Back hoe woes

   / Back hoe woes #1  

Pieandapint

New member
Joined
Sep 16, 2017
Messages
3
Location
HIGH PEAK
Tractor
Ih hydro 85
Hi folks,

Got a problem with the McConnel back hoe, so I'll start at the beginning.

Machine worked fine until father-in-law damaged a slew ram, it was left sitting a few months (covered) until ram was replaced.

Hooked everything up to tractor and all front spool valve seals were pushed out and leaking. Just replaced all the valve rod (don't know the correct name) seals and wipers but same happened again.

The spool valve won't operate any of the 3 double acting rams, or the 2 single acting slew rams, it's as if pressure is being applied to both sides of the cylinder at the same time.

I've taken the hydraulic return off the tractor and it's flowing fine, also disconnected a ram from the backhoe but it still fails to operate with no load.

With it being all rams not functioning, I can only assume it's the spool valve that's faulty. But cannot see how it would all of a sudden affect all circuits or what could be causing it. Only adjustment I can see is a slotted screw under a cover with lock nut (prv?), or a slotted screw for setting tension on the valve rod, but assume that just controls the centre position.

Sorry about the long winded post, I am completely stumped but to say I'm an amateur at hydraulics is an understatement!

Thanks guys!
 
   / Back hoe woes #2  
Does it load the engine when you try to move something? Maybe hoses got switched around? Tough problem to diagnose.
 
   / Back hoe woes
  • Thread Starter
#3  
Yeah, but I've double checked all hoses.

Cheers
Dave
 
   / Back hoe woes #4  
Pieandapint
When you say it blew out all the seals on front spools is in the valves for the backhoe? Was this as soon as you started the tractor or when you operate a function? The reason the seals on the valve on being pushed out is because the tank line for this valve is being pressurized. Is this mounted on a tractor with a 3 point hitch? If yes you should have a pressure line, a line from the power beyond port to the 3 point hitch, tank line directly to tank.

The tank line being pressurized would prevent the functions from working
 
Last edited:
   / Back hoe woes #5  
This may sound crazy, but could it be air in the line? Have you loosened a fitting to see ff anything happens when you move the stick?
 
   / Back hoe woes
  • Thread Starter
#6  
Pieandapint
When you say it blew out all the seals on front spools is in the valves for the backhoe? Was this as soon as you started the tractor or when you operate a function? The reason the seals on the valve on being pushed out is because the tank line for this valve is being pressurized. Is this mounted on a tractor with a 3 point hitch? If yes you should have a pressure line, a line from the power beyond port to the 3 point hitch, tank line directly to tank.

The tank line being pressurized would prevent the functions from working

Thank you!
You were exactly right, I had accidently connected the spool valve the wrong way around. Doh!

All working now :)
 
   / Back hoe woes #7  
Thank you!
You were exactly right, I had accidently connected the spool valve the wrong way around. Doh!

All working now :)

Glad you found the problem and reported the results.

Now go dig some holes:thumbsup:
 

Tractor & Equipment Auctions

Kubota RTV500 (A47384)
Kubota RTV500 (A47384)
2021 Harley-Davidson FLHP Motorcycle (A51694)
2021...
2017 TOP HAT TRAILER 16 FOOT UTILITY TRAILER (A53843)
2017 TOP HAT...
2011 Freightliner M2 106 Ambulance (A51692)
2011 Freightliner...
40' High Cube Multi-Door Container (A50123)
40' High Cube...
2014 Ford Explorer Sport AWD SUV (A51694)
2014 Ford Explorer...
 
Top