How long should hydraulic seals last?
I have a bradco 3265 3-point backhoe. Had it about 7-8 years, probably less than 300 hours with it actually mounted. Relatively light use, a couple of long trenches, planting some trees etc.
I just had the 3rd cylinder rebuilt, and the fourth is on its way... for the stabilizer leg no less which should be pretty low wear.
This on top of the
boom that falls too quick, can't say I would recommend a bradco, what a piece of crap.
Sam, I don't have any real good answers, but it sounds like you are also wanting to know whether what you are seeing is normal or not. I can compare to what I've seen if that will help.
BTW, you say that the cylinders need rebuilding but I missedwhy? What is wrong with them? Falling too fast could be internal to the cylinder but is usually the control valve. I wish I could tell you how to tell the difference, but I've never figured it out. I tend to believe that for a cylinder to fail internally so it would pretty much have to be defective from the beginning - but I think that as control valves age their check valves tend to leak. In my experience it is rare for a cylinder to leak where the extension rod moves in and out unless it has lots of damage there.
As to how long cylinders last, I've only ever had two show a problem. One was on our new Kubota when a cylinder just locked up & wouldn't retract. Warranty replaced it. I suspect it was assembled improperly inside.
The other was the JD310 backhoe main boom cylinder which started to squeak @ 6000 hrs. Disassembly showed it needed new internal O rings. The old ones were packed tight with a real fine particle muddy dust - most likely dust from the clay dust in the air. That lind of dust is common to some western dryland wheat fields.
So far I've never had a cylinder that leaked at the rod cap - even though some of my equipment is pretty old. It used to be common for all the better quality loader cylinders to have threaded end caps with adjustable packing to keep dirt away from the rod seal. That extra dirt seal was a nice touch and should have made the seals last much longer, but my experience is that cylinder rod seals last a surprisingly long time anyway - decades for sure. The few I've looked at had a wiper seal and an oil seal inside that. Not surprising that they last. A few times a season I wipe the mud off of the cylinder rods with an oil-soaked rag and inspect them for dings which get smoothed with a pocket stone.
When an implement leaks down overnight, that might be in the control valve or the cylinder either one. Like I said, I'm not sure how to tell which one is causing the problem.
The Kubota isn't perfect; at 1000 hrs my loader will fall down and the backhoe bucket will eventually unfold toward the ground if I leave them up. But it takes several days for the loader to move perceptively down and several weeks for the hoe bucket. Leakdown must have something to do with wear because when it was brand new neither one would leakdown at all.
About control valves, I didn't know that loader/backhoe control valves had such a range of quality until we got the Kubota. It has control valves that are just better than any other I've ever used on any machine. Light touch, accurate metering, smooth predictable multifunction, no leakdown. Really Nice.
There's a local hydraulic shop that serves the ag trade & will make good quality custom cylinders for same or less than the cost of new ones. Better prices on hoses and cylinder rebuilds than the dealer, too.
Good luck,
rScotty
