641D 3pt Lift Cover rebuild

[TX641D]

3pt lift has finally stopped lifting altogether. With FO-20 manual in hand and the CNH gasket kit full of O-Rings, I am contemplating diving into the 3pt cover to "un-stick" the unloading valve.

Honestly, I have put it off this long because I am not confident I can get it back together if I tear into it. It's pretty worthless when the 3pt unit doesnt work, so i'm tempted to try.

1) Anyone who has done this specific rebuild, any tips or pitfalls I should lookout for?

2) Awhtx...I have a tractor in my barn with your name on it I may be passing thru next week, bringing my boys to their grandparents in San Antonio.
 

[JMOR]

[TX641D]

My friend...you are right where you need to be. Thanks for the note.

I'll be posting the steps here with pictures...so as I learn and fumble, it will be documented for the next guy.
 

[TX641D]

JMOR,

Do I remember you cautioning me about some spring or linkage just beneath the cover, when you unbolt it?

Can you refresh my memory on what I'm watching for?
 

[JMOR]

[JMOR]

When you remove the plug from the front of lift cover to access the check valve & back pressure valve components, pay attention to order/orientation of the parts, as the manual & pictures by various posters does not make it clear as to orientation/position. Pretty sure the picture with all strung out in line here is incorrect.



 

[Jerry/MT]

Pardon me for stepping in but I think JMOR was cautioning you about the removal of the top link feedback rod before you remove the lift cover.
 

[Jim.UT]

Yes, please document your adventure. I need to dig
into the lift of one of my 850's soon and am at the
same confidence level as you!
 

[Kurt-NEPA]

No Toplink feed back rod on my 660 that would get in the way with pulling the cover. Pulling the top cover is straight forward. Just remove the seat and 3 pins, then a bunch of bolts. Lift it straight up. The linkage may hang up on the right side. Just push it the left a bit. Remember that one top cover bolt is under the 3" X 5" accessory plate.

I think JMOR has the back pressure and check valve covered well. They seldom cause problem.

Post back if you need help getting the unloader valve out. It can be a little bit challenging.

When you put the top cover back on, getting everything lined up with the gasket is fun. An extra set of hands helps. I cut the heads off several long 7/16" bolts and threaded them in. Then slipped the gasket over them. Dropped the top cover over the bolts and onto the center housing. I put in the remaining bolts, removed the long bolts and replaced them with the original bolts. Then torqued it up.

Have fun, actually this job is much easier than it sounds.
 

[souNdguy]

i think you will be fine.

ove rthe years I've rebuilt many N lift covers,a nd had helped rebuild a couple 00 series.. but had never puleld an 00 series as of ? i dunno.. 06 maybee.. didn't know if there were any tricks like the back pressure valve on a naa.. etc. got the same good advice you just got.. 'dive in'

it really is no big deal. the pulling is the easiest part.. and the rest is just figidity orings and getting it all back together with no leftover parts.. :)

ps.. the lil option cover has a couple bolts that go thru the top cover..
 

[awhtx]

Steve,
I'll be home Thursday-Sunday. Send me an e-mail.
Alan
 

[TX641D]

Thanks. I need you to resend me your email address. send to steve.loop@verizon.net or text it to 210-287-5667.
 

[TX641D]

Nuday tool No. N-508-A

What do I do, if I don't have this tool? It says this is required to remove the control valve bushing. Also, the FO-20 Manual says "an impact puller adapter" can be threaded into the unloading valve plug to remove it. Is that the same tool as the Nuday tool above, or different? If different, where do I get one of those?
 

[Kurt-NEPA]

Gotta love those Nuday tools that nobody has anymore.

The control valve will come out easily once you remove the plate. As to the bushing, I wouldn't go there.

For getting the unloader valve out - some people have been able to just tap it out with a long rod. There is a plug on one end. Put a rod in the other of the valve and tap. For me, that didn't work, so on to plan B. I got a fine thread bolt, some washers, and a bearing separator (any plate with a hole will work)





I just tightened the bolt and pulled the plug. I had to add washers under the plate several times to get the plug all the way out. Once the plug is out, the unloader valve will push out easily.

Caution on the control valve. Its a metal to metal seal. Do not use any abrasive on the bore or valve. Just pull it out and clean out any junk with some oil or brake clean.
 

[awhtx]

I have rebuilt a couple of lift covers and I did not remove the control valve bushing. You only need to remove it if you are going to replace it. All I did was replace the o-ring and backup ring on the lift piston and the o-ring on the unloading valve. Then I adjusted the linkage per the I&T Manual.