what causes loader bucket to drop?

[perryn]

Just bought 580k case backhoe . works well except hydraulic bucket cylinders allow bucket on loader to drop when not in use. I see no fluid leaks and the lift arms do not do this. What could be the cause, are there seals that can leak and allow fluid to bleed back into reservoir? Since I have 2 cyllinders on bucket does this mean that both are leaking since I would have thought one would hold it if no material in bucket?

Any help appretiated... Perry

 

[MrJimi]

Welcome to TBN
Lots of things could cause your problem, age, wear and amount of time to come down, like watch it or come back in 2 hours and it went down an inch, lots of variables to deal with.
There are lots of hydraulic experts here and they will chime in
Jim

 

[dqdave1]

spool valves leaking down

 

[Wayne County Hose]

99.99% of the time this is caused by your cylinders leaking internally. Inside the cylinder are two oil seals facing away from each other, or, just one rod seal. If just one leaks oil past, oil will flow thru the lines to the other cylinder and cause your dropping.

 

[Mith]

If I am thinking correctly, as the cylinders are connected, only one needs to leak to allow the bucket to drop, as the fluid will move in the pipes between the 2 cylinders.

EDIT, I see WCH said this in his post.....

 

[perryn]

thanks guys ... then is there a way to tell which cylinder is leaking or do I need to replace both sets of seals?

 

[Wayne County Hose]

Do them both. They both have done the same amount of work over their lives. We call them "sister cylinders." You could isolate them and find which one is worse, but don't even bother. Just reseal them both. Is this something you plan on doing yourself? Unless you are pretty good mechanically and have a good set of tools, I would have them done. I can't tell you how many cylinders come to me in a box where people tried but only made things worse. I never fault anybody for trying, but you have to know your limits.

 

[Soundguy]

IF you don't reseal them both, and want to find out which one is the leaker, you could pull the non pressurized line off each cyl ( they should be DA.. one side will be pressurized when it is curled.. remove fitings from each cyl and see which one dribbles.

You might be surprised to see them both dribbling.. though perhaps one more than the other.. etc.

Soundguy

 

[perryn]

Thanks based on that I guess I will pul both and bring them to a PRO, I'm mechanically inclined but I know my limits.