Ford 555C boom/dipper

[Rich555C]

Hi, I'm new to the site. I did find a post related to my concern and did reply to it but the post is 4 years old and have not received a reply yet so I figured I would ask the question again. I just purchased a Ford 555C in great condition. I am having an issue with the backhoe. I can combine any movements on the hoe at idle or full throttle with full stick movements and everything works except when I was the dipper and the boom together. The boom and dipper work great when used separately. If I move the boom in and then try and move the dipper in, the boom will stop, and the dipper continues to work. If I move the dipper in and try to move the boom in, the boom does not move. I can feather both dipper and boom very lightly at the same time and both will move together. I spoke to someone locally that operated a 555 for years and he said this was not right. He could move both controls at full movement and they both worked together. He also mentioned, and it makes sense, it would take forever to dig something the way it is now. The boom and dipper are the largest cylinders on the tractor. I know the value block for the controls is a segmented design and the oil passes from one to the next. In one side and out the other. The dipper and boom are a couple of segments apart. Did anyone ever figure out what the fix was? Thanks

 

[Dman1981]

Pressure check and a flow meter

 

[K5lwq]

Definitely need to check flow rate. Your backhoe is open center design. The valve stack should have a parallel channel for excess fluid to be available for the next valve. But because the bigger cylinders you are running out of available fluid to work at full capacity. This is why when you feather the valve you can get it to work together.

Possible issues could be filter needs replaced. Also there may be a strainer on this unit that could be clogged. Not sure if it has this or not but I think it does.

Another possibility Is worn pump. But a flow test is definitely in order to start figuring out where to go next. Hope this helps and good luck.

 

[Rich555C]

Thank you for the responses. The hydraulic filter is new. The operator's manual does show an outlet screen under the outlet hose. It's supposed to be services every 1200 hours. The amount of maintenance with this tractor is huge. I'm going to take a guess and say it probably has never been cleaned. I have an operator's manual and parts book but not a service manual, but it looks like it might not be that hard to get to. After the grill is removed, I'm hoping the hydraulic cooler will tip forward out of the way to gain access to the outlet hose. I'm hoping to find a clogged screen verses a weak pump. All other hydraulic functions great.

 

[EddieWalker]

I have a 555E, so I can't say for sure on yours. Do you have a big filter inside your hydraulic tank? On mine, there is a round plate on the side of the tank that you have to remove to get to that filter. The tank has to be drained, which is why it isn't changed very often.

 

[rScotty]

I think that you should hold off on the flowmeter test equipment. They are a couple of thousand dollars, hard to hook up, and I doubt if that info is going to tell you anything new. Very few tractor dealers have a hydraulic flowmeter. Maybe some of the industrial dealers do. I've never seen one in a small shop.

A pressure gauge is a different story. Eventually you ought to geta 5000 psi glycerin- damped pressure gauge and some hardware to mount it at the main input port to the BH valve stack. Sitting there, it allows you to compare one valve against another.
Amazon has portable pressure gauge test kits with multiple fittings for under $100. Or make up your own for half that.

I have a JD310 and never did understand the hydrauics until I studied the service manual - which comes in a set of volumes and is costly but worth it. Recommend you get the original parts and service manuals. Look for used manuals on Ebay. Lots there.

rScotty

 

[rScotty]

SNIP...... The operator's manual does show an outlet screen under the outlet hose. It's supposed to be services every 1200 hours.

The amount of maintenance with this tractor is huge. I'm going to take a guess and say it probably has never been cleaned.

I hear you on huge maintenance. The recommended maintenance on a JD310 would just about take a full time maintenance mechanic. So of course it never gets done.
Ours is a 2006 model with 6000 hrs and I bet a third of the maintenance items have never been touched. It works perfectly.

I have replaced a number of rubber hoses. Always suspect the main suction hose from the sump to the hydraulic pump inlet. Inspect the ends of that hose/pipe for oil wetting which means it is sucking some air. Entrained air degrades a hydraulic system.

Your problem doesn't sound too bad. If that filter doesn't fix it, new possibility would be to look at the auxiliary valves that are associated with your dipper or boom control spool valves. The 555 hydraulics shop manual will have details.

Basically, in a backhoe control valve array, each one of the 4 to 8 control spool valves on that BH control array tends to have several smaller cans bolted to every one of those spool valves. These cans contain each spool valve's own relief valve, drop protection backflow valve, and an anti-cavitation valve for that spool valve's motion. Sometimes those features are combined, but there are stll lots of these nearly identical accessory valves sort of riding shotgun for each control valve spool.
Normally these accessory valves are poppet & spring type, and more or less rebuildable/cleanable. They sometimes get crud caught under the valve face.
If the screen doesn't do it I'd head there next.
But get a shop manual first.
rScotty

 

[Rich555C]

I have a 555E, so I can't say for sure on yours. Do you have a big filter inside your hydraulic tank? On mine, there is a round plate on the side of the tank that you have to remove to get to that filter. The tank has to be drained, which is why it isn't changed very often.

My tank does have to be drained and there is supposed to be a screen inside the inlet hose for the pump or tank outlet hose, same hose. It's right under the tank. I agree with you. It is not easy to get to like the hydraulic filter and probably has never been serviced.

 

[Rich555C]

I think that you should hold off on the flowmeter test equipment. They are a couple of thousand dollars, hard to hook up, and I doubt if that info is going to tell you anything new. Very few tractor dealers have a hydraulic flowmeter. Maybe some of the industrial dealers do. I've never seen one in a small shop.

A pressure gauge is a different story. Eventually you ought to geta 5000 psi glycerin- damped pressure gauge and some hardware to mount it at the main input port to the BH valve stack. Sitting there, it allows you to compare one valve against another.
Amazon has portable pressure gauge test kits with multiple fittings for under $100. Or make up your own for half that.

I have a JD310 and never did understand the hydrauics until I studied the service manual - which comes in a set of volumes and is costly but worth it. Recommend you get the original parts and service manuals. Look for used manuals on Ebay. Lots there.

rScotty

I bought the tractor from the original owner. It's a one owner tractor and I do have the original operator's manual and parts book. I did notice last night that there are quite a few used service manuals online for sale.

I like the idea of building a pressure gauge set up. That will be my last resort if I do not find anything with the screen.

I did dig a crawl space once with a JD 310D extend a hoe. It was a nice tractor and I remember the boom and dipper working simultaneously without any issues.

 

[Rich555C]

Those are all good points. You mentioned oil wetting. Do you basically mean oil leaks around the suction hose? I'm thinking a suction hose leak while running would cause cavitation of the oil and degrade it fast. And then possibly leak while not running. I can glance at mine somewhat through the grill and see a lot of residual dirt and oil mixed. It also could be from spillage from adding to the tank.

The value block assembly is not that bad to access, and I can see those small can shaped covers. Some are on the top and some are on the bottom of the value block. I'll have to look at my carefully. I can see the ones on the bottom collecting dirt over the years and possibly sticking or dirt holding them open causing a pressure loss. I figured they were covering some sort of pressure relief value. I'll check those after the screen.