B100 hydraulic issues

[DANO4052]

Hello everyone,

My in-laws have a mid 90’s bobcat B100 loader backhoe that has been having some hydraulic issues. Whenever you actuate the loader bucket it slowly drops when the control is released, and when the backhoe is moved side to side it doesn’t stop when the control is released it just continues to move in whatever direction it was moving with no resistance. What should we be looking at to fix this?

Thanks!
Dan

 

[oldnslo]

Have the cylinders ever been rebuilt - resealed. Leaking seals will allow cylinders to drift.

 

[duffer]

No expert here, but it sounds like a control valve issue to me. Might have an internal O ring or seal gone bad.
Or it could be a loose connection on one of your hoses on the backhoe. Check all the connections for leaks first, and if that doesn't turn up anything, see if you can find a hydraulic mechanic who could look at the control valve for you.

If it's a bad control valve, you can sometimes find a new one cheaper than rebuilding one, depending on the type and brand of the control valve.
Here's where I got a replacement for mine:

Hydraulic Valves | Hydraulics | www.surpluscenter.com

Hydraulic Valves,Directional Control Valves,Log Splitter Valves,Joystick Valves,Solenoid Valves,Sectional Control Valves,Pilot Operated,Power Steering

www.surpluscenter.com

 

[oldnslo]

99% of control valves are metal to metal sealing with no rubber seals except to keep return oil from weeping around ends of spools onto the ground. If they are not spring centering properly they can allow cylinders to drift.

 

[DANO4052]

Thanks everyone for the suggestions. As far as I know none of the cylinders have ever been resealed, I have the service and repair manual now so I think I’ll follow the cylinder check procedure in the manual and see what happens.

I’m thinking maybe the bucket Falling is a cylinder leak, but the swing cylinder drift and the arm cylinder having jerky motion may be more control valve related? Not optimistic about the availability of the control valves if one or more is bad, would sealing issues between valves be a possible cause?

I would assume there would be visible leaks from the backhoe control valve area if the o-rings between the valve sections were bad. Anyway, as a first step the cylinder check procedure seems easy enough to do we may check all of them and reseal as required, providing we can get the proper seal kits and see how it acts after that.

 

[oldnslo]

The only place there could be seals on the directional valve that allow cylinder movement would be work port relief valves if your valve assembly has them. Majority of cylinder drift problems are bad seals in the cylinders.