CAT 248 No hydraulics

[Jeff Geiwitz]

Need some help with this one. I was simply back dragging millings and machine stopped like I lifted the safety bars. No movement or lift. No signs of weak or winning pumps. I can start the machine pull the safety bars down hit switch and light goes off, but still no movement. Pulled the motor and the lovejoy/plate teeth are fine. Is there a solenoid that could be preventing hydraulic pressure? I also noticed the radiator fan is not spinning which is controlled by hydraulic pressure. I really hate to pull the pumps and find out it was something electrical. Any guidance would be greatly appreciated!

 

[Nige]

Please post a Serial Number to identify the correct electrical schematic.

Pulled the motor and the lovejoy/plate teeth are fine.

Did the splines in the centre of the coupling look like this photo.?
Post a photo of your if you have one.

 

[Jeff Geiwitz]

Serial CAT00248C6LZ01366

 

[Nige]

Check the Hub #5 that is mounted on the hystat pump input shaft. In your photo there appears to be some minor damage right on the end of the coupling splines. Has the hub by any chance slid along the shaft and lost connection with the splines in the coupling.?

 

[Jeff Geiwitz]

I think the white spots might be from wiggling the motor to get it to detach from coupler 5. Coupler 5 seems to be tight on the pump , no movement back and forth.

 

[Nige]

Need som more input from others in that case. Nothing particularly comes to mind if the coupling is good and the hub hasn't moved.

 

[Deimos]

Need some help with this one. I was simply back dragging millings and machine stopped like I lifted the safety bars. No movement or lift. No signs of weak or winning pumps. I can start the machine pull the safety bars down hit switch and light goes off, but still no movement. Pulled the motor and the lovejoy/plate teeth are fine. Is there a solenoid that could be preventing hydraulic pressure? I also noticed the radiator fan is not spinning which is controlled by hydraulic pressure. I really hate to pull the pumps and find out it was something electrical. Any guidance would be greatly appreciated!

Your machine has a faulty gear pump. Either the pump drive has been cut off or the pump is very worn out.

 

[Nige]

If he has no dirve or implement hydraulics then the illustration below is the combined hystat power train pump and work tool pump. The hystat pump is shown in silhouette between the work tool pump #1 and the engine flywheel housing.

Input shaft to the hystat pump (2nd illustration) sheared.?

 

[Jeff Geiwitz]

Well, it was the charge pump. splines are gone on the pump shaft. The drive gear has spline damage too. unable to locate this anywhere. We can find the pump. Any ideas where to locate the drive gear? I attached some photo's.

 

[Nige]

Is that part listed separately on the parts illustration.? If not then it is not available separately, only as part of a larger component.

 

[Jeff Geiwitz]

Nige, It goes where the red arrow is, connecting the pump to a gear in the motor. I only see the pump listed on CAT parts. When I search charge pump gear it only shows the pump.

 

[Nige]

Try looking for the front gear group.

 

[Deimos]

Nige, It goes where the red arrow is, connecting the pump to a gear in the motor. I only see the pump listed on CAT parts. When I search charge pump gear it only shows the pump.View attachment 359276

I was right in assuming that the charging pump or its drive had failed. The splined connection in these pumps is a weak point, and it often strips the splines.

 

[Jeffrey Geiwitz]

I was right in assuming that the charging pump or its drive had failed. The splined connection in these pumps is a weak point, and it often strips the splines.

Yep, you nailed it. We have a replacment pump, but that drive gear is no where to be found. I don't even see it listed on CAT parts website, to at least get a part number.

 

[Nige]

See my earlier suggestion to look at the “front/timing gear group” in the parts manual. This will be part of the engine not the hydraulic system. If I could get into the system I could probably give you better suggestions, but right now I can’t.

 

[heymccall]

 

[heymccall]

176-0761 .... Cat shows as obsolete.