Would you expect port reliefs on the blade cylinders?? Vice grips arent going to be any different in that regard. Not to mention pinching hydraulic hoses is not good for their well being.
There are relief valves on everything either sharing a main or individual ones on the circuits. Even my old backhoe attachment had reliefs on everything. Henros idea of adding a check valve bypasses that safety. Yeah the vice grip idea was a joke and would damage the hoses but a check valve will blow them anyway so whats the big deal? Also without solving the internal leak problem, extra heat is being generated.
The cost will likely be less than $150. And you are missing the point related to the time savings and cost involved in trying to repair the issue back to factory specs. That is significant, even assuming I could do it.
Sounds like you already have all the answers Henro but for those future readers with a mini ex and a blade issue I would reccomend reading what others have encountered with this same issue and excavator hydraulic systems in general, figure out the problem before modifying the system. Could be dangerous, could be costly.
I have pretty much reached the conclusion that the rotary joint is very likely the cause. The reason being that there is a change valve that allows the dozer control valve to work the track width cylinder OR the blade cylinder. Problem is nearly exactly the same with the change valve in either position.
rebuilding it is easy and cheap, just a bunch of seals. The issue is its in the bowels of the machine and lots of hoses going in and out so messy to do.
I understand. Unfortunately for reasons including lack of energy, and lack of a suitable place to do it, plus other things that are more important, I can't attempt that kind of repair...tough sometimes when a couple gets old...was going to say LOL but I don't think that is the case for us anymore...insert frown here...
True. But those things are much harder to diagnose versus disconnecting a hose and looking for fluid flow.
This is TOTALLY wrong. I don't know how many times I have seen fluid bypass a in a cylinder. Cylinder position has little to do with this unless the internal cylinder wall is scarred in a specific area. If you worked in heavy industrial maintenance, you would see this often.
Actually if think about it, it is totally right. At least in the context Dan was referring to.
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