1942 D47J Cylinder packing? 5" piston

I wonder if these SKF single direction seals would hold up -

https://www.skf.com/us/products/industrial-seals/hydraulic-seals/piston-seals/single-acting-piston-seals/unp-profile-data

the seals are available as we had them replaced when we did up our rams on our 6u

try a hydraulics shop. there is probably a generic seal that will fit. i cant remember if we used genuine seals or not.
my parts book for the type 44 hydraulic unit lists for a 5 1/4 bore x 24 stroke 5f3383 as the piston packing and 4f8420 as the vee packing 1b936(1st and 2nd type ram) and 1k6982 for the third style of ram i seem to remember we got genuine parts.

if you clean up that part number on the casting someone may have the parts diagram you need or perhaps you local dealer can find it from that part number

ive been all over the net and even went to a local shop who were useless. spent 3 hours on calls all over the palce. Cats website has no seal with those specs and some of their seals are missing data so it might be there.

My cylinder bore is 4.750 and piston seal OD is 3.750- 5.16 width. emailed a bunch of places. I dont just come here crying at the first go- ive literally been at it for 3 days.

Ill try hercules thanks- my piston is a 3 piece worst case i can machine new end plates to accommodate cat seal. They do list one for a 4.750 bore at least-

and fwiw my seals are called buffer seals and used as the primary seal in the piston - very confusing but yes thats how it is.

On a D4 I was working on a couple years ago I had to machine the gland housings to fit a set of different chevrons and the wiper seal. One of them was so corroded from coal dust from years of neglect in a coal mine, I had to set it up in the mill and keep boring it out till I got the sleeve that pushed on the chevrons out. Don't know exactly what seals we used because my son got them from his work that has a hydraulic division that rebuilds all sizes of cylinders for the mines and steel mills. The piston seals if I remember correctly were good to re-use and are probably a later style because it has 3 rings.
I can check and see if he remembers any numbers we used. I might be able to post some pictures once I figure out how to load them from my phone.

I have been told Hercules manufactured seals for Caterpillar for many years and possibly stil ldo. Pretty safe bet Cat never ever made their own. Worst case it would not be hard to make a new piston once you have the correct dimensions for the seal groves. best of luck WF

Hi, CamaroMan.
When chasing parts for older Cats, it is often necessary for the parts people to go to a separate section of their parts catalogue called "Classic Caterpillar". Try asking your local dealer to check that out on their parts computer.

Just my 0.02.