Hydraulic issue on 1980 Ford 1500

[TexasRN]

Howdy all,
Long time lurker and now a new member with a question.

We have as stated we have a 1980 Ford 1500 that has a hydraulic issue. What happens is that intermittently the hydraulics won't keep our plow lifted off of the ground. However, if we shut the tractor down, let it cool off and start it back up the hydraulics will keep the plow in the up position. After a period of time (20 - 30 minutes) it slowly lowers back to the ground. The fluid level indicates that there is plenty of fluid in it, no obvious leaks or noises. Don't really know where to start looking for the problem. Apologies in advance if I used wrong terminology, city folks turned country and it's a heck of a learning process.

Thanks,
Cam

 

[J_J]

You probably have some leaking seals on the 3pt piston, or the 3pt valve is leaking.

The 3pt valve might not be going back to neutral also.

If you have a descent rate knob that adjust the speed of drop, or will lock the 3pt for transport, you can lock it down and see if the cyl will leak down. If so, you probably have worn seals on the 3pt piston.

 

[TexasRN]

Thanks for the input J_J. Does it make any difference if we can lift the 3pt "arms" and they will stay up (with no implement), and then use the controls to lower them. I guess with the weight on there it would indicate a leak somewhere.

 

[birddog0304]

Check you hydraulic fluid type. Some of the cheaper brands may have a lower viscosity or allow foaming(entrainment). Either way what happens as the fluid heats up the viscosity is lowered. This results in you not being able to maintain your hydraulic pressure or having to increase rpm to keep hydraulic pressure up. Also check your filters to make sure they're not clogging up. Next time it happens take a pic of a sample in a glass bottle and post it. All of this of course is after you have tried JJ's recommendations.

 

[J_J]

In a perfect 3pt system, the 3pt system should hold an implement for a very long time.

However, even the smallest leak in the seals, relief valve, or valve spool, the load might descend.

The knob for rate of descent, will or is supposed to block any fluid from the cyl for transport. It could leak some.

If you know how to open up the 3pt, you can replace the seals on the piston, and that might solve or help the situation. You could remove the relief valve and inspect and clean, and re-install.

There is also a safety valve in the system, but it usually stays secure until the safety pressure psi is met.

 

[jinman]

What happens is that intermittently the hydraulics won't keep our plow lifted off of the ground. However, if we shut the tractor down, let it cool off and start it back up the hydraulics will keep the plow in the up position. After a period of time (20 - 30 minutes) it slowly lowers back to the ground. The fluid level indicates that there is plenty of fluid in it, no obvious leaks or noises.

Cam, I want to understand the parameters of your 3PH problem a little better. You said that the lift drops after the tractor warms up, but only intermittently. Is that with the tractor running? If I understand, you are saying that the lift will lower while the tractor's engine is running. Also, how about your lift lever? Is it going down or staying in the up position? If the lever is going down, you probably only need to adjust the tension nut to make it a bit stiffer in operation. If the lever is staying in the up position and the tractor is running while the 3PH drops, then certainly you have a leak or your hydraulic pump may be weak. Do you have a loader also? If you have a loader and it works fine, then most likely the problem is isolated to the 3PH and not the pump.