Hydraulic line question

[c4cruiser]

Finally, the MaxJax install is done and got the hydraulics bled. So I pour a beer or three to celebrate and started to remove the lines to put the pump cart away. I go to one of the quick disconnects and find there is a very slight leak at the threads I attached this female QD fitting using liquid teflon just like all of the others and it's the only one leaking.

So my question is what happens when I remove the fitting to fix the leak? I would expect that there will be air (void) introduced once I remove the fitting. Because the fitting is at the bottom of the hydraulic cylinder for that post, will I have to re-bleed that cylinder and if so, how much fluid will be lost?

Also, can I use some swivels on the hydraulic lines? The supplied hoses seem to have a natural "twist" to them and it's next to impossible to get the lines to lay flat on the floor.

Here's the installed lift:

 

[Silver6.0]

You might try to tighten it more right now without taking it apart yet. If you take it apart look to see if either of the ends are cracked causing the leak. I like to use permatex hydraulic pneumatic sealant on hydraulic lines instead of teflon. Haven't had any leaks yet and also it's not gummy like the teflon so it won't block hydraulic ports and valves if it gets in the system during assembly.

If you see that the male end is not cracked cap the line with a plastic plug to prevent fluid loss. Plugs probably came with your kit or use a pipe plug. I would think it wouldn't take much to bleed after the fix if you cap it while making the repair.

You can use swivels as long as they are rated for your psi. I don;t know what hoist's run for psi but a hydraulic fitting supply, napa, or tractor dealer might be able to get you the right swivels.

 

[blk00ss]

My understanding is you do not use Teflon on hydraulic fittings. Their flared and make a permanent seal.

 

[Silver6.0]

My understanding is you do not use Teflon on hydraulic fittings. Their flared and make a permanent seal.

JIC is a common hydraulic fitting end where no sealant is used which is probably what you are referring to.

The QD ( quick disconnect) the op is talking about commonly use pipe thread ends which require a sealant to complete the connection.

 

[koditten]

Take it apart and redope it. I like to use the pipe dope that is specified for natural gas fittings. For some reason this dope doesn't break down as fast as the regular teflon pipe dope.

As long as you know the pressure is off the line before you remove the quick connect, you can remove the fitting and redope and reassemble. Any air that you will introduce when you do this job will be no issue. When you pressurisze the line, the air will be compressed and become part of the oil. Remember, air can be compressed, but a fluid can not. the air will flow with the oil back to the resivior and bubble out when you release the pressure. Kinda like soda pop.

I hope I made my point, The power just now went out. God, I love my automatic standby generator. Sorry, I'm kinda excited. Had this thging for 5 years and this isa the first time it has been used in an ougtage.

KO

 

[Oldbear]

JIC is a common hydraulic fitting end where no sealant is used which is probably what you are referring to.

The QD ( quick disconnect) the op is talking about commonly use pipe thread ends which require a sealant to complete the connection.

The warranty on our box hoists is void if we use tape... we use pipe dope and the better hydraulic sealant on our oil rigs...

 

[Schleprock]

The 2 main problems with teflon tape is
1) People use way too much and end up splitting the female receiver
2) People are careless and will partially cover the openings which then tears off travels around the system plugging orifices and picking up contamination and turning into a hard chunk of filings that can take out your piston pump/motors.

Just to make sure you have released the pressure just give the ****** a quick rap and it will be good to go.

 

[ket-tek]

I switched to nothing but 545 about 10 years ago for all npt hydraulic and hard piped air fittings. Haven't had a single issue yet.. Several lift installs, air suspensions/tanks, shop air compressor installs, replaced every hydro hose on my tractor and loader. no problems.