model 630 lift arm issues

Thanks to all the great info so far. I'm new to tractors as well as forums, so bear with me as I figure it out.

I have a model 630. First off, the "float position lever"(small lever directly under seat on right hand side)was wire tied to the up position when I got the tractor. So, the lift arms constantly slowly fall and occasionally quickly slam back up but then will just slowly fall again. How do I fix this?

looking at pictures I guess its an implement position control

(quoted from post at 21:50:49 09/21/15) Thanks to all the great info so far. I'm new to tractors as well as forums, so bear with me as I figure it out.

I have a model 630. First off, the "float position lever"(small lever directly under seat on right hand side)was wire tied to the up position when I got the tractor. So, the lift arms constantly slowly fall and occasionally quickly slam back up but then will just slowly fall again. How do I fix this?

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The small lever is called the draft control lever. In the "up" position the system is in position control mode, and in the "down" position the system is in draft control mode. The fact that it is tied up with wire indicates that there is probably a lot of slop in the linkage inside that would allow it to fall down on its own if it were not tied up, as normally it would hold itself in place, but that should have nothing to do with the symptom you are describing, which is referred to as hiccupping. Hiccupping is caused by an internal leak in the system which allows the lift arms to drift down, and when the system is in position control mode it has a mechanism that senses the arms drifting down and tries to correct for that and moves the arms back up to the proper height as indicated by the position of the touch handle.

Since the draft control lever needs to be tied up to stay in position control mode, and the system is hiccupping, it sounds like it needs to have the hydraulic top cover removed and serviced, which includes replacing all of the seals inside plus all of the adjustment procedures in the service manual should be performed before putting the top cover back on. Most likely the cam follower pin will need to be replaced as well, and maybe the cam might need to be welded up if it is worn a lot.

First thing you should do is get yourself a service manual. The Ford service manual can be expensive, but the I&T aftermarket manual is generally less than $30.00, and it has "alternate" procedures for some of the adjustments that need to be made that don't require the special tools that the procedures in the Ford service manual require.