Cat 257 hydro problem

[DirtyWorks]

Ok guys my ol reliable 257 an 03 model with a lot of hours decided to lay down on me yesterday. There is no power to the lift or tilt. I can try to explain it better. It will lift and tilt when nothing is on the front, but put on my grapple @700-800lbs or even an empty dirt bucket @ 350lbs it will barely pick it up off the ground. I have to throttle all the way up and it will move up maby 2" and that is all. I let off the stick and do it again to get another few inches out of it. When no attachment it will lift fine. The machine moves/tracks as if no problem. I do not know if the aux hydraulics arefunctioning as I did not hook them up. I was worried that i may have a broken line but lfted the cab and found nothing obvious. I will not be able to get it to a dealer till tues or wed and would like to try to find the problem myself. Is it possible to be a relief bypassing or stuck? the machine does not bog or stall but does nothing if this info helps. I would like any and all advise. Thanks in advance.

 

[DirtyWorks]

Oh my guy was mowing with it when it did whatever it did. Could he have hit something ? The mower is/was supposed to have a sheer pin in it but I have since found out the soft bolt had been replaced by a much harder one than it should have. Is there a coupling in the machine that could have sheared instead and if so where would i find it?

 

[Terra Firma Scott]

Dirty, i had a hydro problem once with the L joystick...Unrelated to what you are experiencing (R joystick)but it was explained to me that fluid was bypassing in the valve assy related to that stick..mine would be driving forward and machine would start to make a very hard right turn and the reverse beacon would sound...Was told that the valve assy's related to the joysticks were a common fault especially w/higher hours.....might be something to look at ..think it was like 600 bux.

 

[Wayne County Hose]

Low pressure issues on multiple functions is usually a pump problem. I would follow the lines and see if there is a pump that controls these functions only. Pumps go bad many times before relief valves do. I've worked on hydraulics many years and don't know if I ever saw a relief valve go bad. I"m sure they do go bad, but I haven't seen it. I've seen plenty of pumps do just this. Do you have pressure gauges? I know that Cat's are pretty good with installing test ports.

 

[DirtyWorks]

Thanks Scott. I was hoping to find a pinched line or a bad leak or something obvious. I've never had a control problem, other than self inflicted, yet.

WC I do not have any gauges at this time but may welll need to invest in some. Never can have too many tools! I do believe there is only one pump on my machine that controls everything. Do the drive motors run directly off the pump and then the loader functions runn off a seperate piece? ie a coupler? Does my problem definately like a hydro related one vs an electrical one? ie fuse, safty, etc? I may have to wait till Tues if I do not come up with anything. Is there a way without knowing the exact pressures if some thing is stopped up or restricted? Thanks for the replies and I will keep yalll posted and up to date as I search for my solution. I may be the next person to look straight at the screen and declare..."I am NOT smarter than a CAT Technician"

 

[Robbie Hegwood]

Hey Dirt. I think WC has lead you very close to your problem. I think you were getting there on your own. If you had a leak bad enough to not lift you would hydro fluid everywhere. I would think if it was a fuse it wouldn't work at all. Sorry for the breakage!! It's hard to make money when your customer gives to you and you turn around and give it to the dealer!!

 

[diyDave]

Have you made sure that the switch is off that controls the attachment flow? Also is there a relief valve on the lifting cylinder that is sticking open? I know on my Asv Rc30, if you leave the continuous flow switch on, with nothing attached, it'll stall. Not too sure if yours is similar.

 

[DirtyWorks]

Dave, my asv is that way also. The little cat does not have a switch, just a momentary button like on your joystice. I do need to put a switch in though. The way it is now you thumb get tried quick!

 

[Terra Firma Scott]

hey dirty-I can lock my continuous flow so your thumb wheel finger can rest..I wonder if yours does also...My left joystick has 4 buttons on top and right has 2 buttons 1 wheel on top.

Right joystick-first,Roll the thumb wheel and hold

Left joystick-push and hold the bottom left botton -then let go of the thumb wheel and then the bottom left button...the attachment will run continuosly until one of the two forementoined butons or wheel is pushed again..

my finger used to get tired holding the wheel until i figured that out..Might be different on high flow model but try it...(once you get your lift/tilt figured out)

 

[DirtyWorks]

Scott mine is a lowflow older model with only two buttons on the right. Works great for opening and closing the shear or grapples but thats about it. Left has only a horn on top