ford 641 hydraulic issues

Kool · Sep 24, 2017

i apologize in advance i am new to this.here goes.i am working on a 1955 ford 641 and the hydraulics are pulsing up and down and there is a lot of air in the fluid i replaced hydraulic manifold o-rings
and rebuilt lift cover and adjusted the lift cover as the manual says
to and the problem is still there and was wondering if anyone had any ideas of where i should go next.THANKS in advance.

old · Sep 24, 2017

641?? The 601/641 did not come out till 1958. The 600/640 was made from 1955 to 1957. As for the hyd problem could be the unloader valve sticking at times or sucking air some place

Kool · Sep 24, 2017

i apologize that was the wrong year the serial number comes up as 1957 not 1955.Could an air leak cause the bouncing on the 3 point

Sean in PA · Sep 25, 2017

The 3 point "pulsing up and down" also known as "hiccuping" is caused by a leak in the lift cylinder seal that allows the arms to lower, and the auto sensing in the control linkage detects the drop and opens the valve allowing fluid into the cuylindr to compensate and bring the height back up to where you had it set. It repeats over and over because as soon as it's back up to proper heigfht the valve closes and then it begins to leak down again and the pattern repeats. Best thing to do is buy a hydraulic top cover repair kit which has all of the seals and o-rings needed, and then to take the lift cover off and replace all of the seals and o-rings and follow all of the adjustment procedures in the service manual before putting it back together.

Kool · Sep 25, 2017

(quoted from post at 12:19:34 09/25/17) The 3 point "pulsing up and down" also known as "hiccuping" is caused by a leak in the lift cylinder seal that allows the arms to lower, and the auto sensing in the control linkage detects the drop and opens the valve allowing fluid into the cuylindr to compensate and bring the height back up to where you had it set. It repeats over and over because as soon as it's back up to proper heigfht the valve closes and then it begins to leak down again and the pattern repeats. Best thing to do is buy a hydraulic top cover repair kit which has all of the seals and o-rings needed, and then to take the lift cover off and replace all of the seals and o-rings and follow all of the adjustment procedures in the service manual before putting it back together.

I did a rebuild on the lift cover all o-rings replaced and repaired the pin and adjusted lift cover per manual instructions. But I put a camera through the fill hole and noticed there is fluid coming out from the unloader valve could this be a bad relief valve

ford 641 hydraulic issues

Kool

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old

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Sean in PA

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