# Lift Arms Jumping Up



## danny bell (Apr 12, 2020)

I have seen it before somewhere but cant find it. What is the reason my Ford 3000 rear lift arms are jumping up every minute?


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## Ed Williams (Jun 13, 2019)

You could have one of two problems. The first thought is the safety valve inside under the top cover is popping off, usually from a weak spring. The other can be leaking lift cylinder seals. You can take out the fill plug on the diff. The tractor must be running with the lift arms at the highest position. Shine a small bright light in the hole facing forward. If you see a lot of fluid splashing like a waterfall fom the seat area, it is most likely the lift piston seals are worn out. If you only see a small amoun of fluid splashing it is most likely the safety valve popping. The NAA was easy to diagnois as the lift was very weak when the piston seals were leaking. The lift was still strong when the safety was popping off, causing a hicup at the lift arms. It would have been nice for both to go bad at once instead ot 10 years apart. If its the safety, it will get worse over time until it becomes hard to even attach implements with the arms jumping.


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## Ultradog (Feb 27, 2005)

Ed Williams said:


> You could have one of two problems. The first thought is the safety valve inside under the top cover is popping off, usually from a weak spring. The other can be leaking lift cylinder seals. You can take out the fill plug on the diff. The tractor must be running with the lift arms at the highest position. Shine a small bright light in the hole facing forward. If you see a lot of fluid splashing like a waterfall fom the seat area, it is most likely the lift piston seals are worn out. If you only see a small amoun of fluid splashing it is most likely the safety valve popping. The NAA was easy to diagnois as the lift was very weak when the piston seals were leaking. The lift was still strong when the safety was popping off, causing a hicup at the lift arms. It would have been nice for both to go bad at once instead ot 10 years apart. If its the safety, it will get worse over time until it becomes hard to even attach implements with the arms jumping.


Ed, twice you have mentioned the "safety valve inside under the cover". There is no such animal on a 3 cylinder Ford.
Yes, they do have a pressure relief valve (PRV) in the system.
On a 4000 it screws into the pump body.
On a 3000 it screws into the chassis down by where the hydraulic lines enter the rear housing.
Both are Externally Mounted.
They never, ever go bad or get weak. I have never even heard of one having a problem.
I once was having a hydraulic problem on a 3000 and called the dealer to order a new PRV.
Good, old school parts man said it was not my problem. He said he can look up all the way back to the early 1990s when they computerized all their parts stuff and they had never sold one.
Ever!
If you are thinking it is his unloader valve that is sticking that would not cause his stated problem.
If the ULV is stuck open the system just goes into bypass and the arms won't lift. If it is stuck closed the arms will lift but will not lower. Again, not his stated problem.

Danny Bell, it is the seals in your lift piston that are leaking badly. Time to pull the lift cover and renew them.


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## Ed Williams (Jun 13, 2019)

Ultradog, Thanks for setting me straight. I guess I had the NAA on my mind. Had to change 4 of those on mine and family members tractors. Blame senility. I should have taken the time to go through the hydraulics in the shop manual before replying. Please forgive my ignorance of the newer hydraulic setup on the later models.

I had a very bad incident when I was 17 and changing the motor on Dad's tool truck. His NAA had been having the lift hickups for quite a while. When we were pulling the motor and tranny, it changed from a small to large jump, crushing my hand between the boom pole and upper firewall housing. I guess I am haunted by this experience as it is the first thing that pops into my head when I hear of lift arms jumping. Sorry for giving out bad info. It was not intentional. I will put aside some time to review the new hydraulics arrangement.


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## Ultradog (Feb 27, 2005)

Ed Williams said:


> Ultradog, Thanks for setting me straight. I guess I had the NAA on my mind. Had to change 4 of those on mine and family members tractors. Blame senility. I should have taken the time to go through the hydraulics in the shop manual before replying. Please forgive my ignorance of the newer hydraulic setup on the later models.
> 
> I had a very bad incident when I was 17 and changing the motor on Dad's tool truck. His NAA had been having the lift hickups for quite a while. When we were pulling the motor and tranny, it changed from a small to large jump, crushing my hand between the boom pole and upper firewall housing. I guess I am haunted by this experience as it is the first thing that pops into my head when I hear of lift arms jumping. Sorry for giving out bad info. It was not intentional. I will put aside some time to review the new hydraulics arrangement.


No harm, no foul Ed.
Just trying to keep the info here as accurate as possible.


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