Low Hydraulic Pressure

[Turner85]

I only have about 7-800lbs on my remotes and I can’t pick up my grader blade with the 3 point hitch. Installed a used hydraulic pump and the pressure remained the same. I have searched the forum and read past posts. The O-rings on the tube between the pump and cover were good. I shimmed the unloading valve and the pressure is still low. I appear to have the early style valve; I am unable to find a part number for the original or any replacement. Any other ideas?

[mathias1]

Did you check the pressure on the tipping pipe?

[Emiel]

Hi,

What oil do you use and did you check on the intake filter?

I'm not quite sure on the design of the control valve, which one is fitted? Single lever, dual lever or do you have the super major cover?
Can you place some pictures?

rgds

Emiel

[Turner85]

SAE 30. I did clean the filter in the bottom of the differential when I changed the old oil. I have one set of remote hydraulics. I bought a complete unit from a junkyard. I will try and get some pics next time I'm at the farm.

[Turner85]

Sorry for the delay, work has kept me away from the shop. As far as the valve I have style A:



Here is the top of the differential before I added the aux valve

And the finished product before I installed it on the tractor.

The gauge, reads about 700psi with lever depressed


I replaced the spring tonight, added more shims and the pressure stayed the same. I'm about to pull out my hair. Any help would be appreciated

[henk]

Have you checked the inside of the pump?
Two time I had lost of pressure doe to a broken O-ring thats around the butterfly inside the pump. Broke two times because of play on the gear wheels. Simmed the gear wheels and had no trouble so far.

[Turner85]

I havn't looked in either pump, since the pressure stayed the same after I switched them I dismissed that but I'll tear it apart first chance I get
Thanks.

[Emiel]

Hi Turner,

If pressure remains the same when shimming the valve, the pump does not supply more pressure it seems. Open up the pump, and you'll likely find something similar to what Henk found.

Rgds Emiel

[Turner85]

I disassembled the original pump I removed earlier. I could find nothing wrong with it.




Also the diagram on New Holland's part website shows a different pump, looks like a super major pump. Does anyone have a diagram for a Major pump?


I have two friends who are tractor mechanics by trade, unfortunately no one around here knows anything about British Fords. I got some funny looks last time I went to the local dealership

[oehrick]

Have you checked the sides of the two gears and the equivalent rubbing surfaces either end of the housing ? if there are two circular wearmarks each side of where the gears rotate this might be a release/ escape path for the oil under pressure. any detectable gap here is not good news.

A decent hydraulic pump repairer out to be able to rig this up to test pressure and flow characteristics

Meanwhile, if you do not have them already, you can download free copies of the E1A Parts book which covers the main variants and the repair manual in 6 sections from here

http://www.smallholderservices.co.uk/id25.html whuch might assit you

Good luck

[Turner85]

You can see where the gears run, I can feel it with my fingernail. Its not exactly rough but there is a difference
Thanks

[henk]

O-ring at the butterfly seems ok. I advise to put all new o-rings in the pump at assembly.

[Turner85]

Decided to disassemble everything, thought maybe I'd see something I had missed before, when I pulled of the hydraulic valve I found some of the gasket maker had covered this hole.

I doubt that it is the cause of my problem but it did stand out.

Also what is this?



https://dextamatt.imgur.com/all

[Emiel]

Hi,

I'm affraid I can't help you in detail here. Never worked on those valves. To the what's this question, can't identify the part exactly. Give a little more info's.

Otherwise, just clean everything thoroughle. Use liquid gasket very little and assemble very neat. then you should see improvement, or have overlooked something I can't find in the photos.

[oehrick]

It is possible to fit a second valve for say a loader or hedge slasher drive, this may be a port for such a valve so blanked if only one valve fitted ?

[Old Hywel]

If the pressure remained the same after fitting a different pump, then the problem must lie elsewhere.
Can you fit a pressure gauge into the linkage lift tapping? If that showed better pressure, it should narrow your search.

[Turner85]

Finally round up all the parts and pieces to start again. I replaced EVERY o-ring in the pump, plus both o-rings on the pipe coming out of the pump. All the parts came from FORD. First the 3 point will pick up a full grown man now, it wouldn't do that before. But it was too cold to get out of the shop and try to pickup an implement.
I still have 7-800 psi at the remote, I have exactly 800psi at this plug on the right side.


I was able to get 1300 psi on the left (jack tapping plug)


then I shimmed the valve with 2 nickles. I rechecked everything, no change in pressure. But I do feel like I made some progress at least. But not sure why the jack tapping plug has higher pressure. Thoughts?