A project I want to tackle soon is the re-sealing of my CAT 225 bucket & boom cylinders. I have re-sealed many cylinders in the past for my other equipment, but nothing with more than ~1100 ft-lb required for the piston nut torque. These CAT 225 cylinders require around 2600-2900 ft-lbs to properly torque the piston nut. I do not have a cylinder repair bench of any kind. In the past I have borrowed 600 ft-lb torque wrenches and torque multipliers to get jobs done, but I have no source for any equipment that will get me up to the ~3000 ft-lbs. For those with experience, at what point is a cylinder too large to be re-sealing without a cylinder repair bench and doing manually with hand tools and long pipes?
Question: Do you have a hydraulic shop near you with the capability to remove/reinstall the piston nut if you took the rod & piston assembly to them.? If the spec is up to 2900 then you can bank on it taking significantly more than that to crack the nut off when removing it. If you plan on re-using the nut some Loctite might be advisable because the nylon insert will probably be hard by now.
My local Cat dealer was getting $75 to take the nut off and same to assemble. They rarely use their cylinder bench though as they outsource most rebuilds so that price might be high or low. Not sure. Depending on the bore of the cylinder there is also a fair bit of force just to move the rod in the bore, especially with new seals. Had a 7” bore off the Volvo and even with the used seals I had to put a winch on it to get it out. No way I was going to get it reassembled and risk wrecking a $400 seal kit. Ended up outsourcing the whole job as a rechrome was also needed.
When I had the stick cylinder re-sealed by my local CAT dealer ~10 years ago, I just dropped it off and picked it back up, it was like $900, hoping to do these myself. That CAT dealer has since moved much farther away, and not sure they would have wanted to bother with just a nut torque job. Closest shop I have to the machine is a New Holland dealer, however every time I ask their service dept for some type of help like this they just brush me off, they no longer have the tools, they just outsource stuff like large cylinders and track pins etc... And yes, I was wondering about the force required to install the piston & new seals. I have other machines I could use to aid in the rebuild. I was thinking I could make some type of jig and a bottle jack to break the piston nut. I'm pretty confident I could break down the cylinder, the re-assembly is I guess where I'd be looking for advice/tips. I have done re-seal jobs where I have re-used the nyloc nut with loctite, or have purchased new nuts. I usually figure that out after I disassemble and inspect the nut locking element.
I see you are in Lockport. I have used and highly recommend Fluid Power Service in Lancaster. Looks like about 30 minutes away. They did the cylinder I mentioned and the work was fast and they got the details right. Price was reasonable. Even replaced the zerks and gave me new bolts for the flange fittings. Thing I liked was they do everything in house including the chrome and machine work.
That's interesting, thanks. I have another machine that needs the rods re-chromed.
If you have enough heavy iron around its easy cut a nice wrench out of plate Much safer than pulling on pipes pin it to one machine and use another to work the wrench