Author	[Modern View]
TX641D 07-05-2012 20:04:21 71.170.140.221 Report to Moderator	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. [Reply]   [No Email]
TX641D 07-20-2012 20:20:51 71.170.79.129 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   For Those rookies like me who have to do this: Here are the steps I took to get lift cover off: 641D Lift Cover Removal Summary: 1) Put draft control lever in vertical position, step on lift arms to remove any hydraulic fluid. 2) Remove Top link and lift arm pins. They can be stubborn if they haven't been removed before. The holes in the lift brackets or pins may not line up like they did when new, thus requiring some elbow grease to knock the pins out. 3) Remove Fenders (so not to scratch them) 4) Remove Seat 5) Loosen 11 perimeter bolts around lift cover including the 4 on the accessory cover and the small hex bolt in the center of the accessory cover. Remove the accessory cover and get the last hex bolt (12th in total) securing the lift cover to the chassis. The other 3 interier hex bolts remain in place securing the control unit to the lift cover, so that you don't drop the control unit into the sump. Number the bolts and holes with sharpie so you know where they go upon reinstall. 6) Using a 6' pry bar, pop lift cover from rear by applying pressure under the left lift arm using the differential housing for leverage. 7) Takes two guys to lift the cover straight up and away from tractor. Set on table, control unit facing up. HERE IS HOW IT ENDED 8) Used washers, steel plate, and a machine threaded bolt to remove Unloader Valve plug 9) With help from GURU on the site, got the 0-rings replaced on Unloader Valve and Lift Piston 10) Using a Cherry Picker and 2 7/16 Eye Bolts screwed into the top of the lift cover, lowered lift cover back over tractor 11) Replaced two 0-rings and paper gasket between chassis and lift cover, plus the O-rings beneath the access cover plate. 12) some 7/16 studs in 3 of the holes makes it much easier to replace lift cover Thanks to all for the help!   [Reply]  [No Email]
Kurt-NEPA 07-11-2012 11:26:04 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   I think I used a hard plastic faced hammer. That's what I usually use for things like this. Its a cheapy and I'v had it for over 30 years. Its earned its keep about 1000 times over.   [Reply]  [No Email]
JMOR 07-11-2012 11:04:40 99.34.232.170 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to Bevan, 07-05-2012 20:04:21   Quoting Removed, click Modern View to see...........and if concerned about rolling the edges over, use a wood block or soft (plastic/brass) hammer.   [Reply]  [No Email]
Kurt-NEPA 07-11-2012 03:09:50 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   I just tapped the unloader valve plug back in with a hammer. It actually went in quite easily.   [Reply]  [No Email]
TX641D 07-10-2012 18:15:37 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   I'll work on ensuring the sleeves are smooth. CNH 0-ring will be here tomorrow, so on hold for replacement until then. 1) What is the best method to re-insert the unloader valve plug back into the casing without damaging anything. I am assuming that it was inserted with a press at the factory? What's the best garage version?   [Reply]  [No Email]
Kurt-NEPA 07-10-2012 03:04:43 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   If it felt like it was sticking as you pushed it out, it probably was. The unloader valve should move easily. How dirty does the valve look, especially around o-ring? Take a looks down the bore, Can you see or feel anything? It should be very smooth. I would clean it up with some brake clean and paper towel and take another look. If there is some gunk or corrosion by-product in the bore, you have to get it out. If brake clean doesn't cut it try some 400 or 600 grit silicon carbide wet or dry sand paper and some hydraulic oil. Just polish lightly, don't get carried away. Once the new o-ring in on the valve, lather it up with some hydraulic oil (UTF). Also oil up the bore. Place the unloader valve in the bore. With a rod on one end and a finger on the other, the unloader valve should move back and forth with only slight resistance. It should also feel the same along the length of travel.   [Reply]  [No Email]
TX641D 07-09-2012 19:39:23 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   I tapped it out. Definitely feels like there are some sticking points....but not obvious what is causing them. Lack of experience on what it should feel like is a factor here. However, changing the o-ring is pretty straight forward. 1) Is there a recommended way to polish the inside diameter of the unloader valve? 2) Once the o-ring is replaced....what is the best way to re-install the unloader valve plug back into the housing without damaging something?   [Reply]  [No Email]
JMOR 07-08-2012 21:44:34 99.34.232.170 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to david G, 07-05-2012 20:04:21   "In other words, how do I know whether its normal friction or "stuck"? " That is a judgement/feel sort of thing. For myself, if I try to move it initially & that requires more force that to move it than the next time, I would likely conclude that it was initially stuck & now is un-stuck. Feel for roughness in the area of the position that it is now in...........that is where it has spent most of its life & when sitting for long periods, the most likely place for corrosion, in my humble opinion.   [Reply]  [No Email]
JMOR 07-08-2012 21:38:39 99.34.232.170 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to skjorin, 07-05-2012 20:04:21   Quoting Removed, click Modern View to see From what I see in your pictures, the unloader spool is in a position to have been up against the plug that you removed & if so, then that is the 'bypss/unload" position.....the position "not to lift".   [Reply]  [No Email]
TX641D 07-08-2012 20:28:58 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Success. The Unloader Valve plug is removed. I made a similar removal tool with a 4" piece of steel plate, 1/2 inch hole, a 1/2" Machine threaded bolt, and washers. 2 Questions: 1) How easily should the unloader valve slide in that cylinder? In other words, how do I know whether its normal friction or "stuck"? 2) JMOR or others: From the picture showing the position of the unloader valve....can you tell if that is in "Bypass" position where 3pt would not be lifting? If it is, great. If it's not...then I wonder if I have other problems since the unit would not lift and was all the way down when I took it apart.   [Reply]  [No Email]
Michaels Dad 07-08-2012 06:37:10 209.173.113.5 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to Brian in MA, 07-05-2012 20:04:21   This has been a very lengthy post, but one of the most informative in a long time. To pics posted of every step along the way has been really great for someone wanting to make the same repairs. Great job guys on both ends, keep it coming.   [Reply]  [No Email]
awhtx 07-07-2012 19:12:23 72.26.142.171 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   DO NOT use any o-ring except a genuine CNH NCA836B on the unloading valve. This is not a place where "close enough" will work- that o-ring has to be perfect in size. I will mail you one but it won't go out until Monday now.   [Reply]  [No Email]
JMOR 07-07-2012 17:16:37 99.20.36.34 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to old, 07-05-2012 20:04:21   Quoting Removed, click Modern View to seeUnloading valve spool toward front of tractor (toward the baffle plate & unloading valve plug) is in bypass position, NOT lift position.   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 16:47:26 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Re: Unloader Valve Plug Yep, the plug has to come out to clean and replace the unloader valve o-ring. Some people have put a rod against the unloader valve (from the other end from the plug) and tapped it with a hammer to drive out the plug. I tried that. I hit that rod as hard as I dared, but that plug never budged. The bolt, washer, and plate routine pulled it out easily.   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 16:41:54 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Don't take the cover off the control valve end. It will need a very expensive gasket that is only available from CNH. About $15 if I remember correctly. There is a hole though the plate on the other end. You can stick a rod (screw driver) in there and push the unloader valve out through the plug hole. To do the piston o-ring/back up washer, just disconnect the control valve linkage (pin and cotter pin IIRC), then unbolt the cylinder from the top cover. Using low pressure air (a hand pump will work) on each of the hole on the cylinder until the piston pops out. I forget which hole it is, so just try each one. Be careful, that piston can pop out with lots of force. Pull off the o-ring and back up washer and install the new ones. Soak the back up washer in hot water first. Hyd oil will help them go on. A ring compressor will make putting the piston back in the cylinder much easier. If you don't have one, Auto Zone will lend you one. Now just put the cylinder back on the top cover with new o-rings. Nothing to it. Actually it sounds much worse than it is. I did mine in 20 minutes. BTW, some grease will hold o-rings in position while you get things back together. You've got a lot of them to deal with.   [Reply]  [No Email]
TX641D 07-07-2012 16:34:36 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Couple more things on this unloader valve: As it sits, the end of the unloader piston is about an inch inside the housing on the opposite end of the Unloading Valve Plug. Is that the "bypass" position, which prevents lift? If the piston was toward the end of the Unloading Valve Plug, is that the position for lift? I don't mean to be thick headed, but it seems the only way to get to the unloading valve and O ring, is to remove the Valve Plug...correct? There is no way to get to it otherwise? I think I got confused about the "long rod and push"......but that would be pushing the Unloading Valve into the Plug and tapping both out together, right? Sounds like that has risk of damaging unloading valve and/or cylinder in which it travels? Headed to hardware store to get the materials to pull that plug like the earlier picture. thanks!   [Reply]  [No Email]
TX641D 07-07-2012 16:01:05 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to david G, 07-05-2012 20:04:21   Ok...i'll take the cover off both ends and try the push approach, checking to see if it was stuck. Don't know about replacing piston O Ring and Washer. Is it hard? Does it required disassembling something which requires calibration upon reassembly?   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 15:44:55 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Your cam follower pin looks decent. can you lift the linkage and see if deep groove is worn into it? To get the unloader valve out pull the cover in your second picture No gasket here. There is a plug under that cover. It needs to come out. I would fashion a puller like I described earlier. Your Tisco gasket kit should have everything you need. The problem is identifying the right o-ring for the unloader valve. I got mine from CNH just to be sure. Once the plug is out, the unloader valve should move easily. You can use a long rod from the other end to push it. If doesn't move easily, you may have found your problem. Are you going to replace the piston o-ring and back up washer?   [Reply]  [No Email]
TX641D 07-07-2012 15:27:28 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Questions: 1) Do I undo the holding in the Baffle plate and the Retainer Plate (terms from manual for covers on both ends of control unit housing where unloader valve is?) 2) Included a pic of my cam pin. Doesn't look worn. I would have to order a new one. Not sure how to remove / replace. 3) Can I access unloader valve without messing up draft control and position control linkages? I'd really hate to undo those....i don't think I could get them adjusted back to where they need to be. 4) I guess I need to order new gaskets if I remove Baffle and Retainer plates. they are not included in the Lift Gasket Kit I ordered. I guess any o-rings for unloader valve are also not in the Lift Cover gasket kit?   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 15:04:41 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Perfect!   [Reply]  [No Email]
TX641D 07-07-2012 14:54:55 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   For Those rookies like me who have to do this: Here are the steps I took to get lift cover off: 641D Lift Cover Removal Summary: 1) Put draft control lever in vertical position, step on lift arms to remove any hydraulic fluid. 2) Remove Top link and lift arm pins. They can be stubborn if they haven't been removed before. The holes in the lift brackets or pins may not line up like they did when new, thus requiring some elbow grease to knock the pins out. 3) Remove Fenders (so not to scratch them) 4) Remove Seat 5) Loosen 11 perimeter bolts around lift cover including the 4 on the accessory cover and the small hex bolt in the center of the accessory cover. Remove the accessory cover and get the last hex bolt (12th in total) securing the lift cover to the chassis. The other 3 interier hex bolts remain in place securing the control unit to the lift cover, so that you don't drop the control unit into the sump. Number the bolts and holes with sharpie so you know where they go upon reinstall. 6) Using a 6' pry bar, pop lift cover from rear by applying pressure under the left lift arm using the differential housing for leverage. 7) Takes two guys to lift the cover straight up and away from tractor. Set on table, control unit facing up.   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 14:46:51 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Also, check the cam follower pin - How badly worn is it? Since you are in this far, I would replace the piston o-ring and back up washer. I assume you have the top cover gasket and o-ring set. You'll need it.   [Reply]  [No Email]
JMOR 07-07-2012 14:39:49 99.20.36.34 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to Kurt-NEPA, 07-05-2012 20:04:21   Since the unloader was suspect, I would go for it first, just out of curiosity. Once you get the unloader plug out, you will be able to move unloader spool with your finger thru that opening & move it the other way with a probe thru hole at other end of spool. Feel gently to see if you call tell if it was stuck & maybe toward which end it was stuck?   [Reply]  [No Email]
TX641D 07-07-2012 14:25:27 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   OK.....lift cover off! Now what? :)   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 12:58:48 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   I got mine off with a crow bar. Try what you "got" before you spend $$$. I just went out and counted my bolts. There are 14. 12 around the perimeter. Plus one though the accessory plate and one under the accessory plate. Looking at your picture, you have 12 loose for sure. There are two at the back that I can't see. If you got them you are ready to go. My Sharpie numbers are still there on mine, numbered 2 thu 14. With number one under the plate. Some day I've get some paint on it.   [Reply]  [No Email]
Royse 07-07-2012 12:45:18 69.36.49.151 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to awhtx, 07-05-2012 20:04:21   A T-post or 2x4 would work fine if it's not stuck too tightly. But then, that wouldn't get us new tools, would it? :lol: Good luck! I've got to do one shortly, so I'm watching and learning as you go.   [Reply]  [No Email]
TX641D 07-07-2012 12:40:27 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   I have 13 bolts loose. 12 around the perimeter, 1 under the accessory cover. The slot head bolt under the accessory cover, I did not loosen. Am I missing one? Running to Northern Tool. I don't have a pry bar like that, but i will shortly :) Back in 45 mins   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 12:37:14 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Looks good to me. I see you found the bolt under the accessory plate. BTW that other "bolt" under the accessory plate, the one with slot on it is the safety valve. Don't mess with that if you don't have to. They rarely go bad. Do you have the three pins off that attach the top cover to the 3pt lift? You might want to number the bolts with a Sharpie. A number on the bolt and one on top cover. Sure makes it easier to get them back into the right position. Time for the pry bar trick. That gasket really get stuck on there sometimes. Keep us posted.   [Reply]  [No Email]
JMOR 07-07-2012 12:32:04 99.20.36.34 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to Vito, 07-05-2012 20:04:21   I believe 14 it right number....looks like you have more than enough. Technique:   [Reply]  [No Email]
TX641D 07-07-2012 12:03:06 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to J. J. R., 07-05-2012 20:04:21     [Reply]  [No Email]
TX641D 07-07-2012 12:01:41 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Ok...accessory cover is off and the last 11/16 bolt loosed (fine threads). Now, do I have everything loose for the cover to come off? [img] http://ytforums.ytmag.com/photos/8996.jpg[/img]   [Reply]  [No Email]
Brian Allen 07-07-2012 11:45:16 74.198.87.56 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   TX641D That plate at the front of the cover has to come off. It is a blank plate for the hydraulics. (That is where a hydraulic valve would mount) Pull the stand pipe out too, if it did not come out with the blank. Use a small steel wedge or a thin screw driver to start it moving. Note: double check that you have removed all the bolts before you damage anything. Good luck Brian   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 11:36:35 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   You'll need to get the accessory plate off. Remove the small bolt in the center and all the others. If my memory is any good (I have a bad case of CRS) one of the accessory plate bolts goes through to the cylinder. Not a problem to remove just this one. Once the plate is off. There is one more bolt going into center housing. Sorry if my earlier post may have confused you - I lost count of the accessory plate bolt count. Once you are sure all the perimeter bolts are out. Take a long pry bar and go around the back of tractor. Get under the top cover and pry down on the center section. The cover usually comes up with just some moderate pressure. Maybe these pictures will help once you get the lid off.   [Reply]  [No Email]
TX641D 07-07-2012 11:19:46 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   All the perimeter bolts are loose plus the 4 on the top accessory cover. There is a smaller hex bolt in the center and 3 others in the center which I have left in place, per your instruction. If you agree I have all the right ones loose, what is the best way to break the lift cover free? Do i lift on the spring, or lift arms, or?? I don't want to break it, but it seems like it will take a lot of pressure to break it free?   [Reply]  [No Email]
Kurt-NEPA 07-07-2012 05:31:48 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Right On awhtx. Good catch. Always replace the cam follower pin. Also - The I&T Manual F0-20 has the procedure for adjustment. Zane Sherman also sell a really nice adjustment manual and it come complete with gauges and a new cam follower pin. Well worth the price. I see nobody mentioned the 4 cylinder bolts. When you pull the top cover, remove only the bolts on the outer perimeter and the 5 bolts on the 3X5 accessory plate. The other 4 bolts are in the center of the top cover. They hold the cylinder in place. If you take them out, the cylinder will fall into the sump. If you pull out a bolt with fine threads, put it back in. For me, I break the cylinder bolts loose a bit before I pull the top cover. Once the top cover is off I remove the cylinder bolts and then use low pressure compressed air to pop out the piston. Note that I said low pressure. Even that will launch the piston out of the cylinder and bounce it off some valuable like your head. Be careful with this. This post was edited by Kurt-NEPA at 05:50:33 07/07/12.   [Reply]  [No Email]
awhtx 07-07-2012 05:18:12 72.26.142.171 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   And none of us has mentioned the cam follower pin. It will surely need to be replaced.   [Reply]  [No Email]
Kurt-NEPA 07-06-2012 18:48:26 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   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.   [Reply]  [No Email]
TX641D 07-06-2012 18:22:43 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   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?   [Reply]  [No Email]
awhtx 07-06-2012 18:49:07 72.26.142.171 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-06-2012 18:22:43   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.   [Reply]  [No Email]
TX641D 07-06-2012 18:02:11 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Thanks. I need you to resend me your email address. send to steve.loop@verizon.net or text it to 210-287-5667.   [Reply]  [No Email]
awhtx 07-06-2012 16:08:37 72.26.142.171 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   Steve, I'll be home Thursday-Sunday. Send me an e-mail. Alan   [Reply]  [No Email]
soundguy 07-06-2012 15:34:24 107.41.89.210 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   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..   [Reply]  [No Email]
Kurt-NEPA 07-06-2012 14:05:51 70.44.245.96 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   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.   [Reply]  [No Email]
JMOR 07-06-2012 06:05:58 99.20.36.34 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to old, 07-05-2012 20:04:21   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.   [Reply]  [No Email]
JMOR 07-06-2012 05:38:29 99.20.36.34 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to bill.nash, 07-05-2012 20:04:21   Quoting Removed, click Modern View to seeI don't have any of my notes or books with me, there is such a shift detent spring & ball on the "Ns", but I'm not sure the 641 uses that same detent scheme......I'm thinking it may not. George Marsh & Kurt-NRPA have a lot of experience with their own hydraulics & will have a lot of pictures somewhere here on YT. Geo has Jubilee & Kurt a hundred series I believe, but even the Jubilee has a great deal of similarity as well as many differences.   [Reply]  [No Email]
TX641D 07-05-2012 20:26:15 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:04:21   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?   [Reply]  [No Email]
Jerry/MT 07-06-2012 07:52:46 206.183.116.145 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:26:15   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.   [Reply]  [No Email]
TX641D 07-05-2012 20:24:09 71.170.140.221 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to dogobat, 07-05-2012 20:04:21   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.   [Reply]  [No Email]
Jim.UT 07-06-2012 10:31:17 70.89.244.178 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to TX641D, 07-05-2012 20:24:09   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!   [Reply]  [No Email]
JMOR 07-05-2012 20:12:14 99.20.36.34 Report to Moderator	Re: 641D 3pt Lift Cover rebuild in reply to dogobat, 07-05-2012 20:04:21   Quoting Removed, click Modern View to seeMore than wish I could be there to help, but it isn't in the cards right now.   [Reply]  [No Email]