Hello folks, I am new to this forum. I have a 95 CAT 320L with just under 10000 hours. When putting the machine in reverse the on track right hand side moves extremely slow almost sounds like a hissing noise. no fluid leaking all other functions work fine.
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CAT EXCAVATOR HYDROULIC ISSUE
- Thread starter cat 302
- Start date
uffex
Senior Member
Good day
If it is in one direction on one side it is probable that you have a issue with the shock valve.
Kind regards
Uffex
If it is in one direction on one side it is probable that you have a issue with the shock valve.
Kind regards
Uffex
If possible reverse the main hoses at the motor, or at the swivel under the machine, if the problem is then with forward movement instead of reverse (the control for that motor will be reversed in the cab) then it may be a blown out seal in the swivel joint/rotary manifold.
Nige
Senior Member
A Serial Number would help to locate accurate technical information. Lots of different 320s out there.
uffex
Senior Member
Good day
The port reliefs or shock valves for most crawler circuits are located at the motor easy to switch make sure you have unloaded the residual pressure before you attempt the switch the lines will be open to tank.
Kind regards
Uffex
The port reliefs or shock valves for most crawler circuits are located at the motor easy to switch make sure you have unloaded the residual pressure before you attempt the switch the lines will be open to tank.
Kind regards
Uffex
True that, and I never put a period after anything with machines, but I can't think of a failure in a hydraulic motor that only occurs in one direction. Still as you say, check the easy stuff first!
Thanks for all the replies 9kk00748 is the number off the machine. had a bit of a dump of snow so tomorrow I plan on investigating a bit more. when I am running it in reverse it sounds like when you only move a hydraulic function a little and it is makes a hissing noise. It is like a valve or something is not opening all the way or is jammed. the machine had many leaks before and I have slowly sealed them all up. It does sound like the hissing sound is coming from under the machine.
Nige
Senior Member
In the valve block right on the back of the travel motor (arrowed). it's Ref #3 on the cutaway illustration and there are two of them. Not sure which valve is for which direction but I suggest that you pull them both out and inspect. Maybe even try swapping them and see if the problem moves from the reverse direction to the forward direction.
Nige
Senior Member
Just a thought, when you pull the valves out have a good look at the condition of the O-Rings marked 1, 2, 10, & 11 on the detail drawing.
BigWrench55
Senior Member
Have you checked your pilot pressure to the spool? It could simply be the control valve dumping to tank from the way you described the symptom and sounds. I am just lurking so don't let me get you off track. I just like checking the simple things first. And so often we tend to go straight to the worst case scenario.
Good point!
I am too, when having problem with only some functions, first checking the controls instead of function actuator. Unless actuator fault is obvious.
I have not yet. I dont have that tool at this time however it sounds this could be a good investment. The machine is a 95 so I assume seals and different things will slowly need replacing. i have worked with this for a bit however it is just to frustrating at this point. its the only fuction and direction it does this on.
Well it looks like I am battling another problem at the moment I seem to keep loosing my Prime. It started a month ago would loose power a bit had to just let it idle for min would be fine then started happening more. I blew out the lines for the fuel tank, vacumed removed all bolts no screen found. new filter drained tank. bled started idles ok then you use power or work it it dies after about 2 min and it has gotten worse. I re prime it and it runs ok at idle but once I work it for 1 min it starts dying looses prime. I have now checked everything several times. It appears the fourth injector or line attached to the high pressure pump is weeping from what appears to be the top o ring or something. not much would this be the culprit?
BigWrench55
Senior Member
Are the filters sucking dry?