Hi all, brand new to the forum after doing some research on this site, and brand new to tractors, backhoes, and hydraulics. So please excuse any ignorance, I'm trying to correct it! I have a ford 4500 backhoe, diesel. I replaced a hydraulic hose that burst, that I believe was hooked to the bucket or dipper. Now, I can only curl the bucket and dipper inward. I can extend thr dipper out about half way and then it stops. The engine or some other device behind me starts making a struggling noise. When I try to move the bucket and dipper at the same time, then the dipper extends all the way. I can also get the bucket to uncurl while pressing the lever for the dipper at the same time. From everything I've seen online, this means a check valve is dirty. Is that right? If so, my next problem is this: there are no check valves on the valve block anywhere. There are some big valves that I thought were check valves but maybe they were anti cavitation or something else. I still haven't managed to get the others off. The internet is saying that my valve block must have internal check valves and I'll need to take the whole thing off and clean it. At that point, I'd rather give up on the machine. Am I missing something obvious that you experts know? Attached pictures are the two big valves I did clean. The two shiny hoses are the ones I replaced.
First off, sounds like you’re low on hydraulic fluid. Where the new hose is to the manifold, was there another fitting, on the old hose. How possible is it that junk got in the system changing hoses?
Very possible! I was low and added about 7 or 8 gallons. The fluid that was in there was milky brown and looks very old. Also, I found a schematic that shows these middle nuts may be the check valves. I'm going to look for a socket and try this weekend to open them up. What do you think the odds are the check valve is just dirty? Is that a common problem?
I would make sure all cylinders are bled and have good fluid in the system before messing with the valve block. Then I would get a gauge or 2 and start checking pressures if possible, that is usually the process, when diagnosing any hydraulic problem. Unless you know trash entered the system and where.