Rebuild CAT 225 bucket cylinder in the field?

Take it to a hydraulic shop and get it done on a ram bench, you might get the nut off the piston, you will never get it tightened to the right torque and a loose nut could cost thousands in damage elsewhere.

I had a 225 stick cylinder fully resealed (piston, gland etc) by a CAT dealer about 6 years ago, it was ~$800. I didn't like how much it cost, as I usually do all of my own repair work. However, I just didn't have the tools to be able to handle such a job. It's definitely worth having someone with the correct equipment/experience do the job IMO.

if they have to cut the nut off make sure you buy a new CAT nut. you can get lucky but i see non CAT nut's fale you will get to say 2000 and think where all most there hit 2200 then it will yield and you got to start over as some of CAT fastener are made to a higher stander may look the same but there not.

I too attempted the, "I'll do it my self" save some $$$, boy was I wrong, Take it to a Hyd. shop.

After doing many types of hydraulic cylinders while working at a Cat Dealer, I second every ones call for having it done at a professional shop. Some of them can be a real bugger sometimes.

I guess I went against the grain and took it apart. We went in with guns blazing and it was a pretty simple deal. Machined a custom ultra heavy duty wrench for the job from 1" plate, heat treated, and designed to handle about 15,000ft/lb.

It was just too easy. We will run some calcs to dial in the assembly torque and just hope we can get the piston back in with reasonable force. Plan to just remove the barrel and set vertical so we can lower the rod in nice and easy.

The nice & easy part will be over as soon as that new piston packing starts into the bore...About a 3" cylinder will make you beat yourself black in the face to get in...why real hydraulic shops have ram benches...
Not sayin' you can't do it, but good luck...

the rod may not have enough weight to enter the barrel in the vertical position. we used to have the cylidner mounted relatively horizontal in something that wouldn't move. then suspend the rod by choking with a nylon sling and have it situated in line with the barrel. then we put tension on the sling towards the barrel while maintaining the rod in line with the barrel. lots of lube on the sealing rings of the piston and the barrel, vaseline works, as does hydraulic oil. then if we couldn't get it to work its way in by wiggling it around by hand, we would resort to giving it a huge smack with a bfh usually we used a deadblow or brass hammer to prevent damaging the rod end eye or bushing. once the piston starts in the bore the guide should really slide in by hand. you can do the calculation to use hydraulic cylinder to torque the nut if you know the size of the cylinder to calculate the amount of force at a certain pressure. if you know the force output at a certain pressure, you can calculate the length of lever arm you need on your wrench. ie if you need 26000 foot pounds, and you have a 24 inch lever, you would need to apply 13000 lbs of force to the lever to achieve your spec. if you have an average farm tractor that runs between 2500 and 3000 lbs of hydraulic pressure, you would need to factor that into your force. if the tractor output was exactly 2500 psi, you would need the surface area of the piston of the cylinder attached to your wrench to be 5.2 inches square. if you have a portapower that the guage reads in tons of force, you would need 6.5 tons of force (1 ton of force = 2000lbs.) hope this helps.