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Mast drift and hydraulic schematic

Hi all.
I have a GP25K with a mast drift (lowering) issue.
It happens in all stages of lift. I repacked the secondary cylinders a year ago. This issue came on suddenly in the last week.
I'm suspecting a load holding valve issue, and I have the parts breakdown for the HCV but they don't list a holding valve in the diagram. Anyone have a hydraulic schematic for this unit they can share?
Thanks.
  • Posted 8 May 2019 00:09
  • By Scrid
  • joined 30 Apr'12 - 40 messages
  • Nebraska, United States
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Hi Swoop,
Its a Cat GP25K / AT17C90291
I didn't get the mast number but the HCV is a 3way.
I think each section has its own load holding valve.
Parts manual calls it a "poppet". I'll probably have to split the lift section out and inspect the poppet and seat for damage / debris, or a broken spring.
  • Posted 9 May 2019 03:44
  • Modified 9 May 2019 03:44 by poster
  • By Scrid
  • joined 30 Apr'12 - 40 messages
  • Nebraska, United States
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whats the truck serial number?
and a mast number, (look on the right hand side about half way down or just under the tilt cylinder yoke mount) it should be stamped there.
  • Posted 8 May 2019 11:31
  • Modified 8 May 2019 11:31 by poster
  • By swoop223
  • joined 23 Mar'12 - 3,692 messages
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
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