Anybody have experience with these?
The company I work for has a Bobcat 331 mini excavator, and that thing is driving me nuts. Bobcat's tech support is abysmal, and their manuals don't have an effective diagnostic tree or troubleshooting procedure.
The problem is, there are a couple of functions that don't work properly. The left track, swing, front blade, and the auxillary hydraulics all work with minimal speed and no power. Usually, the machine can pick itself up with the blade, and this one can't even pick the blade off the ground. Also, forget turning right with the left track. I called Bobcat, they said to check all the pressure relief valves, I did that yesterday and they are all fine. Has anybody here had to deal with this sort of problem?

 

does it stall under load?

 

Nope. When using the swing, left track, blade, or aux. hydraulics, there isn't any load on the motor, no change in rpm anyways.

 

is there air in the system? low hydrostatic fluid? or the pump or valves are worn out. bobcat has the WORST customer service.

 

follow the flow of the fluid, have you checked for blockages, collaped hoses? just tossing out some ideas.

 

imo

To be fair to Bobcat, the idea behind Bobcat and other heavy equipment is you are suppose to take it to the local selling dealer where you bought it new if you can not fix it yourself. That is why they have a dealer network. They have no interest in supporting new or used equipment after warranty as it passes through dozens of hands in its 40+ year life span or to give everyone an education in hydraulics who wants to drive it or fix it.

Businesses (as an example) such as Perimeter Bobcat in Atlanta are many times a family run business that has been supporting Bobcat customers for decades. That is where the support is, not a telephone line. Would you try calling Ford with an OBDII code to help solve a no power problem and expect the person answering the phone to be a master technician, if you could even reach anyone?

> their manuals don't have an effective diagnostic tree or troubleshooting procedure.

Because relatively speaking, it is pretty simple.

Most equipment when overloaded will blow the pressure relief valve before the cyl. or ram bursts or a hard part breaks. Depending on the equipment, once activated it either automatically resets (by pass) or requires replacement.

With my limited experience of hydraulics I guess I have to ask how did you determine the pressure relief valve is working properly? Did you put a 5K gauge before and after the valves to determine if pressure is being exceeded in use or if the valve is actually stuck open?

After I checked for obvious leaks, how I would solve the problem

<insert grain of salt here> $0.02

Build a manifold (octopus) with a set of four pressure guages ( 8 hoses). Hook it up and have it long enough so it can be seen from the operators station. Between Northern Tools and the NAPA Hydraulic catalog (pre built hoses) it will be inexpensive to build and will be a great test tool. Just remember to wear safety goggles and avoid skin injection. It is not much of a barrier, but, I would wear leather gloves with the Kevlar lining.

I think 5K for all components would be enough, but, go by the machine specs and exceed the max. pressure expected. I would not leave the manifold to vibrate against the equipment or chance it being crushed. I would make a hanger for it with multiple (read bungie cords) flexible attachments or cushion it within a foam box if leaving it on the back of the machine behind the cage.

Myself, I would buy all the parts myself and keep it in my toolbox and would not loan it out. Besides making you more valuable I would not chance someone else messing it up by abuse and finding out when you get a missile of fluid in the head.