loader Cylinder rebuild

I was thinking while doing the clutch on this Kubota I should do a few other repairs on it. The lift cylinders on the loader will leak down owernight and I would like to put new seals in it while it's apart as well as a few new hoses. The implement cylinders are okay yet. I have a parts diagram here and was wondering what seals would all be needed to do the job. Any body here have any experience with these ALO cylinders. Anything you can share would be appreciated. Thanks

Looks like you need part# 5036155. the complete seal kit.

I worked for Case for years , and every cyl has a kit, or if your feeling lucky , individual seals. We always replaced everthing with the kit.....

the seal causing the leak down would be # 13, piston seal. but a mensioned seals come in a kit to replace everything.
but your problem may be in the hyd. block on tractor if both cyl's are dropping.

Since the cylinders are connected together, it only needs one to leak for both of them to drop. Cylinder seals leaking is the problem about 9 times out of 10. If you have the cylinders apart replace all the seals at the same time. Make sure to put a little oil, grease or vaseline on the seals when you put the cylinders back together. This will help prevent the seals from getting damaged when putting the cylinders back together.

(quoted from post at 11:02:12 01/29/12) Since the cylinders are connected together, it only needs one to leak for both of them to drop. Cylinder seals leaking is the problem about 9 times out of 10. If you have the cylinders apart replace all the seals at the same time. Make sure to put a little oil, grease or vaseline on the seals when you put the cylinders back together. This will help prevent the seals from getting damaged when putting the cylinders back together.

Click to expand...

Does it leak clear down?? if the valve is good the cylinders will only leak down far enough to allow the pressure to equalize on each side of the cylinder then the cylinder will stop and in effect becomes a displacement cylinder with the rod area on the bottom of the cylinder doing the supporting. The reason this happens is that the return from the top of the cylinder has no return because the spool is closed so pressure builds up in each port as the piston area on the bottom has more displacement than the rod end as the rod end of the cylinder contains the rod which causes it to hold less oil than the bottom. Kinda complex and I hope I have not added to the confusion but I have made a life of diagnosing these problems ( 50 yrs in June). If your loader is equipped with disconnects you could support the bucket, uncouple your disconnects and remove the support. With the valve out of the system you could remove the coupler from the rod eye end of the cylinder and see if you get leakdown and oil leakage from the open hose as that would allow oil seeping past the packing a low pressure place to go.

Isolating a leaky cylinder is another issue as if one is leaking internally it will allow both to leak down on a tandem cylinder system. mEl

Very good explanation, a whole lot of people do
not understand that the rod displaces fluid and if
both outlets of cyl are sealed, weather it is the valve or
couplers, that fluid has no place to go and cyl
does not move. Also, the pressure on both side in
cyl greatly increases and will cause a valve to
leak that will hold normal pressures ok. I have
unhooked know bad cylinders and allowed them to
sit with a load on them just to prove to people
they will not go down if you have both ends
plugged. Often it is easy to tell if a cyl is at
fault just by raising the load a little, then
feeling of the couplers when they are still hooked
up. The load holding coupler will and should be
under pressure and tight in mating coupler and the
return side coupler should be free. If the cyls
are such that they hold a load up on an extending
rod situation like a lot of bucket cyls on loaders
then different rules apply.