Air Leak In Tilt Cylinder Hydraulics?

[Hilbilly]

I've been having an issue with the hydraulic top link cylinder and I really notice it when using ground engaging implements and my heavy snow blower. It seems to be an air leak. I watch the cylinder ram extend and retract as I drive along, with no input from me. If I stop and cycle the cylinder to relief in both both directions then the air will bleed out but after a short period of use the problem comes back.

I'm pretty sure I have an air leak but don't understand how air can get in but hydraulic fluid doesn't leak under pressure. Any ideas on how to find the leak, when there is no hyd fluid leak visible anywhere. Also how to tell which side of the cylinder system to check.

 

[LD1]

What brand is the cylinder/toplink and what brand is the valve and how old are they.

What size is the cylinder for the toplink?

 

[oldnslo]

Sounds you have a small leak in the directional valve controlling the top link. The weight or force from heavy implements puts pressure on the top link and any oil leak across the directional valve creates an air pocket in the cylinder. Load holding valves on cylinder will reduce or eliminate this but then you lose float.

some companies make valves with mechanically operated checks but these are not common on ag equipment

 

[Hilbilly]

This is a link to the top link I used.
https://www.princessauto.com/en/top-link-cylinders/product/PA1000000426

Here is a link to the diverter valve I used.
https://www.princessauto.com/en/12v-dc-2-position-6-way-selector-valve/product/PA0008051799

Here are some pics of the setup. I took one of the rear remotes and ran it into a diverter valve and split that flow between 2 circuits. One to operate the top link and the other to operate my snowblower chute or the rear tilt gauge wheel cylinder on my landscape rake.

I forgot to mention these valves are only one year old.

 

[LouNY]

If it is indeed an air leak it would be when the lines or connectors had a negative pressure on it.
That will allow air to enter a system but it may reseal with pressure on it.
It can happen with quick connects and valves around the 0-ring seals.
If you add a lock to the top link it could stop the problem;

You can also get hydraulic top links all set up with one;

either of these could likely clear up your issues.

 

[Hilbilly]

If it is indeed an air leak it would be when the lines or connectors had a negative pressure on it.
That will allow air to enter a system but it may reseal with pressure on it.
It can happen with quick connects and valves around the 0-ring seals.
If you add a lock to the top link it could stop the problem;
View attachment 722034
You can also get hydraulic top links all set up with one;
View attachment 722035

either of these could likely clear up your issues.

Thanks for the info.

I can't find a top link with the built in lock valve. At least none that are available.

Is a lock valve the same thing as a check valve? If so maybe I can find one of those to try.

 

[MtnViewRanch]

Curious, have you used the diverter? Every solenoid diverter I have ever seen always was fed from the left side.
I'm not saying this is your issue, I doubt that it is. Just curious if the 2 sets of couplers operate properly.

As far as your air issue, I doubt that is the problem either. Very common to have the rod extend faster than the fluid going in thus creating a vacuum. Typically flow restrictors will solve this issue.

One last thing, have you checked the fluid on the dip stick to see if it is aerated?

Good luck.

 

[LouNY]

Are you looking for a Cat 1 or a Cat 2 top link?

cat 1 Surplus Center

2x8.25x1.18 Category 1 Hydraulic Double Acting Top Link Cylinder AMA 06003​

item number: 9-7682-08 PRICE: $219.85

cat 2 from Agristore well over a dozen to select from

Category 2 Hydraulic Top Link 16 15/16" - 23 1/4"​

 

[Hilbilly]

Curious, have you used the diverter? Every solenoid diverter I have ever seen always was fed from the left side.
I'm not saying this is your issue, I doubt that it is. Just curious if the 2 sets of couplers operate properly.

As far as your air issue, I doubt that is the problem either. Very common to have the rod extend faster than the fluid going in thus creating a vacuum. Typically flow restrictors will solve this issue.

One last thing, have you checked the fluid on the dip stick to see if it is aerated?

Good luck.

Thanks for replying Brian.

I have used the diverter for over a year and it works fine. At least all of the functions work correctly.

I'm not sure what you are suggesting is not the issue. Are you referring to the diverter?

I haven't checked the dipstick but will the next time I use the tractor. Good point and thanks.

I was told by the hydraulic guy at Princess Auto not to use flow restrictors, when I was trying to reduce flows to the tilt cylinder for the FEL brush mower I made. He said something about, when the flow is going into the bottom (large volume) side of the cylinder there is a back pressure created in the ram side which was causing seals to blow in their cylinders. Have you experienced anything like this and does it make sense or not.

What size flow restrictors do you use on Kubota L6060's and do you sell / ship them to Canadians?

 

[Hilbilly]

Are you looking for a Cat 1 or a Cat 2 top link?

cat 1 Surplus Center

2x8.25x1.18 Category 1 Hydraulic Double Acting Top Link Cylinder AMA 06003​

item number: 9-7682-08 PRICE: $219.85
View attachment 722047
cat 2 from Agristore well over a dozen to select from

Category 2 Hydraulic Top Link 16 15/16" - 23 1/4"​

View attachment 722048

Thanks Lou.

I'm looking for something in Canada, if possible, to avoid the delays and costs of getting things across the border. Especially now that my area is essentially cut off from the main supply hub in BC. After the recent flooding and mudslides, all the routes to the interior of the Province from the Lower Mainland have been cut off, except for one that was recently reopened but only 2 lanes and only for essential travel. I see Surplus Center usually stocks valve kits for their top links but is out of stock at the moment. That might be something for me to pursue or see if I can find something like that in Canada. Or use some flow restrictors, as Brian does for his systems. I might be able to source those locally.