Hydraulic system causes the engine to stall after 30 mins of startup

[Scott Armst]

Please help. My komatsu tlb loses power and starts overheating soon after startup. When the hydraulic oil gets hot it starts straining the engine.if I operate any of the equipment the engine eases.Ihave just had a secondhand pump fited.could it be the pump causing this?

 

[J_J]

The pump is only going to work hard when there is resistance to the fluid. such as a cyl or motor doing work.

A relief valve going off will also heat up the fluid and overwork the fluid.

An open center hyd system is just pushing fluid through all the valves until you push a lever to redirect the fluid for work.

Install a hyd gage and when all the levers are in neutral, see if you have any pressure on the gage, and if so, you have a blockage.

Could also be a QD not connected correctly, or malfunctioning.

 

[Scott Armst]

when I first start up all operates fine. after 10 mins it starts hissing just below the back acter valves.the mechanic said he needs to put in another pump. It doesnot make sense to me. I am batling to identify where exactly the hiss is coming from as that could be the problem?

 

[bigdeano]

Your machine probably has a closed center pressure compensated system, a lot of the newer equipment does. The pump is supposed to stop pumping when a certain pressure is reached. If it keeps pumping it is probably blowing off a pressure relief which will cause a lot of heat and load the engine down.

 

[CJONE]

Your machine probably has a closed center pressure compensated system, a lot of the newer equipment does. The pump is supposed to stop pumping when a certain pressure is reached. If it keeps pumping it is probably blowing off a pressure relief which will cause a lot of heat and load the engine down.

My thoughts also, I see alot of this in the forrest industry. The compensator gets crap in it and will not let the pump destroke so it has to push the fluid somewhere and that would be over the relief like Deano said. What machine is it for a start. CJ

 

[Scott Armst]

It is a komatsu tlb. Where do I find the compensator to clean it? Is it in the pump or attached?

 

[bigdeano]

It is a komatsu tlb. Where do I find the compensator to clean it? Is it in the pump or attached?

The pumps I'm familiar with, it's inside the pump. It's a piston that tilts the swash plate as pressure changes. There may be a small plate over the end of it. It may have a tube attached to the plate to supply oil pressure. I'm not familiar with Komatsu pumps, so it may be different than what I'm thinking. Maybe you can find a picture of it on the internet. Sorry I can't be more help.

 

[bigdeano]

Just happened to think of this, if the pump pressure is adjustable, you could try adjusting it down a little. It's apparently too close to the pressure relief setting.

 

[CJONE]

It is a komatsu tlb. Where do I find the compensator to clean it? Is it in the pump or attached?

Usually on the outside attached with a few small allen screws. it will have one or 2 adjusting screws on it. With out knowing what model TLB it is we are just guessing. CJ

 

[CJONE]

Just happened to think of this, if the pump pressure is adjustable, you could try adjusting it down a little. It's apparently too close to the pressure relief setting.

The comp is what adjusts the pressure. They have little spring loaded darts in them and they stick and the pump will overpressure. OR they get something stuck in them then the pump will not build pressure. The comp is what actuates the cylinder or piston that controls the swashplate angle that you were talking about. CJ