Author	[Modern View]
Canadian Ken 07-25-2012 20:49:43 74.114.77.214 Report to Moderator	Removed worm housing and removed shims to get .040" backlash-- jacked up front wheels - while engine stopped turned steering wheel -wheels turned ok -caught a couple of times -started tractor -steering would catch at different spots -erratic steering from full left to full right - dismantled worm housing - dowels have a slight flat area on the sides - the cam stud is slightly bent -groove worn in one side where cam rotates - can't really see any other issues - stud not available from Deere -is the groove worn in causing the catching??? should the dowel pins have no wear at all?? Ken [Reply]   [No Email]
F-I-T 07-26-2012 06:17:13 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to Canadian Ken, 07-25-2012 20:49:43   You certainly make a new rod easily enough. It's standard 5/16" coarse thread. I'd be surprised that you can't straighten it well enough. How in the world would that get bent in the first place?!? That "catching" you are feeling, I still think, is likely caused by flats on pins, and sharp edged divots on the cam faces. Worm end play is suppoed closer to .001", right? I'd have to look that up, but any extra endplay will add to slow response. Meaning that you will have to turn the wheels farther to get assist. [Reply]  [No Email]
Canadian Ken 07-27-2012 11:49:39 64.235.98.126 Report to Moderator	Re: JD 620 power steering pics in reply to F-I-T, 07-26-2012 06:17:13   The tractor serial # is 6211122 - the actuating sleeve is AR20168R for later tractors -no AR20913R screw - the tapered bearings appear good -dowel pins have minimum, but a slight flat spot - scoring inside sleeve? -steering worm has mark on worm and the end has chip out of it -the rod has a very slight bend - I cannot see anything the jumps out for the catching? -combination? [Reply]  [No Email]
F-I-T 07-26-2012 05:09:20 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to Canadian Ken, 07-25-2012 20:49:43   What is a cam stud? Can you tell me which part number it is in the parts book? Do you mean that 5/16" double ended threaded rod? The first test I had suggested that you make was to jack the wheels up, engine off, and make sure it turns smoothly, end to end. Since it does not, you need to fix this. Worm bearings, sector clearance (you can flip that turn that sector 180* to get 60 year better surface for the worm to see), bad thrust bearing, etc, need to be addressed. Cam divots, flatted pins, both contribute to the problem when steeing is active. Get some photos posted. Until then it is difficult to judge. Somebody on the board here had a recurring issue with his 730. He had given up on trying to fix it so I offered to look at it. I told him to mail just the steering valve on over, I went through it in less than two hours on a Saturday morning, including cleanup, and shipped it back to him, and it operated fine, first time, and has been since. I replaced the two pins, and stoned out the flats in the cam forms, set the endplay using a good dial indicator, and that was it. I did have to buy a gasket. This post was edited by F-I-T at 05:24:14 07/26/12. [Reply]  [No Email]
ET 07-26-2012 07:19:24 134.179.104.130 Report to Moderator	Re: JD 620 power steering in reply to F-I-T, 07-26-2012 05:09:20   I might have jumped the gun on cam pin. In my minds eye that is the tapered pin you screw in through the allen plug. It ajusts how quik the valve moves. It was replaced in the later systems with a cam set up thats ajusted through the plug on the front of the worm gear bearing housing. [Reply]  [No Email]
F-I-T 07-26-2012 07:24:30 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to ET, 07-26-2012 07:19:24   Quoting Removed, click Modern View to see I think you meant the helix screw, with the tapered end, and yes later on at the black dash change, they went to the plug adjustment in the front. Must have been a popular upgrade, as even my old 70D has the new style. [Reply]  [No Email]
Tim S 07-26-2012 07:33:38 75.60.211.166 Report to Moderator	Re: JD 620 power steering in reply to F-I-T, 07-26-2012 07:24:30   I'm into it now, gonna give it a couple of hours and then get back on New Gens after lunch... [Reply]  [No Email]
Tim S 07-26-2012 11:14:55 75.60.211.166 Report to Moderator	Re: JD 620 power steering in reply to Tim S, 07-26-2012 07:33:38   Okay, I found the 2 Helix pins worn very bad, I cut the ends off 2 new 1/4" drill bits and filed them down to 1/2" long, nice fix there the tapered screw R20913 was worn a bit, they are available for about $45, I cleaned mine up and took the end play down to about .001 (it was about a 1/2") the pressure relief valve was stuck, like Frank suggested, I worked it out and shined it up a bit,,the sector gear was worn a lot, it should be turned 180 like Frank suggested, but I didn't, looked like the complete steering motor would need to come apart to get it up enough to change it. I put it all back together and to my surprise, and satisfaction, it works "decent" far ,far better than before, I think the pins worn to a point, and the R20913 screw backed out was the primary problem with the catching, and the relief valve being stuck was the rest of it..I feel better about sending it home now :>) [Reply]  [No Email]
F-I-T 07-26-2012 12:35:10 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to Tim S, 07-26-2012 11:14:55   Good job! Yeah the sector could have benefitted from a pulling surface, or a couple of bolt holes. As it is, once you have the rotary cylinder disassembled, loosen the bolt on top a turn, and whack it, and the sector pops loose. But if you're that far, time to replace the vane seals and the bottom o-ring. I always though that the old systems worked pretty darn well considering the beating most of them took. An average guy can go through everything on them in a decent full day, if you have a loader or an engine hoist. I remember using the 70 for the first time, and compared to the '48 A, it was unbelievable. [Reply]  [No Email]
Tim S 07-26-2012 13:41:14 75.60.211.166 Report to Moderator	Re: JD 620 power steering in reply to F-I-T, 07-26-2012 12:35:10   They are not even close to as good as a 4020 style, but back then there was a learning process going on. The relief valve was stuck tight,had 2 shims, so I left them in,,didn't have anything to match the test port so was guessing the pressure was ok, the engine is not working against it now and every thing seems good. I don't work on 2 cylinder stuff other than my own very often, but I take them as they come, got a very clean 730D wide front in here too, shifter got out of the stall, rear wheel working out ,needs battery's,, a 2520 split for top shaft O/H, a 7400 for fenders, broken shifter,and AC work...just a work'in them through... [Reply]  [No Email]
F-I-T 07-26-2012 14:08:32 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to Tim S, 07-26-2012 13:41:14   Quoting Removed, click Modern View to see I know they weren't a 4020 system. I've worked on those, too. Just saying that for the time, and 60+ years of neglect, most work pretty well, and can be repaired with not too much in the way of special tools. I sure liked it better than a bolt-on-Behlen. They also didn't have a penchant for puking fluid out from under the steering wheel with little notice. [Reply]  [No Email]
Canadian Ken 07-26-2012 05:51:12 64.235.98.126 Report to Moderator	Re: JD 620 power steering in reply to F-I-T, 07-26-2012 05:09:20   -yes the 5/16" rod- spring compressed length was 1-13/16" - worm end play was .003" -the backlash was .085" -removed shims and used gasket maker to acheive .040" - the bearings and cams looked fine -when I turned the steering worm shaft 90 degrees to remove it as per the manual, it didn't move smoothly - I will post pictures tonight [Reply]  [No Email]
Tim S 07-26-2012 06:33:18 75.60.211.166 Report to Moderator	Re: JD 620 power steering in reply to Canadian Ken, 07-26-2012 05:51:12   It's odd to be talking about this 620 steering,,I have one in the shop doing the same thing,,It came in for brakes and clutch work, the steering was catching and pulling,,the guy said don't worry about it...had it setting out side idling yesterday ( I do this with all the tractors as a bit of 'proving' time) the darn thing sprung a major leak in the steer pump area, fan caught it,big mess,,Darn it. so I pulled the front hood ,removed the pressure line it was in sad shape, installed a new one filled it, ran it as it warmed up the leak came back all over again,,Now closer inspection, the suction pipe is leaking up the inside of the nut,,,I go to get this out and it won't come loose , so I get the air cleaner out of the way and get it to loosen, clean and replace the aluminum washers. Leak is solved now but the oil is heating up quick, the engine is laboring against pump pressure, I'm about to look into it ,,But, I have never had any luck with these,, new Gen steering is no problem to me,,I just never gave these old units any practice time,,part of me wants to put the hood on and ship it,,the Mechanic in me says you can't send anything like this home with out trying...So here I am looking the schematics over and about to jump in... [Reply]  [No Email]
F-I-T 07-26-2012 06:58:40 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to Tim S, 07-26-2012 06:33:18   Sure sounds like a stuck relief valve, which on these is located on the actuator valve, rear surface, lower plug. You can confirm this by inserting a 2000 psi gauge in the new high pressure line and see if the relief valve maintains 1170-1210 psi. My bet is she climbs right over that. Maybe someone added a handful of shims. This post was edited by F-I-T at 06:59:17 07/26/12. [Reply]  [No Email]
Tim S 07-26-2012 07:09:23 75.60.211.166 Report to Moderator	Re: JD 620 power steering in reply to F-I-T, 07-26-2012 06:58:40   That makes sense, and the catching is probably a worn helix and or the pins,,I'm about to open that part up,,gonna give it a couple hours of effort,,then after lunch it's back on New Gens,,where I belong :>) [Reply]  [No Email]
F-I-T 07-26-2012 07:20:56 184.6.240.123 Report to Moderator	Re: JD 620 power steering in reply to Tim S, 07-26-2012 07:09:23   If it's the later unit, black dash or filed upgraded with kit (which even my old 70D has), then there is no helix screw. You set the cam slot gap with the plug and nut in the front. Good luck on it! [Reply]  [No Email]
Canadian Ken 07-26-2012 05:26:49 64.235.98.126 Report to Moderator	Re: JD 620 power steering in reply to F-I-T, 07-26-2012 05:09:20   page 50-6--- part is #24 -F2334R --Steering worm cam rod - SM 2050 manual calls it -"cam spring stud" -just checked at work -not available from Deere -I can take some pictures tonight -the groove is right where the steering worm cam rotates -possibly causing the "catching"? [Reply]  [No Email]
ET 07-26-2012 04:39:01 134.179.104.130 Report to Moderator	Re: JD 620 power steering in reply to Canadian Ken, 07-25-2012 20:49:43   Repace the tapered cam stud. The correct ajustment is right where it's worn. [Reply]  [No Email]
Canadian Ken 07-26-2012 04:45:13 74.114.77.140 Report to Moderator	Re: JD 620 power steering in reply to ET, 07-26-2012 04:39:01   does anyone make this stud? I will check at the Deere dealer I work at today to make sure--not available according to JD Parts -could have subbed # --- Ken [Reply]  [No Email]