A hydraulic cylinder could be leaking for all kinds of reasons. Let’s face facts, the things malfunction all the time, but how could we blame the cylinders for breaking every now and again? Hydraulic systems are complex; to function correctly, they must make use of many moving parts to complete repetitive work that is both precise and constant. Any working machine would fail from time to time given those same mechanical demands. So, why might your cylinder be leaking? What are some things to be on the lookout for that might be the cause of your leak? Well…

It could be you’ve been replacing the wiper, not the seal

You’d be surprised how common this mistake is. It’s easy to assume that the first seal looking object in the cylinder is actually the seal. Look at this picture – doesn’t it look like a seal?

hydraulic cylinder

Well, it isn’t. Pictured above is a wiper – the part of a cylinder responsible for keeping sand, dirt, and other debris out of the cylinder. If you want to know how a wiper keeps out all of that debris, go here and read up on it. We are going to shift gears towards why a wiper isn’t a seal. It’s simple actually.

Seal keep stuff in, not keep stuff out

You don’t believe me? Go ahead and click that title. Nowhere in that information does it mention keeping stuff out of the cylinder. Seals specifically work to keep all of the fluid and gas inside the cylinder. They are inherently concerned with pressure control. Take a look at this image:


Notice how the seals in this photo have the ability to press down onto the cylinder, as opposed to sitting on top of the cylinder like a wiper does. Pressing the seals down over the cylinder creates a pressure lock that keeps fluid and gas inside.

Now, don’t get me wrong. It’s important to replace both the wipers and the seals on a cylinder to keep it in working order, but replacing the wiper thinking it’s a seal will cause you to neglect the seal altogether. That will lead to cylinder failure. Knowing the difference between the two will definitely extend the life of any cylinder you maintain.

And, of course, if a cylinder repair is beyond your expertise – give us a call. We are professionals, we can certainly fix any that happens to be wrong with your cylinder. You can count on that.

7 Responses

  1. John Carston
    Apr 21, 2016 - 02:40 PM

    This article has been really helpful for my hydraulic cylinder problems. I can see how common the wiper problem is that you mentioned since they look identical to someone like me who isn’t an expert on this. Thanks for the detailed cylinder article!

  2. Alex Trodder
    Apr 22, 2016 - 07:14 PM

    You make a great point about how seals are essential to pressure control in hydraulic systems. I used to work in a warehouse that had a pallet jack that had a leaky main cylinder. It always too more effort to raise pallets with that jack because the fluid pressure was inconsistent. Thanks for your post about how to properly service and maintain your hydraulic equipment.

    • Kenneth Gladman
      Sep 07, 2016 - 08:10 PM

      You are absolutely right about the importance of functioning cylinders and hydraulic systems. You want to make sure you are getting the most out of your system and energy. With proper care and maintenance it should run efficiently for a long time.

  3. James Bergman
    Apr 26, 2016 - 04:29 PM

    I am surprised that people would mix up the seals and wipers so often. However, I can see why they would make the mistake. I think the best way to avoid making the mistake is to do research on how to replace seals before trying to do it. Another solution would be to replace all of the parts at the connection points when you have to replace one. This way you know that you are replacing the seal and the wiper every time.

  4. Bob Lowe
    Jun 06, 2016 - 11:44 PM

    Thanks for the post. This is really helpful. I agree that Hydraulic systems can be very complex, and can be hard to fix. I really like the idea to consult with a professional, or have them work on it. I think that can ensure that they problem will be fixed the right way.

  5. Braden Bills
    Oct 11, 2016 - 02:35 PM

    It turns out I’ve been replacing the wiper instead of the seal. I’ll make sure I get a professional to help me out in making sure the right one gets replaced! I don’t want any failures to happen.

  6. Ian Johanson
    Nov 17, 2016 - 09:59 PM

    A good rule of thumb is probably to change the wiper and the seal at the same time. I think it will help avoid any confusion between the two and which one needs to be replaced. However, hopefully you are hiring somebody who knows how to handle hydraulic repairs if you don’t know the difference between the wiper and the seal.


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