3-Point Hitch 4300 HST 3PT slow / barely working

[arkvet]

Like the title of the thread suggests... I'm having some trouble with the 3pt hitch. I want to apologize for not having all the right terminology in place but I don't have my manual in front of me. The problem with it has been slowly developing. This past summer I noticed the rockshaft lever seemed to be getting stiffer. Also trying to adjust the implement to a precise height was getting more and more difficult. For instance when I would try to hook something up I would try to make subtle adjustments with the lever and it wasn't happening. All or none it seemed. After a while it seemed that the stiffness was increasing and the overall lift height was decreasing (not lifting as high). I attempted to go through the repair manual steps and removed the seat and removed some hydraulic lines (per the manual) to check a small inline wire mesh filter/valve? (For the life of me I can't remember the name of it). When I removed the filter the bottom was "blown out"??? Therefor it wasn't serving it's purpose. I assumed that it had probably once been heavily clogged and maybe the pressure caused the bottom to break open. Due to time constraints and the lack of a replacement part (couldn't really find one that I knew was correct) I put everything back together and continued to use the tractor.

At the same time I did drain and replace the hydraulic fluid and cleaned the main hydraulic filter on the tractor. No noticeable improvement with that change.

Since that time the problem had been mostly ignored until most recently when the 3pt has really gotten bad to where it will barely lift anything. I hate to admit neglect on my part but its' simply the truth. When I used the manual to go in and "clean the valve/filter there weren't instructions on what to do if the filter was broken... only on how to clean it.

Can anyone give me an idea of what my current problem(s) is/are. Thanks

 

[arkvet]

I've done some deep searching on the subject and it appears I'm not the only one that has had the problem. Apparently the broken part is called the rockshaft filter (inlet filter). This was a problem noted on the earlier 4000 series tractors and they later changed the location of the filter to just above the PTO housing to make it simpler to pull and clean. I've read in some really old threads where they make a retrofit kit for the earlier models that routes the filter back above the pto housing (like the later models) rather than simply replacing the original (hard to get to) filter.

If I can locate the correct kit/parts I don't think I'd have any issue making that retrofit.

My bigger concern is the damage that has been done to the position control valve since this filter has not been doing it's job. I'm sure the reason for my poor 3pt performance has been the screen parts and debris that has traveled into the control valve.

For anyone that has seen this problem... Do I need to go ahead and assume replacement of the control valve will be necessary and if not... how can I tell?

Any diagrams and part numbers would be much appreciated.

Thanks!

 

[Henri88]

I wish I could help you but this is way over my league. Hang in there, I'm sure someone will chime in soon.

 

[jd670]

Can u post any pics of the filter to give an idea of what your looking at?

 

[arkvet]

http://www.tractorbynet.com/forums/...ating/11733-torn-rockshaft-filter-4300-a.html

This is a link to a thread over 10 years old. The OP's attached picture is exactly what happened to my 4300 filter screen. All of the research I've done suggests that the problem is that the pieces of the metal screen have likely gotten stuck in the rockshaft control valve. I talked to my JD dealer yesterday and he was very vaguely familiar with issues of this nature. He said it looked like there used to be a kit that was produced to retrofit onto the 4000 series tractors to move the filter back to the easier to access location. It wasn't sold as a kit any longer but he's supposed to piece it together for me... Fingers crossed that I don't end up with a box of parts that aren't what I'm looking for.

Anyway, he couldn't really answer the question regarding what the health of that control valve likely is, considering it has sucked in some metal screen pieces. The control valve is $500 so I'm trying to get some answers with what I'm probably looking at before beginning the breakdown. My FEL still works fine and I hate to completely take my tractor out of service for an extended period of time. I just want to be prepared before starting the dis-assembly.

 

[arkvet]

Another thing is I don't want to buy a new $500 control valve if a $2 O-ring may be the culprit. I was hoping someone familiar with this part of the tractor could shed some light on the possible probs/fixes beforehand.

 

[footer200]

You do not have to replace or update that filter it is just the power beyond line from the loader valve to the rock shaft control valve. Anything that filter is going to catch has already passed through the loader valve. My 2 cents. The hydraulic system has a filter screen and filter In it. I added 3 rear spool valves to the rear of my 4300 and they are just plumbed in that line between the loader valve and the Rock shaft control valve. You can remove that complete steel line and just use hydraulic hose in its place. As for the control valve itself you should be able to take it apart see if anything is stuck in it (pieces of old filter) cleaning it out and even get rebuilt parts for it.

 

[footer200]

You could even install a remote spin on style hydraulic fluid filter using hydraulic hose in that path if you were concerned.

 

[arkvet]

You do not have to replace or update that filter it is just the power beyond line from the loader valve to the rock shaft control valve. Anything that filter is going to catch has already passed through the loader valve. My 2 cents. The hydraulic system has a filter screen and filter In it. I added 3 rear spool valves to the rear of my 4300 and they are just plumbed in that line between the loader valve and the Rock shaft control valve. You can remove that complete steel line and just use hydraulic hose in its place. As for the control valve itself you should be able to take it apart see if anything is stuck in it (pieces of old filter) cleaning it out and even get rebuilt parts for it.

excellent. Thanks! That's what I was looking for. To me the filter seemed redundant... and how ironic that the stupid filter caused a problem that the filter was intended to prevent... Just plain stupid.

So as it stands I am going to break it down and pop out the mesh screen that is broken and toss it in the trash. I'll then remove the control valve and see if I can visually find the problem before spending $500 on a new one.

One technical question remaining: The Rockshaft lever is extremely difficult to move up and down. Can this be tied directly to the problem with the valve or do I likely have a concurrent problem with the "tension disc" that I've seen mentioned in other threads.

Thanks again.

 

[footer200]

Stiffness could be bits of screen jamming this spool valve itself (tearing O-rings), or where the lever goes across the top of the axle housing it could be binding or getting stiff. Is or has the tractor ever been used in salty conditions? Depending how when where the tractor is used, mud, dirt and crud can build up in the area under the seat where the shaft goes across. I am NOT at my computer right now but search for 4300 rebuild by defrug ( not a hundred percent if that's the right spelling) ? And he has lots of great pictures of linkage and control valve taken apart.