squash plate hydraulic pumps.

[gunracer1]

i have a Liebherr dozer 712 i think. i have had for years, and i have been ignoring it for way to long. it was working fine the one day then no drive the next time it was fired up. i have swapped hydraulic lines around and made the drive work, i have swapped the control wires around to test everything out. and best i can tell it is the squash plate pump is stuck. is it very hard to pull one apart? its easy enough to get to and remove it.

 

[larboc]

Squash?

 

[gunracer1]

Squash?

I'm a tard, apparently i typed in Texan.

 

[ThePanzerFuhrer]

Check your pilot system before you dig into the pump. On these high efficiency machines the pump will not swash until you call for power.

Had this issue on a 744h. A orfice fell out of the pilot pressure system. Found it by measuring the pilot pressure.

 

[Bacho]

i have a Liebherr dozer 712 i think. i have had for years, and i have been ignoring it for way to long. it was working fine the one day then no drive the next time it was fired up. i have swapped hydraulic lines around and made the drive work, i have swapped the control wires around to test everything out. and best i can tell it is the squash plate pump is stuck. is it very hard to pull one apart? its easy enough to get to and remove it.

I’ve pulled a handful apart and put them back together successfully. I can’t comment on your symptoms though

 

[Provience]

Sounds like you are talking about a piston pump?

 

[gunracer1]

Check your pilot system before you dig into the pump. On these high efficiency machines the pump will not swash until you call for power.

Had this issue on a 744h. A orfice fell out of the pilot pressure system. Found it by measuring the pilot pressure.

the pilot system seems to work the other side just fine. but i will check it out.

 

[SLOWPOKE693]

the pilot system seems to work the other side just fine. but i will check it out.

So you are getting pilot pressure to the spool valve at the distributor, the spool valve is moving but you get no movement at the track? If so, it sounds like an issue with the load sense line or valve that controls the pump. Don't go pulling the pump apart until you can confirm how the system works. It's very possible your problem is outside the pump