I recently acquired a CAT E120B excavator and realized I had a leaking piston. Would like to know what it would cost to bring it to a shop for repair, and secondly, what special tools I would need to repack the piston myself. I had not previously owned heavy equipment. :beatsme Thanks
By leaking piston i am going to assume you diagnosed this based on the cylinder drifting on its own when no control levers are actuated. To repair this is quite easy, you just need to undo the head bolts, disconnect the chrome rod of the cylinder where it is pinned, support everything (usually with a small jib crane) and slide it out. R & R seals and wear band and slip it back in. Just remember to release all hyd pressure before disconnecting any lines. Now if your head seals are leaking this will be identifiable visually with oil running down the chrome of the rod and if it is bad enough dripping on the ground, this requires the same dissassembly but you then have to remove the nut holding the piston on and this is done up to a few thousand lb ft which requires in most cases a trip to a dealer with a ram bench to undo. To do a full reseal it should be a 4-5 hour job for 1 ram and depends on the rates for where you have it done for a total cost but $500 + parts i would think reasonable.
Gavin84w, Thank you for your response. After reading your response the problem is in the head seals. I have read some of the other threads about this same problem and it seems that the nut is the hard thing to crack. Basically, do you recommend that I take it to someone with a bench to break the nut because of the amount of ft lbs. of torque necessary to reseal, or could I do it myself ? Please Advise. Thanks Derrick
OK, now thats sorted lets move on!!! With regular blade, ripper cylinders etc i have oxy cut say a piece of 1 inch thick plate with a hex just oversize of the nut with about 12 - 18 inch of length so as to use it as a flogging spanner, then set the rod on the ground and put timbers on each side oy the rods eye and get another machine or something very heavy and sit on it. The rod should pretty well be parallel to the ground now and have the head slid right back up against the piston then set up the flogging spanner and get busy with the 14lb hammer!! Trouble is i seem to remember excavator cylinders are done up to a very high torque on the nut so with your modest mechanical skills i think taking it to a ram bench will be the go.
Thanks again I figured as much....
Sometimes I leave the barrel end of the cylinder on the machine,this helps to act as a vice when I break the head nut loose.Then loosen the lines and pull the rod & head assembly.A 1" drive socket set should work fine for breaking the nut on the rod.I have also put some heat on the nut .I hold the rod by putting a 3' shaft though the eyelet and wedging the end of the 3' shaft between the track frame & rails .This puts the cylinder rod parallel with the tracks on the ground.put some wood cribbing down to keep the head out of the dirt.1" drive breaker bar & cheater pipe usualy get the job done.Intstall new seals& o-rings ,lube them with oil and reverse the procedure.
strzempk83, Good luck with your cylinder rebuild, keep us posted. I also recently got an E120B, Mine needs the stick cylinder rebuilt. I'll probably try to do it myself. Just replaced tracks, sprockets, bottom rollers, and rebuilt swivel joint. It's always something !!!!
Welcome Will 756.If you can replace tracks,sprockets,rollers,& swivel joint the stick cylinder will be an easy task.Good luck with it.
Thats sure is the truth... Thanks for everyones input.
Oh Will 765 where did you get your parts if you dont mind me asking?
strzempk 83, sprockets and rollers I got from Heavyquip.com out of florida. The track (used chains with pads) I got from a local outfit, Wengers equipm ent salvage, Myerstown, PA. Other parts from the dealer. Where in Vermont are you located?
Located in the North east Near St. Johnsbury. How hard was the Swivel Joint to do?