Hydraulic control valve allis chalmers 185

[Ronnie]

I recently acquired a 1974 allis chalmers 185. It has a nice westendorf loader on it that is jerky and slow to operate sometimes. It's got some leaks and the fluid is milky, maybe it's sucking air? So I have been working on the leaks and after I get the leaks fixed I will change the fluid and filter. My question is the adjustment screws on the back of the control valve. I was messing with them and  turned all the way in, what are these screws actually for? I have also decided that this 75hp tractor will lift a couple of tons but its a pain in the backside working around the sawmill. It's cumbersome and I have had it stuck in the mud 3 times. I wish now I would have spent a little more and gotten a skid steer or a 4wd tractor. I think once I get the hydraulics fixed I will sell her and get something better. Any suggestions on hydraulics and something to replace it with would be awesome.

[Al_Smith]

I'm not familiar with the machine but generally speaking milky fluid indicates water in the system .

Some control valves have pressure reliefs built into them which I assume those screws were .Tightening them puts more pressure on the relief valve spring which would raise the system pressure .

Jerkiness could be air in the lines or cavitating the pump because of lack of fluid .

[Okrafarmer]

I can't tell you much about the hydraulics, except, if you sell it, you will not get a whole lot of money if the hydraulics aren't working right. I hope your pump isn't damaged. If you get them fixed and still want to use it, it may do better with a good counterweight on the back. Not get stuck as much.

[OntarioAl]

Ronnie
1/ Milky fluid is an indicator of water in the system. Draining the hydraulic tank and changing the filter will get most but not all the water. You would need to drain all the lines and cylinders to get it all.
2/ It is jerky because it is low on hydraulic fluid
3/ If I were you I would back off the adjustment screws to as close to the position that you found them in.
They are port relief valves they protect the system from mechanically generated pressure spikes (rapidly lowering a heavy load and suddenly stopping) You need a 0 to 3000 psi gauge and the manufacturers specs to properly reset the port reliefs.
You have discovered that a 2 wheel drive tractor with a load  being carried becomes difficult and sometimes frustrating to manuvere (been there done that). As Okrafarmer suggests a good counter weigh will help, loaded tires and tire chains could be other options.
Hope this helps
Al

[Al_Smith]

Well another thing I forgot to mention .You could get cavitation which is running the pump without a full head of intake  oil by the type filter it uses .

Some have a return oil filter which filters the oil on the essentually low pressure return to the tank .Some have a suction line filter that catch the oil after it comes from the tank .If the later type  is plugged up it will starve the pump .

[snowstorm]

if the oil is white it has water in it. water dose not flow thru the filer well. therefore the pump cavitates the loader is jerky it needs to be fixed or it wont be fixable

[DDDfarmer]

I have a AC 185 no loader,  PTO 74 hp drawbar 63 hp.  not heavy enough or geared right to be a great farm tractor.  I would start watching your transmision oil level and the hydraulic levels.  Watching mine the tranny level will climb as the hydraulic goes down and vice-versa,  there is a seal gone in there someplace.  There is somewhere that water does get into the system, as i can always drain some water and the steering freezes up in the winter. 

When the hydraulic system gets to the low side the hydraulics get jerky real fast, and it does not need to be really low.

To help with the getting stuck you need a different tractor.

Load up the rear tires with calcium to the max,  and if you think that you will be getting into some mud put it into 3rd high range open it up and go.  just wont work with a loader.

[Okrafarmer]

I worked on a farm up in Maine that had a much bigger AC tractor, model 8050. It was another one of those that lost fluid, in this case, from the transmission, to the hydraulics. Must be an AC thing. AC are not really my favorite brand. And yes, I have had two of them myself, a model B and a model CA. My grandfather and uncle had another CA. Practically everyone I have known with AC's has had more trouble with them than seems right. Too bad, some of them look really cool.......