640 lift

[grandpa Love]

I'm sure the answer is here somewhere but after the update I can't find how to search archives. Ford 640. Replaced cam follower pin and adjusted the lift a couple months ago. It worked great for a couple weeks. Now it will lift smooth with a light implement, but anything heavy it has issues. With heavy implements it won't lift at all until you pull lever all the way up past the stop. Then it will lift until it almost hits the fenders. If you move lever down at all it slams implement to the ground. Worst is the tedder-rake, 950 lbs and sometimes wont lift at all unless you push the little draft lever down. Not down and locked , just move it a quarter way down and then it will lift. But when you let off it drifts down quickly. Really hard to cut and rake hay. Fluid is full. Could the new cam follower pin fall out?? Thanks for any help. Using the tractor today on a fence job in the boonies so I won't have cell service until later this afternoon. Hopefully yall can come up with a fix for me! Got several days of nice weather starting tomorrow and need to cut hay with the sickle mower. Narrow gates at new field and haybine won't fit.

 

[john in la]

Sounds like it is in draft control that is used for plowing.

What position is the draft lever in. Does moving it make a difference.

 

[JMOR]

(quoted from post at 09:04:10 06/10/20) I'm sure the answer is here somewhere but after the update I can't find how to search archives. Ford 640. Replaced cam follower pin and adjusted the lift a couple months ago. It worked great for a couple weeks. Now it will lift smooth with a light implement, but anything heavy it has issues. With heavy implements it won't lift at all until you pull lever all the way up past the stop. Then it will lift until it almost hits the fenders. If you move lever down at all it slams implement to the ground. Worst is the tedder-rake, 950 lbs and sometimes wont lift at all unless you push the little draft lever down. Not down and locked , just move it a quarter way down and then it will lift. But when you let off it drifts down quickly. Really hard to cut and rake hay. Fluid is full. Could the new cam follower pin fall out?? Thanks for any help. Using the tractor today on a fence job in the boonies so I won't have cell service until later this afternoon. Hopefully yall can come up with a fix for me! Got several days of nice weather starting tomorrow and need to cut hay with the sickle mower. Narrow gates at new field and haybine won't fit.

he reason it lifts when you push on the Draft lever is that by that 'push' you are compressing the spring on the postion control mechanism, thus pushing the control arm toward the 'lift' position. You need to find the reason that touch control can not push as far into 'lift' position. Most likely cause in mal-adjustment, but some part could be bent.

 

[grandpa Love]

Adjusted the lift yesterday. 99.99% sure
it's right. Still no good today. Really
doesn't like a sickle mower. Will lift
and get stuck. Then suddenly slam to
ground. Wont stop until it's all the way
up.

 

[Dean]

Agree with earlier posters. Cam follower pin/mis adjustment, draft control, etc.

If you replace the cam follower pin and adjust the draft and position control linkages precisely as directed in the FO-20 manual (alternative procedures) the adjustments will be quite close.

Be CERTAIN to replace the cam follower pin if there is ANY perceptible wear.

Dean

 

[grandpa Love]

Dean. New cam follower pin. 99.99% sure adjustments are correct. Could be an issue with mower? And way it hooks up? Re adjusted yesterday. No change.

 

[JMOR]

I would see how lift performs with nothing connected to top link.

 

[grandpa Love]

JMOR. Lifts mower fine if cutter arm is
up. Only has issues with it down in
cutting position.

 

[JMOR]

(quoted from post at 17:39:34 06/12/20) JMOR. Lifts mower fine if cutter arm is
up. Only has issues with it down in
cutting position.

am not familiar with that mower hookup, but if I were a gambling person, I would bet that it is getting a Draft link input thru the top link rocker/spring assy and interfering with the Position control. It only needs a fraction of an inch to foul it. If you study the internal linkage, you will see that when in Position control, the Draft input isn't truly "disconnected", but rather simply positioned in a 'dead zone' where it doesn't provide an input. But if the input is large enough from the draft control plunger, it will in effect re- connect the draft input. In the picture, you can see the Draft control swivel (#957E692) is sliding freely on Draft Control Bushing (NCA691A). If and when swivel is not in this 'free floating" position (swivel NOT contacting C or D) and contacts end of bushing, then you have a Draft Control input to the control valve.
This pix is 8N, but in this regard, is same and I don't have a good pix of this swivel for your 641. The second picture shows a small "gap" & when this gap does not exist, you have a draft control input & I expect that your "slam" is at a point where Draft input goes away suddenly. It should not have ever existed, but due to perhaps bent linkage, odd (to me) mower connections, whatever, the draft in put is at some point occurring.