r and r my hydro cylinders d4

by the 8F designation it appears you have the late style cylinders. You can still get the rebuild parts from Cat but there have been several upgrades....like the chevron packing and shims are no longer used....packing is now a two piece affair, no adjustment required.

OM, any idea of the cost of the rear seals 8F2685?
I nearly fell off my chair when cat gave me a price over here.
Was thinking of having two pistons made up to take more commonly available seals.
I am in the process of changing over to the late type cylinders as the old style keep blowing the seals, which I read is a common problem.

Glum, it sounds as if those parts were manufactured from 24ct gold...

If you can, take the disassembled cylinder to your local hydraulic shop. They'll probably have seals that would work. While you're at it, it's not a bad idea to replace the brass bushings at the same time. Excessive wear on them will allow the piston rod to move up and down and that'll translate into more wear on the seals.

My rods had some deep grooves running length wise and upon inspection at the front of cylinder the packing had let the rod drop until the rod hit the cast iron front cover. It looks like there should be more room there for the packing to do its job. Has anyone milled the opening out recede the the cast cover so the packing is more proud? where are the brass bushings?
greg

You meant the brass eye bushings, thats a good idea,

greg

irnwrkr,
The entire 3F9378 gland is brass and that is your rod bearing support. Packing adjustment is obtained with the shims. No running into cast iron. The gland can be bored and sleeved if severely worn.

Glum,
Sorry I do not know the cost on the late piston rings.
I believe something has been lost on the old style piston seal fit. Even the new Cat seals do not fit right and require about a 0.030 in. teflon backing ring to keep them in the retaining groove.

I thought it was aluminum,the gland has the look and color of aluminum. It is scored pretty good too. How much free play should there be between the rod and gland? maybe I can roll the gland 180 degrees and put the score at the top?
greg

I suppose aluminum would work although I have not seen it used. I'd guess about 0.010 in clearance would be about right but I have no actual specifications.