Cat 268b hydraulic fan not turning

[talknfast]

Skid steer just stopped and wont move the hydraulic fan isn't turning does that mean its the pump that's out????

 

[Nige]

Do you have any warning lights lit up or buzzers bleeping at you..?

 

[caterpillarmech]

Could be your pump drive coupling. I don't think it will have any lights on if the coupling goes. Should still be able to turn off the park brake solenoid but it won't be controlling any pressure. The fan motor is usually the dead giveaway as its pump is at the end of the stack.

 

[Mobiltech]

X2 on the pump drive coupling. When a skidsteer stops moving the first question I ask is if the fan is turning.

 

[Jacob277D]

Say I have a similar situation but my fan spins but slowly only about 200psi of charge pressure when throttle is maxed out. The fan will almost ramp in various speeds while idling. New charge pump but same issue. Could the piston pump be pulling all the oil starving the fan pump? I’m also debating if I have a stuck flushing valve on a motor but no information on how to test for that. Should the fan be easy to spin when not hooked up to anything?

 

[Zewnten]

Probably have to replace your charge relief valve first. But for more accurate information and help provide the serial number.

 

[Jacob277D]

FMT00336. I pulled the relief valve to inspect it. It still had the original paint on it. Do the springs get weaker with age?

 

[Zewnten]

If you have low charge pressure replacing the relief is usually the first step.

 

[Jacob277D]

Did that still nothing. I did test the piston pump case through the top port and I have nothing so I am thinking the lip seal is gone on the piston pump but I don’t know if that will effect charge pressure.

 

[Zewnten]

I’d be leaning towards your charge pump being bad. If I’m remembering correctly the only thing in that circuit is the pump, the fan motor, and the relief. I don’t remember a seal on the charge pump between the piston pump and charge just an input shaft.

 

[Jacob277D]

Brand new charge pump from caterpillar. I checked no seal just an o-ring. I’m thinking I have problems in the piston pump for the motors “hystat” I’m currently looking for the L1 location for testing the case pressure. I’m really at a loss on this thing it’s been 3 weeks trying to get it out of my trailer might just chain it to a tree and drive off.

 

[Zewnten]

Unfortunately I can’t find that port either just case drain ports towards the input shaft.

 

[Jacob277D]

Yeah, I’m going to tear down all the pumps this weekend I’m done looking for the easy stuff hopefully I find the problem.

 

[Jacob277D]

Do you happen to know what size of plug it would take for the ABCD ports on the hystat? I’m looking to ship it off and have it gone through but I want plugs in it.

 

[Zewnten]

Sorry I don’t. I always use the blue plugs cat sells.

 

[Jacob277D]

I have figured out my issue I have a stuck flushing valve in the right final drive motor.

 

[Zewnten]

I have figured out my issue I have a stuck flushing valve in the right final drive motor.

Debris?

 

[Jacob277D]

Has to be I have to get it off to see. Instead of establishing a baseline for the system following the checklist I went straight to checking the front and rear rotating groups and the right side pressure was extremely low. About 1700psi and I could see the cooling line stiffen up. It could just be the relief valve as well I pushed low psi oil back through the return to cooler or case line and the fluid came out of the disconnected motor lines. Hence the reason for no charge pressure it was dumping back to the cooler through the loop system on the right side and through the relief valve because the flushing valve could not change state from low pressure.