420S hydraulic problems

Case1950

Member
My 1957 420S 3 point is acting strange. The 3 point will not lift up much and is very weak. When selected down it shoots hyd fluid out of the fill. I just took the pump off and everything looks good.

Any suggestions,

Thanks
Case1950
 
Run it and look at the hydraulic oil. IF it is foamy looking , like I think it will be. You have a valve leaking on the high pressure side. So the lift will not lift and the oil gets foamed up and runs out the fill hole. If it is you will have to take the lift controls valves apart to see what is wrong.

I have not had one of them apart in 25 years or more. So I can not tell you off the top of my head how/what to do get it apart. I worked on a fair amount of these back in the late 1980s as guys started collecting them and wanted everything to work.
 
You are right, the oil is foamed up. I have a shop manual hopefully I?ll figure out how to take the valves out when I get home.

Thanks for the quick reply
 
Make sure you use NON DETERGENT engine oil in it. Detergent oil is the cause of many problems with these. One reason to use engine oil is because if you have a seal leak in the pump, the oil ends up in the crankcase. You will know if that is happening when the oil level keeps getting higher for no apparent reason.

Sometimes, a good flush with kerosene helps, but I won't recommend that even though I have resort to it on occasion.

CPeter
 
Foamy oil in a Dubuque and poor lift function can usually be cured by getting rid of the oil that's in there and replacing it with 20wt or 30 wt NON DETERGENT motor oil.
Foam is air and it's usually getting in there at the joints on the large suction line. Each joint has a rubber seal that you may be able to tighten up or you may need to
replace. Seems like the seals are about $8 each at Deere. JMO
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top