# Ford 555 tractor/hoe hydraulic problems



## 55Keith (Nov 17, 2012)

Tractor hoe was being operated and job was nearing completion. When operator went to raise the right hand hoe support, it moved about half way and stopped. The hydraulics have not worked since. They replaced the pump, filter and pressure control valve for the hoe hydraulic block. Stilll nothing has worked. Would appreciate any suppestions. Also if someone ot there has a drawing of the check valve, please send to me. Thanks:dazed:


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## sixbales (May 18, 2011)

Your unloader valve may be stuck open, allowing fluid to freely circulate, with little or no pressure. Which probably means the RH hoe support gave a pressure surge while raising it, causing the unloader valve to stick open. 

See item #23 on the attached diagram.


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## 55Keith (Nov 17, 2012)

The tractor that I have is a 1980 model. This may have been before the surge valve was installed. Every thing that I have found so for leads to the reservoir being plugged or the new prv is not working properly. I appreciate the support and more drawings or sketches would be appreciated. Thanks


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## Viper (Nov 28, 2012)

I also have a '78 model 555 and after servicing the machine the hydraulics are weak, any ideas on what may have happened?


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## sixbales (May 18, 2011)

Keith,
For a diagram that you can print out, go to the "Official New Holland Online Parts Store" on the internet:
- Click on "find parts by model"
- Enter 555 as your model number.
- Click on the little magnifying glass to do a search.
- Click on 3 cyl Tractor, loader, backhoe (10/78-10/88).
- Click on Hydraulics Systems, hydraulic pump, or whatever else you want to study.. 

You will probably need to get a shop/service/repair manual for your tractor for troubleshooting guidance and procedures you need. Go to tractor parts/supply stores, or look on ebay.

Viper - Please start a new thread.


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## sixbales (May 18, 2011)

QUOTE - "Every thing that I have found so for leads to the reservoir being plugged or the new prv is not working properly."

"The most frequently overlooked items are suction screens & filters. They get plugged so badly that the pump sucks air through connections. Aerated hydraulic fluid."

Does your hydraulic fluid have air bubbles entrained in it when it is operating? If so, please refer to Harry's comments to Viper on a similar 555 problem. You may have plugged suction screens/filters.


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