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  • Hydraulic cylinder help

    I have an old Ford Highboy pick-up. It has a hydraulic ram used for power steering assist. I recently cut it apart to find the inner sleeve that the piston rides in distorted and blown out. The ram rod was also a bit bent. I made a new sleeve slightly smaller and cut the piston down to fit. I used a 304 stainless rod polished as a new ram rod. After welding the assembly back together I put it on the truck. Within less than 2 dozen cycles back and forth it seized.

    I pulled it back off the truck and cut it open again. I found that the ram rod had galled and seized in the head. Stuck serious like..... I'm gonna have to use a press to free it. The hydraulic pressure couldnt budge it and even blew out the end seal trying, distorting the snap ring and washer severely.

    The head has about 3 inches that the rod rides in, hydraulic pressure on one side, and an end seal on the other. The far end of the rod is supported only by the piston. The rod is 5/8 diameter. The head appears to be steel of a pretty decent grade. It didn't look quite like stainless tigging it back together but it isn't very rusty either.

    I have enough 5/8 stainless to make 1 more rod. I'm thinking that I may put a bronze or brass sleeve in the head to try to prevent another galling fiasco. What say the experienced cylinder rebuilders? Am I doomed trying to use stainless for the ram rod? Will the bronze/brass sleeve work, or is it not worth trying. I don't mind the work, but don't have the money for expensive fixes. Rebuilt cylinders are 3-400$, and pretty much totals out the truck.

  • #2
    Originally posted by Duckmang View Post
    I have an old Ford Highboy pick-up. It has a hydraulic ram used for power steering assist. I recently cut it apart to find the inner sleeve that the piston rides in distorted and blown out. The ram rod was also a bit bent. I made a new sleeve slightly smaller and cut the piston down to fit. I used a 304 stainless rod polished as a new ram rod. After welding the assembly back together I put it on the truck. Within less than 2 dozen cycles back and forth it seized.

    I pulled it back off the truck and cut it open again. I found that the ram rod had galled and seized in the head. Stuck serious like..... I'm gonna have to use a press to free it. The hydraulic pressure couldnt budge it and even blew out the end seal trying, distorting the snap ring and washer severely.

    The head has about 3 inches that the rod rides in, hydraulic pressure on one side, and an end seal on the other. The far end of the rod is supported only by the piston. The rod is 5/8 diameter. The head appears to be steel of a pretty decent grade. It didn't look quite like stainless tigging it back together but it isn't very rusty either.

    I have enough 5/8 stainless to make 1 more rod. I'm thinking that I may put a bronze or brass sleeve in the head to try to prevent another galling fiasco. What say the experienced cylinder rebuilders? Am I doomed trying to use stainless for the ram rod? Will the bronze/brass sleeve work, or is it not worth trying. I don't mind the work, but don't have the money for expensive fixes. Rebuilt cylinders are 3-400$, and pretty much totals out the truck.

    When I worked in this industry (a long..... time ago) the rods were high tensile steel, polished, hard chrome plated and then ground to size

    NzOldun

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    • #3
      And the aforementioned hard chromed and ground steel doesn't cost much, especially in the smaller sizes. In here it is sold under the name Cromax.
      Amount of experience is in direct proportion to the value of broken equipment.

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      • #4
        Just a wild guess, but you might find a rod suitable to use in a junk McPherson strut out of a front wheel drive car. A lot of times they are found in the junk pile behind most auto repair places.
        James

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        • #5
          One thing that I can think of from my experience with hydraulics on heavy equipment - be sure your ground has a good contact on the same metal part you intend to weld on. It is very easy to arc across the head to the rod in a hydraulic cylinder.
          Larry - west coast of Canada

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          • #6
            " I used a 304 stainless rod polished as a new ram rod...Within less than 2 dozen cycles back and forth it seized...I found that the ram rod had galled and seized in the head."

            As others have said, don't use stainless as galling is what it does best. If it's a seriously low buck job, use a piece of ground mild steel and make sure the truck is always parked with the wheels turned in the right direction [with the rod inside the cylinder.]

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            • #7
              Originally posted by J. Randall View Post
              Just a wild guess, but you might find a rod suitable to use in a junk McPherson strut out of a front wheel drive car. A lot of times they are found in the junk pile behind most auto repair places.
              James
              Ha, the tube I used to repair the internal portion of the cylinder came from a Mcphereson strut. Unfortunately the rod from that strut was too large in diameter. My plan is to go to the pull-n-pay tomorrow with a micrometer to try to find a strut or shock with a shaft near my diameter.

              Question, when I re-do the bore the ram-rod rides in... what sort of clearance should I be looking for?

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              • #8
                Originally posted by jim davies View Post
                As others have said, don't use stainless as galling is what it does best. If it's a seriously low buck job, use a piece of ground mild steel and make sure the truck is always parked with the wheels turned in the right direction [with the rod inside the cylinder.]

                I didn't realize it would gall as readily as it did. Considering it had ATF under pressure for lubrication I thought it would be ok. I didn't figure it would wear as well as a hardened chrome shaft, but damn. It seemed that there shouldn't be that much side loading in the configuration it works in. My original concern was whether the stainless was strong enough to not bend. Galling didn't even cross my mind. Live and learn.

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