wdchyd
Elite Member
If you had QC's after the pump then definetly I'd put in an extra PRV inline
Blew up hydraulic pump on Yanmar 4220 D.
- Thread starter Gary Fowler
- Start date
- Views: 6663
chriswheeler
Platinum Member
I'd start by cleaning/replacing the suction filter in the hyd oil sump. Once you are sure you are getting clean oil, install the new pump. Before starting the tractor again, would go to the FEL joystick control and remove the large cap that covers the relief valve. ( most are on the bottom of the valve ) I'd open the relief valve until it will hold almost no pressure. You will know you are wide open when the FEL won't operate anymore. Then slowly adjust tighter and tighter until the FEL will just lift the front end of the tractor off the ground. That said, this is a open center hyd system and should bypass to the relief valve in the 3 point when ever the FEL is not used. If the pumps crap out only when using the FEL, I'd work on the relief valve, could be crud from a dirty filter loged into the valve seat. Sure costly to be wrong, $400 a pop + labor. I'm suprised that the key didn't shear in the drive coupling first.
Chris
Chris
J_J
Super Star Member
- Joined
- Sep 6, 2003
- Messages
- 18,952
- Location
- JACKSONVILLE, FL
- Tractor
- Power-Trac 1445, KUBOTA B-9200HST
Does your valve have PB outlet?
What I am thinking is that when the seals were leaking on a stacked valve,or a mono blocked valve, and you tighten down to much on the valve, you caused stress and the next action cracked the valve.
Only other thing I can think of is if the relief poppet was rusted closed and never opened when the cyl was maxed out.
If there were debris in the relief, keeping it open, there would be some fluid flowing.
Do you know the relief pressure psi, and was it set correctly.
What I am thinking is that when the seals were leaking on a stacked valve,or a mono blocked valve, and you tighten down to much on the valve, you caused stress and the next action cracked the valve.
Only other thing I can think of is if the relief poppet was rusted closed and never opened when the cyl was maxed out.
If there were debris in the relief, keeping it open, there would be some fluid flowing.
Do you know the relief pressure psi, and was it set correctly.
OP
Gary Fowler
Super Star Member
- Joined
- Jun 23, 2008
- Messages
- 11,917
- Location
- Bismarck Arkansas
- Tractor
- 2009 Kubota RTV 900, 2009 Kubota B26 TLB & 2010 model LS P7010
I talked to my brother in law yesterday and the new pump is installed and all is working fine. He had a mechanic rebuild the FEL joystick valve. Evidently the way this gray market tractor is plumbed, the only relieve from the pump is the PRV in the joystick which may or may not have been functioning right. From his description of the failure, it sounds like the pump was deadheading when he attempted to raise the FEL the pump just kept supplying oil but none was flowing thru the valve and blew the pump. The PRV must not have been working properly or couldnt handle the flow. Any way with a new pump and rebuilt loader valve, it is back at work.
clemsonfor
Super Member
Good to know, hope it truly is funtioning, id hate to see you spend another $450 on the pump. Did the mecanic give a warrenty to cover pump failure if that was not the cause?
Well glad to hear its working that could have gotten expensive!
My hydraulic system has a built in prv its under one of the plugs in the diverter block by the bell housing. Its shimmed with washers to adjust it. Mine is a smaller tractor than the 4220 by a little bit but I sure would think Yanmar had a pressure relief installed also? (I agree on the afterthefact plumbing btw)
My hydraulic system has a built in prv its under one of the plugs in the diverter block by the bell housing. Its shimmed with washers to adjust it. Mine is a smaller tractor than the 4220 by a little bit but I sure would think Yanmar had a pressure relief installed also? (I agree on the afterthefact plumbing btw)