my local deere dealer they suggested changing the hydraulic fluid to low vis so i did, or thought i did i ran 15 gal of it thru the machine 5 gal at a time cycle everthing several times and drain it again. That was about this time last year and cant say that it helped much if any at all, but with cold wheather coming again i tried another 10 gal tonight problem is I wont be able to tell untill tomoro because once the machine warms up or the oil warms up it works fine. Now... to answer your question about the drive controls, they work fine at cold startup and i dont feel any loss of power when driving or pushing.
Just to clarify, you replaced the tandem pumps or the tandem and the gear pump? Strange as I believe the fluid from the res enters through the gear pump. It would be nice to swap them out quick (if you replaced it and had the old one). I think I would pressure test the hydros off the pump when its cold and check everywhere for leaks incase your getting air in the system and cycling it out. Just out of curiosity, when you changed pumps, what did you do to ensure the gear wouldn't crash into the pump again? When it ate the ring did it push fluid into the flywheel housing? Also, did you have any drive controls when the seal/ring went out?
yes tandems and gear pump complete unit from deere i put a spot of weld on the shaft on both sides of the lovejoy hub and locktite the set screws, the old pumps however igot tired of walking over and got rid of... not the best decision sure would come in handy right now say? When the seal got chewed out everything was still working fine I just started seeing oil puddles when i parked the machine so one day i went looking for the leak before it got worse. I dont like leaks.
I guess its hard to imagine a problem with the pump if the new one was from deere. If we rule that out; your left with the valve body. Check pressure before and after it (I would use the auxiliaries to check it after the control block). I am not sure how the lock-out solenoids work, could be related.
The lockouts are on the boom lift and bucket curl pressure side but i cant see how both lockouts on 2 seperate circuits would go bad at the same time let alone start working after oil warms up, so i dont think they would be to blame. Further more if it is a "thick oil problem" why does the boom power down and bucket dump work fine? I shouldnt say this but I used to work on these things for a living bout 11 years ago in Maryland, but Im finding that knowledge is alot like vacation time if you dont use it, you lose it! I dont have a pressure gauge to check with so Im hoping tomoro morning to see a difference with the new oil and a cold start up. If its still slow Im thinking pull the valve and check the spool travel mabey something on detent spring side aint right and not making full stroke.
Well changing the hyd oil didnt seem to help much it was around 28 degrees here today started up the machine and it still took a good 10 minutes of cycling the boom up and down while driving around before it started moving as it should so i started checking relief valves and lockout solenoids even pulled pressure line off from charge pump to valve and i cannot find anything that points to where the problem may be, no bad orings no metal flakes, no shiney stuff, no nothing. Im stumped. Starting to think cavitation issue but cant figure what or where to start.
Any updates on the issue?
Took control valve out replaced all seals put it back... didnt help. I dont know where else to look, the only thing left is the filter head witch supposedly has some kind of anti cavitation check in it that is non serviceable but for 600 bucks I hate to take another guess on that.