7710 - 3PT Lift issue

4500GUY

Member
Hi Gents,

I have been searching many posts from others in regards to 3 pt lift issues.

I recently acquired a 1982 7710 with the dual pump setup and (2) sets of rear remotes. The lift and remotes work, but.....

The lift will raise a heavy implement to full height, but as soon as I drop the lift lever slightly and stop, the lift arms will pulsate with enough force to shake the tractor. Push the lift control to full up and the pulsing stops. Remotes seem to have good power.

I have yet to test the pressure on the main pump. All fluid and filters have been changed. I also pulled the priority pack, disassembled, cleaned and re-installed. Nothing plugged that I noticed, but the sequencing valve seemed to be tight in the bore. I removed any sharp edges / burrs off the valves with ultra fine emery.

Another thing I noted, is that when the fluid warms up to temp, the lift will not raise the implement nearly as high. Seems like there is a lot more leakage. Lift cylinder seals?

What would you suggest as my next move? I will see what pressure I get at the main pump. Can I just put a gauge at the remote to test?

Thanks!

- Dave
 
The system selector may be in 'Load Monitor' mode... Make sure it's set in 'Position' or 'Draft' mode and try again. If it's still doing that
I'd wager there's wear in the system selector lever internally. If that's the case you're pulling the lift cover for a rebuild and reset,
which is a bit of a job in itself.

Rod
 
The pulsing is clearly a lift control valve issue internal to the lift cylinder, meaning you'd have to pull the top cover to access. Ford had
issues with the early 10 series lift control valves, and there was at least one, if not more service bulletins regarding this issue in the
early-mid 1980s. Problem is, it's been way too many years ago for me to remember the details, so I'd suggest you head over to your local
dealer and see if they still have any copies. This assumes of course that Rod and others don't remember the details.

I want to say that it involves a broken spring, but don't quote me for certain on that. I think it was something to do with #28 in the link
below?? Rod?
Spring
 
Rod,

I was trying the selector lever in various positions to see if I could find a setting where the pulsing would reduce. Seems the closer I moved the selector lever to full draft mode (Fully forward), the pulsing would reduce some, but not totally disappear.

So looks like I am pulling the cover at least. Fortunately, my tractor does not have a cab, so hopefully that will make the job a bit easier.

Thanks so much for your insights! I'm sure I will have more questions!

- Dave
 
Bern,

I will certainly check out that bulletin regarding that valve.

Since I will be removing the lift cover, I will be checking what you & Rod suggested. I should replace the lift cylinder seals while I am in there, right?

Thank you!

- Dave
 
(quoted from post at 04:29:38 02/13/18) The pulsing is clearly a lift control valve issue internal to the lift cylinder, meaning you'd have to pull the top cover to access. Ford had
issues with the early 10 series lift control valves, and there was at least one, if not more service bulletins regarding this issue in the
early-mid 1980s. Problem is, it's been way too many years ago for me to remember the details, so I'd suggest you head over to your local
dealer and see if they still have any copies. This assumes of course that Rod and others don't remember the details.

I want to say that it involves a broken spring, but don't quote me for certain on that. I think it was something to do with #28 in the link
below?? Rod?

Rod,

Do you have any thoughts on the service bulletin that Bern is referring to in regards to the lift control valve?

Thanks!

- Dave
 
You may be correct. I don't know. It's close to 15 years since I was into mine.. but it's due this spring once the blower comes off because it won't lift properly right now either. Mine simply won't execute a lift cycle in position. In LM it will lift... as erratically as they work.

Rod
 
Haha, no.. it won't make it any easier. The platform is the same as the cab lower half. Just remember to get he bolt under the right rock
shaft... and prop the cover up enough to slip your hand in at the right rear and get the LM link. Otherwise, go carefully... and wiggle it
out.

Rod
 
Hey Gents,

Well, I got the cover removed and have the lift cylinder removed from the cover. I carefully removed all valve assemblies etc. from the housing. The parts seem to look good and no broken springs. Valves showed very light scoring. The piston seals felt pretty loose, so will definitely be replacing those.

The linkage, as far as I can tell, looks good. I'm not seeing a bunch of worn thru holes. I'm guessing some play is built in to prevent binding?

I still need to contact the local dealer regarding any service bulletins for the valves and to see if they have dealt with rebuilding of the lift cylinder and setting the linkages.

Looking at the parts breakdown, there are part numbers that have been superseded. Also, a service bulletin number (9-90 T2)

How do you identify the valve colors? Are they actually paint marked in some way? I see various valve part numbers, with different diameters shown in the parts listing.

Also, could the lift cylinder relief valve be faulty? Would that cause the pulsating in the lift arms? Can the relief valve be tested by the dealer or should I just replace it?

Sorry for all the questions, just trying to get this right the first time around.

Thanks for your patience!!

- Dave
 
Bern / Rod,

Looks like your memory serves well! I was able to get a copy of the Ford service bulletin 9-90 T2. The symptoms listed are excessive corrections / leakdown. Sounds like exactly what I have going on.

The fix is an updated lift control valve and a kit, which contains other parts to block off a port where the poppet valve used to be and to add a replaceable seat to the existing check ball seat in the priority unload valve. This also requires the priority valve be machined to accept the new seat.

Overall, not too bad, a few hundred bucks and my labor. Hopefully, this is it! Thanks for the tips!

- Dave
 

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