Hydraulic Piston Problem

[Reid LeSage]

I own a landscaping company and I got this idea to get a mast off of a forklift and turn it into a lift for my mowers. Sounds easy haha. I got my hands on an old clark mast all complete. I put a hydraulic pump on it off of a power lift gate. It was working fine and them it started leaking at the top. This mast had been sitting outside for sometime. I took it apart but I cant find any numbers on it. I had a couple of friends look at it (they have some experience with hydraulics) and they both said that they have never seen anything like it.
On the top it has three allen bolts those release a plate with the wiper in it,under there you remove three cresent shaped bars that hold down a large plate. That will allow you to remove the rod. at the bottom of the rod is a large round rubber seal that is held in by 6 bolts. does this sound familiar to anyone? I am trying to get a seal kit but not having any luck

 

[Junkyard]

I would imagine a good seal place can match them up. I’ve resealed some oddball stuff by taking seals and parts there so they can measure and either replace with a like for like seal or we have gotten creative and come up with something that does the job. The odds of identifying the cylinder and finding a “kit” are slim.

 

[Theweldor]

Start searching "Hercules Hydraulics" You will need some dimensions of what you have. Might take bit of searching but they will have it.

 

[John C.]

Just a thought while reading your description of the cylinder and the pump. Conventional fork lift mast cylinders are generally single acting. That is you put oil to the piston side of the cylinder and nothing but air comes out the other end. There is a hose at the top of the cylinder to let any oil leaking past the piston go back to tank. The forks come down on gravity when the valve spool is shifted to allow oil from the piston side of the cylinder to go back to the tank. I don't recall if power lift gates work that way or not.

 

[Reid LeSage]

yes John I believe you are correct about the top hose only being a vent. Thanks I will work on that problem after. So far all that I can find is a seal called "Leather Cup Seal Gasket part number 623598" it looks like the correct part but I cant find the specs on it and so far that number has not helped me get and other numbers. I will keep looking. Thanks everyone for your help so far.

 

[Reid LeSage]

here is a pic of the seal that I have

 

[Reid LeSage]

and this

 

[TD24]

Have you found your parts or the info on the upright to get then?

 

[Reid LeSage]

no luck so far I went to a hydraulic place and was told that I was wasting my time looking for it. He offered to rework the piston to and up to date seal but its rather expensive. So I will keep on looking hopefully this does not become a boat anchor

 

[Theweldor]

There are a few oddball seals that are obsolete. The other option is to get updated ones of the same outer dimensions and have a new piston head machined to fit your rod and accommodate the new seals. If you have a machine shop you deal with it would not be a problem to whip one up.

 

[TD24]

Email me direct: forktruk@yahoo.com.
Can get you the info you need.

 

[Reid LeSage]

email sent thanks

 

[Reid LeSage]

Here are the seals with a tape measure as best I can measure the cylinder diameter is aprox 5.25'

 

[Reid LeSage]

the seal is leather

 

[RZucker]

You need measure the bore of the cylinder. Any Hydraulic shop that has any knowledge of anything should know what a blank cup seal is... it will look the same as what you have but the holes will have to be custom cut/punched.

 

[Ronsii]

That is pretty common for a lift mast that is out in the weather from time to time, eventually rain water gets in the top and starts to rust the cylinder and because most fork truck operators don't usually go to the maximum lift of the mast once in a while the cylinder eventually gets extremely rusted and pitted inside and will put extreme wear on the seals when it finally does get used a bit higher than normal.


Some very good advice I got from a cylinder rebuild shop is always cycle the mast top to bottom a couple times a month especially if it sits outside


One other thing... your cylinder will more than likely have to be honed a good amount otherwise your new seals will just get eaten up.

 

[RZucker]

That is pretty common for a lift mast that is out in the weather from time to time, eventually rain water gets in the top and starts to rust the cylinder and because most fork truck operators don't usually go to the maximum lift of the mast once in a while the cylinder eventually gets extremely rusted and pitted inside and will put extreme wear on the seals when it finally does get used a bit higher than normal.


Some very good advice I got from a cylinder rebuild shop is always cycle the mast top to bottom a couple times a month especially if it sits outside


One other thing... your cylinder will more than likely have to be honed a good amount otherwise your new seals will just get eaten up.

A nice rubber flap to divert rain water from the top of the cylinder is a great idea.

 

[Ronsii]

^^ Yep, I have often thought that myself.... now if I could just get myself to do it I'd be all set....