A friend of mine recently purchased a case 630 and the 3 point hitch would not work so after checking the fluid be saw it was low and topped it off. After that it worked fine, we hooked up the plow made a pass and it wouldn't lift any more so we checked the resevoir and it was empty again so we topped it off and everything worked fine for another pass and then oil started comming out the transmission/rearend breather and gear shift boot. I told him it was probably the lift cylinder leaking but I didn't have time to mess with it yesterday. So he ended up pulling the top cover off and dropped it off with me this morning. From what we can see the lift cylinder piston has a cup at the rear where the rod goes in that pushes the lift arms. The Rod has a o ring on the end but it doesn't really do anything other that sit their becuase the hole in the back of the piston is so much larger. I guess the big problem right now is that I can not push the piston out of the cylinder, is their a secret to it and their appears to be a small hole (about 1/8") in the center of the cup at the back of the piston, I can take pictures but I am not real sure how to post them on here. If any one has any oppinions or ideas I appreciate it,
Thanks,
Denis

Thanks. Some times when a person has a problem a cure comes along and some times you have to ask for help. That is why we stop by here now and then.

Try putting the u-cup in very hot water, not boiling but hot. Then start it over one side and work it around with a small screw driver kinda like putting a tire on a rim. A round one with no sharp edges or points. I installed my completed piston back into the cylinder useing a piston ring compressor and lots of oil. Search this site, this job has been on here several times.

Barry, I read the piston ring compressor trick on here a while back. I filed this in the back of my mind for when I have to do this, if ever. Guess I need to invest in one of these, will need it anyway when I finally do my engine rebuild.

Jim

I finally got it out and found that it does have the u-cup seal and i see what you mean about it takeing 6 guys I could not get the new one on yet is their any helpful secret.
Thanks,
Denis

hope you got the seal on by now ,, Air will push piston out for repair ,, When installing new . Remove large Scraper leather , from that end of piston roll new oring into place with the sharp taper against the oil pressure side... use a ring copressor sleeve or a 4ich hose clamp and thin flashing coil to carefully instal back in bore ...

That is an old style piston. Also its not supposed to have a hole in it, it needs to be replaced. THe new seal set consists of a wide guide ring and what Case call a U Cup seal. Piston and seal set are still available from Case. When you try to put it back in I am told by 630crazy that it takes 2 people and 6 hands to get the U cup seal in the bore so have your friend come back over when you are ready to do this.

My 630 arms hold up for several days. It slowly drops but takes about 2 weeks to go from about 1/2 up to full down with no load.

Jim