Hydraulic help

[fiveoford89]

I have a mid 80's case backhoe. As I operate the backhoe portion of this machine I sometimes lose Hydraulic pressure which causes the boom fall. When it does this it happens slowly. When I operate the proper lever, pressure will return and I can pick up the boom without a problem (I shouldn't say without a problem, it seems as though it takes alot more from the pump to get it back up but it does go up). When I use the front loader I have no issues and it works perfectly. Does anyone have any ideas what can cause this? I have checked my fluid levels and they appear to be fine. Any help or ideas would be greatly apprieciated. I should also say that the rate in which the boom falls differs depending on where I leave it. If I go half way it hold for approximately 5-10 seconds then it will slowly fall. The further down the boom goes, the less it holds and the faster it falls :thumbsup:

 

[jake98]

Welcome to TBN. We have a hydraulics forum, you should try your ? there.

 

[J_J]

Install a hyd pressure gage in the system, and it will let you monitor and trouble shoot the hyd system.

Are you saying that if you raise the boom and return the levers to neutral, the boom will fall? By returning the levers to neutral, the spool blocks the fluid from the cyl. If the boom is slowly falling, then the cyl must be bypassing, or the spool for the boom is leaking. When the cyl is fully extended, does the relief activate.

 

[fiveoford89]

JJ - thank you for responding- the boom falls when I return the lever to the nuetral position- also the main boom- I believe it's referred to as the shoulder, is the one that fails- the other hydraulics seem to wok just fine, I'm not sure if this may be some sort of indication to the problem

 

[KWentling]

Do backhoe valves have load checks? If so, I would guess that would be the problem.

Kim

 

[638]

If it doesn't do it every time, then I would look for the valve not returning to center each time. Perhaps a broken or weak spring in the valve, or the linkage needs lubed.