Options for dealing with pressure build up in disconnected hydraulic lines

[J_J]

Preventing the possibility of significant pressure build up is actually the most simple and least wasteful. Bleed a teaspoon or so from each line immediately after disconnect into a catch container or onto anyplace needing lubrication. No tool needed. Dont even need to then plug the lines together.
larry

Don't understand what you are saying here

How does one bleed a hyd circuit with out taking things apart. That is what you do if you can't push in on the ball or poppet in the QD.

As far as connect under pressure, I think that some people misunderstand what that means.

Some QD are designed to connect under full pressure, upwards of 3000 psi, and other QD will allow one to connect up to a static pressure to maybe 500 psi. Sometimes the pressure rating for connecting under pressure is for one half of the QD.

This coupler reads like this.

Male coupler will connect under residual pressure up to 3571 psi.
Female coupler will connect under residual pressure up to 1595 psi.
Mating coupler must be without residual pressure.

ISO 16028 Connect Under Pressure Couplers

So the answer is not as simple as it sounds.

Some people seem to not have a problem and others have great difficulty in connecting hyd couplers. Some have even used mechanical devices to attach the couplers.

It all has to do with static pressure, caused by a temp differential, or if you have well made and tight hyd components, they may hold a static pressure when the hyd supply is shut off such as a valve closing.

The weight of a bucket of loader arms may cause a static pressure.

 

[SPYDERLK]

Preventing the possibility of significant pressure build up is actually the most simple and least wasteful. Bleed a teaspoon or so from each line immediately after disconnect into a catch container or onto anyplace needing lubrication. No tool needed. Dont even need to then plug the lines together.
larry

Don't understand what you are saying here

How does one bleed a hyd circuit with out taking things apart. That is what you do if you can't push in on the ball or poppet in the QD.

[snip]

The weight of a bucket of loader arms may cause a static pressure.

By pushing in the check ball or poppet on the coupler tip immediately after it is removed.

That would be a problem, and such implements should be mechanically blocked to stable position during removal.
larry

 

[CJONE]

By pushing in the check ball or poppet on the coupler tip immediately after it is removed.

That would be a problem, and such implements should be mechanically blocked to stable position during removal.
larry

SPYDER, I think what we are trying to tell everybody is falling on deaf ears. CJ

 

[kco]

SPYDER, I think what we are trying to tell everybody is falling on deaf ears. CJ

Not entirely--I did this the last few times and it works great. I have an end cap for 2" steel pipe that I push the coupler ball into to catch the small amount of oil. I need to make sure there is a bit of extra height between the loader arm and mounting bracket before draining the bit of oil as the arm settles an inch or two, but it is still stable on the legs and high enough to drive back in while remounting the loader.

Thanks for the tips.

 

[CJONE]

Not entirely--I did this the last few times and it works great. I have an end cap for 2" steel pipe that I push the coupler ball into to catch the small amount of oil. I need to make sure there is a bit of extra height between the loader arm and mounting bracket before draining the bit of oil as the arm settles an inch or two, but it is still stable on the legs and high enough to drive back in while remounting the loader.

Thanks for the tips.

:thumbsup: Before doing this with a loader, shut the tractor off and move the lever into all the positions a few times that will relieve most if not all of the pressure before you disconnect. CJ