Hydraulic Flow Restrictor Gets Hot

von-mil · Jun 18, 2015

I recently added a pinhole type flow restrictor fitting to my hydraulic top link. Without it, it was too difficult to make fine adjustments because the cylinder moved too fast. Now that I am using it, I can feel the fitting getting hot and was wondering if this is a problem.

I added the fitting on just one side of the cylinder circuit and this makes obvious the difference in temperature between it and the fittings on the side that I did not alter. The single restrictor fitting works fine in both cylinder directions but I am now wondering if I should add an identical fitting to the other side of the cylinder and if that would have any effect on operation or temperature.

Obviously I won't be constantly adjusting the top link length so there should not be an excessive heat buildup, but it's just something I noticed when playing around with it, testing it out, looking for leaks, etc. Should I be worried or just go ahead and use it?

Thanks for reading.

MtnViewRanch · Jun 18, 2015

The heat becomes a problem when the entire system runs to hot. With the occasional use of the top link, and when I say occasional I mean not using full strokes constantly it will do no harm to the system. Enjoy your now easily adjustable top link.

You did install on the rod end correct?

von-mil · Jun 18, 2015

MtnViewRanch said:
You did install on the rod end correct?

The cylinder has a check valve on it. The check valve has 2 ports. I installed the adapter to the line coming from the port closest to the rod so I think the answer to your question is Yes. (I don't know what goes on inside the check valve)

But - I did not think it made a difference which side I used. Was that an incorrect assumption?

MtnViewRanch · Jun 18, 2015

von-mil said:
The cylinder has a check valve on it. The check valve has 2 ports. I installed the adapter to the line coming from the port closest to the rod so I think the answer to your question is Yes. (I don't know what goes on inside the check valve)

But - I did not think it made a difference which side I used. Was that an incorrect assumption?

For top & tilt cylinders, because of gravity, when using only a single restrictor, it is best to have it located on the rod end of the cylinder which you have done. So you should be good. :thumbsup:

J_J · Jun 18, 2015

If you have say a 10 GPM pump, and you are using full lever, you are maybe passing about 3 GPM thrugh the restrictor, and the other 7 GPM must pass over the relief valve. Things will get hot.

Thing to do is to only use light lever for the top cyl. The restrictor is only going to allow the set amount of fluid through.

The check valve is there to prevent the cyl from drifting. It contains a plunger and spring that will lock the cyl in place until enough pressure is developed to release the check and fluid can flow.