Ford 555 hydraulics stopped

[Tek]

have a ford 555 and all the sudden all the hydraulics quit...the bucket may lift 3 inches if you baby it alot. I have took out all the relief valves on the hoe and 2 on the bucket..all to no avail. Checked the pump and it seems to be pumping good..it emptied the resevoir into a 5 gallon bucket in short order. Fluid is clear, no air bubbles and is full. Also put in a new filter.
Need help.
Thanks,
Tek

 

[DGODGR]

How did you check the pump? Which 555 (pre-letter designation, A, B, C, D , E, or ?) are we talking about anyway? Which bucket is lifting 3"? Any strange noises when activating the hydraulics? When did you last replace the filter? Does the engine lug when you try to operate it?

 

[Tek]

Its a 78 model..I dont know what letter.. it doesnt have any on the side decal. I pumped the oil out the little plug on the filter. It shot out with good pressure in the 5 gal bucket. The front bucket is the one lifting. No strange noises. We dug a septic tank hole and field then started on another project for some drain lines and it just quit cold turkey. One time while we were digging the septic tank part it was just idling there and I got back in and it wouldn't do anything...I shut off the machine and waited a little then started it up and all was well again. I was able to do the whole drain field 12x30 4ft deep then after that it quit. Every thing sounded normal and worked good till then. I barrowed this machine and the owner said that he had it do this on him after he was carring a very huge rock bigger than he should have. He took the top of the relief valves apart on the hoe then it started working.
No the engine did not lug..it runs fine. We used a skidsteer to lift up the hoe and down riggers to get it to the shop to work on it.

 

[DGODGR]

I would suspect the pump. I recommend that you find out what pressures are required and check pressure and flow at the pump. Your "bucket test" is probably not very reliable. I am trying to figure out how it works, at all, without the relief valves installed. I would think that, without the relief valves, all pressurized hydraulic oil would just return to tank, unrestricted, leaving nothing to power the implements.

 

[Tek]

First we installed all the relief valves after looking for broken springs or o rings. Then we reinstalled them...so the everything is together and ready to work. We took the pump off and apart..didnt see anything out of the ordinary. It is a gear pump. We discussed the posibility of having a pressure guage to see the pressures, but was wore out after a whole day of undoing a doing to no avail. Where and how would I check the pressures ? Thanks

 

[oarwhat]

Tek we had a 555 with a similar problem. Hydraulics slowed way down. Something in the hydraulic tank fell down and blocked the the intake line to the pump. This was 20 years ago so the details are fuzzy can't remember if it was a baffle or???

 

[Tek]

I can watch the oil circulate by looking in the hydraulic tank..it moves at a good rate. Thanks for the suggestion though.

 

[Tek]

How and where do you check the hydraulic oil pressure.
Thanks tek

 

[DGODGR]

I don't think they had test ports on those Fords. I'm not possitive but I would think a flow/pressure meter on the output side of the pump. This is not an "everyday" tool so you may have to employ a mechanic for this.

 

[Check Break]

have a ford 555 and all the sudden all the hydraulics quit...the bucket may lift 3 inches if you baby it alot. I have took out all the relief valves on the hoe and 2 on the bucket..all to no avail. Checked the pump and it seems to be pumping good..it emptied the resevoir into a 5 gallon bucket in short order. Fluid is clear, no air bubbles and is full. Also put in a new filter.
Need help.
Thanks,
Tek

Sounds like you have a straight 555 and it takes forever for your loader to raise up 3 inches. You should hear a load on your pump when the engine is running which goes away when you move a control on the backhoe valve body. There is a relief valve for the front loader under the ROPS deck, right hand side on the A model; I don't remember whether that was a change from the early 555. The relief valve comes out the top of the valve body. There should be a tiny particle causing the valve to stick.
If you are sure you have the relief valve handled, another cause for that kind of problem is one of the loader lift cylinders is bypassing. You can crack one of the lines to check for fluid under a high rate of flow when there should be return oil only in the line. Hope this helps.

 

[maddogoffroad]

Sounds like you have a straight 555 and it takes forever for your loader to raise up 3 inches. You should hear a load on your pump when the engine is running which goes away when you move a control on the backhoe valve body. There is a relief valve for the front loader under the ROPS deck, right hand side on the A model; I don't remember whether that was a change from the early 555. The relief valve comes out the top of the valve body. There should be a tiny particle causing the valve to stick.
If you are sure you have the relief valve handled, another cause for that kind of problem is one of the loader lift cylinders is bypassing. You can crack one of the lines to check for fluid under a high rate of flow when there should be return oil only in the line. Hope this helps.

I have the same problem with my 555A the hydrolic just stop working. Took the pump out and it slitly show some wear, not enought to stop everything as it was a mechanical pump. which was my bad, the pump will lift my bucket up if i rev the engine to max but nothing on the hoe side. But before i put the new pump in i took the two section slice/knife releif valve and the main releif valve. Be very carrefull when you screw the releif valve not to change ANY of the setting you had before. I didn't and i ended up having the pressure building up that it blowing up the back of one of the slice/knife. now i'm looking for one of the slice if any one of you have one in your shop somewhere.

Thanks

Chris

 

[maddogoffroad]

Can i change that control valve set up, with two 4way joystick? or one of these items at Princess Auto.

http://www.princessauto.com/pal/category/1300-370-464-748-363/Manual-Dcv?page=1

BM70 4-Spool Directional Control Valve
BM40 2-Spool Joystick Directional Control Valve