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Bed Cylinder rebuild


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My bed was getting slow to come back in, especially with a heavy load, the cylinder had a slight leak at the shaft seal.  It was not a drip, just damp all the time.  Everything else was working fine so I felt the pump pressure was good.  Decided to take the cylinder out and get it rebuilt after talking to my hydraulic guy, he felt it could be bypassing internally.  We thought about testing the pressure but with the cylinder leaking anyway I decided to start there.  I had decided to change the pressure line while I had it out.  When I removed the line from the control valve I got a small piece of rubber like material come out in my hand.  The cylinder was not bypassing but the hose had broken down internally and the piece was getting stuck in the bypass valve in the control valve body.


This is an older international and as you can expect the pins were all siezed.  After 8 hours and a TON of heat I got it out.  I ended up modifying a ball joint press so I could heat, take a couple of turn, heat some more.  Both pins fought me until the last 1/1000 of an inch!!


Not sure if someone had put something in the system or not but I ended up changing all the hoses.  My guess is that someone put brake fluid in with the oil in an attempt to swell the seals on the cylinder.  


The message is, don't add shit to your system or the hoses can break down internally as well as the seals and O rings in the rest of the system

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A good friend will bail you out of jail, but a great friend will ...

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Been there, done that, Got the t-shirt.... I feel your pain.. lol

YEARS ago back in my early days of starting out on my own I had bought an old Chevy 1 ton with a eagle intergrated wheel lift body on it. Nothing fancy, Just a good starter truck. and at some point in the trucks life, I am assuming water had gotten into the hydraulic system. The previous owners fix was to pour air brake/air line dryer into the system (For those who dont know, its basically rubbing alcohol that you can pour a small amount into an air dryer/compressor on a big rig in cold weather if you have a frozen air line, brake can etc.. ). He never bothered to mention this to me of course. After a few weeks of running the truck, the hydraulics slowed down and at times got stuck etc... I ended up pulling the return off the valve body just to see what kind of pressure i was getting and what came out of that line looked like roofing tar... the air line dryer fluid had eaten EVERYTHING in the system. Seals, hoses, the clutch pump... It was a disaster... I ended up spending more to rebuild the hydraulic system on that crusty old truck than I had originally paid for it..

My suggestion to you Stubborn would be to give the system another good flushing and fresh fluid/filter after a couple of uses.. I know the expense of the fluid and filter sucks but it is better than all your new hoses and cylinders getting tore up from any contaminants that may still be in the system.


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I am going to flush it one more time, that will make three.  I changed oil and the filter when I started having the issue and again now.


A long time ago, an old timer told me that to prevent freezing in snow plow hydraulics put in a teaspoon full of antifreeze, not dry gas or anything like that.  I have added a teaspoon every time I change the pump oil for years without any issue.  We hook and unhook the power angle cylinders a lot and moisture tends to get in at those fittings

A good friend will bail you out of jail, but a great friend will ...

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