We have been having problems with the stick cylinder on a cat 385, it worked well up to 4500 hrs after that its been failing repeatedly, we have had it repaired it fails again. Does any one know what would be causing these failures?
In what way has the cylinder been failing?
Started with leakage around the neck gland area, replaced bush and seal, rod failure, then barrel failure, not sure what happened this time i will find out tomorrow. Am told that this is common on these machines, not sure how true it is.
The tube have a tendency to go oval at the end casuing the oring to fail, I think there's a service letter on the topic.
Worink in a high impact application, like rock excavation, will make the cylinder "bounce" up and down, fatigueing the metals, and leading to early failure. Poor operators tend to magnify the chances of this happening.
Yep, gravity and inertia tends to have an effect on a big heavy rod like that on a 385 when it's extended.
If you're going to have 385's around cylinder problems are something you're going to have to get used to. I have worked around and run lots of 385's and they all had cylinder problems. Hire a good mechanic, your going to need it with one of those around.
There was a service letter for the rods breaking at the piston on B and early C models. A new rod was replaced on the stick cylinder weather or not it had failed.
We stripped and checked the cylinder today. Looks like might have been a bit a contamination from the previous failure, maybe a good lesson for anyone with this type of failure make sure you clean your system or you might experience a very expensive repeat failure.
If i remember correct, there is a scheduled overhaul every 4000h on theese sylinders. That might be a local "rule" here in Norway..(leasons learned maybee...) But still, if it starts to leak, overhaul! There is very little space between the piston and the tube. When the gasket wears out, the piston quickly starts to shave off the sylinderwall. And there is very high wear on the gaskets because of the pressure on the gasket sideways. Same problem on the bucket sylinder on 988H..
Might be a good idea to include an ISO Cleanliness Code test in your oil sampling, assuming you do SOS sampling. You should be aiming for ISO 18/15 or better. If the dealer does the repair for you insist that they bring a portable oil recovery unit and a particle counter to site with them and show you what the system cleanliness is before you finally sign off on the job. Also make sure whoever is doing the repair does a full system check & clean out. Not quick or cheap but prevents things like this. Whereabouts in Zambia are you ..?
it seem tube problems, please try to retube or change cylinder tube. may be any defect occured to the tube, ovals, scratchet, and pitted, please check sutface and hole inside diameter before.
I am no expert, but could your problem be misalignment?