Discussion:
Hydraulic pump issue

Hello,

Looking at a Yale forklift fitted with a mazda diesel engine, serial GDP25RDV 2415 year: 1990 model : FL65

The hydraulic pump fitted on the front of the engine under the radiator had a cracked casing. The owner fitted a new pump but when the boom was lifted to the top the shaft of the new pump sheared. Wondering if anyone has a service manual. Looking for a diagram of the hydraulic system, location of the relief valve specifically.

Thanks
  • Posted 7 Apr 2015 19:52
  • By gareth_o
  • joined 26 Mar'15 - 6 messages
  • chillout, United Kingdom
Showing items 1 - 5 of 5 results.
Hi all, We have a 1998 model yale forklift- unable to trace the model number. Have a problem with the hydraulic gear pump part number 9052606-03 and are unable to find a replacement- can any one give suggestions. thanks
  • Posted 13 Sep 2015 15:15
  • By uthra_r
  • joined 13 Sep'15 - 1 message
  • ras al khaimah, United Arab Emirates
no problem NERO45 , i just thought a more defined explanation might be in order, you were on the right track though. :o)

And to add one more thing, the model number of the truck is more likely a GDP25RDN.
  • Posted 8 Apr 2015 21:25
  • By swoop223
  • joined 23 Mar'12 - 3,691 messages
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
Hi Gareth,

Swoop has given you a much better explanation on how to sort this problem than I did. I find I take a lot for granted these days like the fact that most people addressing this site have worked with lift trucks for a while, I see you have just registered on this site. There is nothing more I could add that would improve on Swoops explanation on how to tackle this problem.
Regards Nero
  • Posted 8 Apr 2015 19:08
  • By NER045
  • joined 11 Jan'14 - 137 messages
  • North Yorkshire, United Kingdom
Main pump pressure should be about 2750 to 2800 or there about, i would not exceed 3000 psi though.
Like was suggested, T into the main line coming out of the hydraulic valve with a 5000 psi guage. Rev up the engine to max rpms and slowly pull the lift lever. after the mast tops out Watch the guage and see what pressure is. If it looks like it will exceed the 3000 psi mark stop and check the relief valve on the first section (inlet section) where the lift spool is located.
It will look like a cartridge valve with a cap on it, remove the cap, loosen the lock nut on the adjusting stem to make any needed pressure adjustments.
Loosen to lower pressure, tighten to increase it. Once you reach the desired pressure lock the locknut down and reinstall the cap.
If the pressure does not change when adjusting the the relief valve is damaged and should be replaced (not repaired).
  • Posted 8 Apr 2015 03:43
  • Modified 8 Apr 2015 03:46 by poster
  • By swoop223
  • joined 23 Mar'12 - 3,691 messages
  • North Carolina, United States
You've been swooped!
swoop223@gmail.com
Hi Gareth,

As I recall I don't think the pump itself has a relief valve, and is totally depended on the relief valve on the hydraulic hoist control valve assembly being set correctly. I haven't any tech info now on this truck so I would screw a test gauge into hoist control valve and check the pressure setting. It needs checking anyway just to see that it has not been screwed down tight. I would set it to 1800 lbs.

Regards Nero
  • Posted 8 Apr 2015 01:02
  • By NER045
  • joined 11 Jan'14 - 137 messages
  • North Yorkshire, United Kingdom

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