Do Tractor Hydraulics get Weaker When Warmed Up

[Xfaxman]

Do Tractor hydraulics get weaker the tractor is warm?

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I changed the hydraulic fluid, filter and (should have said cleaned) suction screen to see that helped, but still acts the same. I just run generic hydraulic fluid from TSC.

What hydraulic fluid does the manufacturer specify?
If the TSC fluid is too thin, that would cause your problem.

 

[rScotty]

Could also be pump getting worn after 50 years. To determine exact cause would require performing mulitiple tests to eliminate or identify the cause or causes.

first one would be simple pressure test

Operators and manufacturers both seem reluctant to put a pressure guage in the hydraulic line. I have no idea why not. It costs nearly nothing to do and tells you a lot about the hydraulics.
I plumb mine into a T fitting in the pressure line to the FEL control. It's handy, easy to see, and cost about $20 for gauge and fittings.

 

[dieselscout80]

I am thinking that testing with a gauge is the next step.

I wonder if permanent mounting a gauge would be worth it.

 

[rScotty]

There is usually an access to the high pressure hydraulics somewhere specifically for attaching a gauge. It is often a plug in the casting either by the high pressure pump or back at by the 3pt hitch housing. Just remove that plug and screw in a 5000 psi pressure gauge. You can leave the gauge there, although depending on the type of gauge some handle sub-zero temperatures better than others.
Alternatively you can put a T in one of the loader lines where the line connects to the loader control valve.

 

[Xfaxman]

I am thinking that testing with a gauge is the next step.

I wonder if permanent mounting a gauge would be worth it.

I did on the put-together, right in the valve:

Can see it from the seat.

 

[Doughknob]

BINGO for the guys saying "valve." OP says it goes up slow but will stay up once there. Problem seems to be "when going up" and that is when the valve is open! When control valve closed, rockshaft cylinder stays put = internal valve leakage/wear. as others said......
I have had the rear remote valve off my 57 year old tractor; not too hard to take off and repair......

 

[Texasmark]

Force= Area x PSI. Area didn't change (much) so you look at PSI. What makes PSI? Pump dynamics....design, rotational speed, viscosity of the fluid, and the ability of the container (lines, valves, and seals) to hold the pressure. Fluid viscosity gets thinner so pressure can easily be lost by fluid dynamics, dimensional expansion of pumps....wear factor of the pump plays a big part here, pressure relief and operating valves....springs could have a problem holding the valves to their design specifications, ball bearings (pressure relief valves)...due to age and wear, and connector/line sealing capabilities.

On the temp and viscosity: Why is viscosity important in hydraulic fluids?

 

[RickB]

Operators and manufacturers both seem reluctant to put a pressure guage in the hydraulic line. I have no idea why not. It costs nearly nothing to do and tells you a lot about the hydraulics.
I plumb mine into a T fitting in the pressure line to the FEL control. It's handy, easy to see, and cost about $20 for gauge and fittings.

I've got a couple ideas why. A Bourdin tube style gauge permanently mounted on mobile equipment would easily be the least durable component in the system. Mounted within easy view of the operator it becomes a significant injury threat. High pressure gauges are a great diagnostic tool but as a permanent fixture I think they are a terrible idea.

 

[dieselscout80]

I’m curious why not mount one permanently?

That said I can’t say I have ever seen on a new / factory install.

I‘m not doing anything until I check the pressure.

 

[mark in portugal]

I mounted a pressure gauge on the instrument board of my tractor, I find it very useful.

I also had trouble with the system getting weaker as it got hot, that's why I installed the gauge.
I soon realized the the back pressure was far too high when I was using the hydraulics to power my hedge trimmer.
That caused the oil to become crazy hot, and thin.

After multiple system upgrades, higher flow valves and larger diameter hoses, working pressure is 1/3.
The oil doesn't get as hot and everything works better.

So, we look at pressure, but how's your oil temperature? Is something causing it to get too hot?