CAT 257 hydraulic tilt will not hold

[crwood078]

I have a CAT 257 model (not the 257B) and when tilting the bucket up, it slowly falls back down when releasing the joystick. The lift arm works fine, I can raise it up, let go of stick and it stays in that position but the tilt will not hold. I replaced the relief valve (Valve GP-Relief Part No.216-6160) at the hydraulic bank under cab but that did not fix the problem. I changed the valve that is the furthest to the left on the front of bank when looking toward rear of machine while sitting on the entry step to cab with cab raised. Is it possible I changed the wrong valve? From the diagram from CAT, it is the #2 reference number on "bottom view" of bank. Or is there a separate pump to control tilt function and could it be that pump if so? All other functions work, tracks & lift. Any help please!

 

[davesl708]

Hi. Welcome. Could it be the orings on the cylinder piston are worn and letting the fluid bypass causing it to fall back down?

 

[oldnslo]

I agree with Dave it sounds like leaking tilt cylinders.

A quick test If you can easily access the lines that go to the rod ends of the tilt cylinders and have access to some caps and plugs for the hose ends. Note: I believe Cat uses ORFS (O-Ring Face Seal) fittings

Lower the bucket fully shut the engine off and release all of the pressure in the lines. Remove the lines from the rod end of the tilt cylinders and cap them off.

Start the skid loader up and raise the bucket of the ground. Do the tilt cylinders drift out and allow the bucket to dump. If yes the seals are bad in the cylinders.

 

[crwood078]

I agree with Dave it sounds like leaking tilt cylinders.

A quick test If you can easily access the lines that go to the rod ends of the tilt cylinders and have access to some caps and plugs for the hose ends. Note: I believe Cat uses ORFS (O-Ring Face Seal) fittings

Lower the bucket fully shut the engine off and release all of the pressure in the lines. Remove the lines from the rod end of the tilt cylinders and cap them off.

Start the skid loader up and raise the bucket of the ground. Do the tilt cylinders drift out and allow the bucket to dump. If yes the seals are bad in the cylinders.

Hey and thanks for the replies oldnslo & Dave, I'm actually at the CAT store here in Birmingham now and it's as if you repeated exactly what one of the mechanics here said to try doing, with the exception of what to do about a leaking cylinder; it sounded like the mechanic was implying it would require a new cylinder or to rebuild the cylinder as opposed to your thoughts of just replacing the seals. The parts Dept was trying to find the plug & caps that fit onto the lines but didn't have them at this location (rental store in bham) but said they should have them at the main Caterpillar store in Tarrant which is 10 min away. Thanks a bunch for your advice and I will update you on the status.

 

[oldnslo]

rebuilding a cylinder can be just replacing the seals or if the cylinder rod is damaged replacing the rod etc.

Good luck

 

[crwood078]

rebuilding a cylinder can be just replacing the seals or if the cylinder rod is damaged replacing the rod etc.

Good luck

Ok, do you know where I might find some instructional information on how to go about doing that, replacing the seals? That is if that repair is something a non-pro mechanic like myself could attempt to do. I've never worked on a hydraulic cylinder before; I have: replaced bogie wheels, replaced tracks, changed starter and replaced the exhaust elbow pipe (between exhaust manifold & muffler) on this machine but never messed with a hydraulic cylinder. As far as damage to the rod, what kind of damage would I be looking for, like some obvious & apparent gouges in the metal surface of rod? (If I'm visualizing how the hydraulics work, if there were gouges to the metal surface of rod, that would allow hydraulic fluid to flow/leak past the seals?) And forgive me for this stupid question but, is the rod the smooth shiny part of the hydraulic cylinder?

 

[oldnslo]

No forgiveness required we learn by asking questions and or doing sometimes foolish things.

Cylinder components:
1) Cylinder rod: is the shining shaft that slides in and out of the cylinder.
2) Rod end cap: On most Ag & construction equipment this is threaded into the cylinder barrel or housing. Sometimes there is also a retaining ring holding this in place.
3) Piston: This is attached to the cylinder rod inside of the cylinder barrel or housing.
4) Cylinder housing: This is the outer body of the cylinder. The inside is honed for the piston seals to ride on.

Disassembly: Does Cat have a parts breakdown available. I would hate to guess wrong on your cylinder is made and have you screw something up.

 

[crwood078]

Well Roy, I finally disconnected the hydraulic lines going to the tilt cylinder, capped & plugged the ends and started the machine up & raised the bucket in the air...and the bucket held its position. I raised the lift arm to put the bucket about 3' off the ground & let go of the controls, let it sit for a good 30-60 seconds and the bucket did not limp down. So I guess that means the cylinder is good, any idea what else it could be? Again, I already changed the relief valve at the hydraulic bank under the cab & unless I changed the wrong valve, that didn't fix the problem. Thanks again for your help so far.

 

[Ryan LaFata]

Hi crwood078, I just read through your thread here and I have the same problem with my cat 257 track loader. I wanted to know if you ever figured out what the solution was to the hydraulic tilt not holding? I have aready Checked the tilt Pistons and they are all good. If you could respond back with what your solution was I would greatly apreciate it.

Thanks,

 

[Moe's Grading]

I need help with removing the tilt cylinder on my 257B skid steer the seals are leaking I have the bottom pin off but don't know how to remove the top one. Any help is greatly appreciated.