ford 3400 (3000) 3 point hitch jerky/slow after rebuild

[bobflange]

pbettis, thanks for replying. I did go through all the flow control linkage and replaced all the o-rings and adjusted as per the manual. Some sizes were not included in the lift cover kit so I used standard o-rings in those areas. I made sure the cam follower pin protruded .1" higher from the lift cover than the lift-cover to quadrant cam distance, so I think those adjustments were by the book. First time doing all this for me though, so I'm wondering if I mis-read an adjustment somewhere in the manual, or maybe have an internal leak due to an improper o-ring or something.

My suction screen was in good condition when I got it out, other than needing a cleaning (not too bad though). I had the rear housing hydraulic manifold disconnected (and put a plastic bag over it) before I removed the suction filter pipe inside the rear housing, so I really don't think any debris could have gotten in the pump supply line. Cleaned the metal filter out with brake cleaner, screen first then the pipe after to remove any debris in it.

Other piece of info that might be helpful: the 3ph has held a roughly 800lb weight at full height for over 48 hours now, so everything relating to holding fluid in the piston cylinder must be working correctly.

I found a pump rebuild kit for $25 so I guess that is my next step. Please let me know if you guys think if I'm going about it wrong. Don't want to rebuild the pump if this problem is not likely to be caused by it, especially if the problem would persist and possibly damage the rebuilt pump.

 

[PBettis]

Could you have knocked the spring off attached to the flow control linkage when lowering the assembly down on housing? Would possibly only affect rate of drop though...not sure. Might take an access cover off and see with a mirror and flashlight..? If the suction screen is clear then maybe it is a pump problem. Also there is a check valve (ball and spring assembly) in the accessory cover that may be affecting it. Not exactly sure what that's for because I don't have a shop manual. Please let us know what you find though. Very interested. Sounds like you have more than enough mechanical aptitude as long as you have as much patience!!! Haha... good luck!! These machines will test our patience sometimes! But very rewarding to repair!

 

[bobflange]

The lift cover went on with some difficulty, so there is a chance something went wrong there. It rested on a pivot point on the front right (almost flat but not quite, rocking back and forth as we tried to seat it) right before seating. That being said, we were careful to not let any of the linkage hit anything, I think it was just the two pins on the top of the housing causing issues. If the top or bottom o-ring on the 2" hydraulic fitting sticking out the top of the flow control housing/rear axle housing was pushed off or torn, would it cause this problem? That would be the only likely issue I think we could have had go wrong in reassembly. I think the flow control is working because it will raise more quickly when screwed all the way in then when it is screwed all the way out though.

I did inspect the check valve in the front of the lift cover housing (right under the accessory cover), with the ball and spring, and it seemed in good order. My understanding is that moderates the adjustments on the 3ph when it is under heavy load, to prevent rapid adjustments/jerkiness but I don't know that for sure.

Tomorrow morning I'm going to mount the rear pie weights so I'll start her up and see if anything has changed while I'm at it. Barring a new development, I'll probably put the pump rebuild kit in sometime later this week and then take the lift cover back off if that doesn't improve anything.

 

[Soundguy]

9/16 x 18.. hmm.. sure you are'nt looking for 3/8 straight thread hyds fittings..?

 

[PBettis]

Any idea from the manual how to adjust that check valve we're talking about? Our lift is jerky but possibly because of air in the system. We just recently got everything back together ourselves. I pulled that check valve out and cleaned everything but have no idea how far to run the cap in which puts pressure on the check ball. I tried pulling the cylinder or maybe it's called a spool, ?? out by using a fine thread bolt which is what looks like is used but it didn't budge so i just left it alone. Maybe pressed in (?) Sometimes curiousty can cause problems that weren't there before..haha. any help on that adjustment would be nice. Sorry to ask for help on your thread!

 

[bobflange]

I think the problem is identified. Today I was putting on my rear weights and noticed a small leak puddle on the ground under the right footboard where I had never seen one before. I isolated the leak source down to the ridgid lines right where they run under the right front platform support bracket. I can't see the exact leak point without removing the lines, but it is dry above that area and dry below, and continues leaking from that area after I wipe it. Probably a couple drops an hour rate of leak. This leak was not evident before and has only shown up since I've been leaving the 3ph (with weight) raised at full height over the weekend. I assume this has to be a suction line leak, as I imagine it would be spraying everywhere when running if it was the pressure line, is that a safe assumption? Just out of curiosity, if it is a suction leak, why would I only see it when I have a load on the 3ph? Trying to understand how things work.

Debating my options at this point. Previous owner had a piece of rubber in this area (presumably to protect against vibration wear on the pipes), and I wonder if that had plugged the suction pinhole before, and I moved it slightly when I reassembled, making it not plug the pinhole anymore. Is it possible to patch a suction line with a hose clamp and rubber? Work is backing up while I've been working on this and I wouldn't mind a quick fix to get me through to next summer, then pull things apart in decent weather when work allows. I'm guessing the right thing to do here is pull the lines off and weld up the weak spot, is that how people usually fix this?

Soundguy, to answer your question: I'm not positive of the thread size, but 9/16-18 is what is listed on the new holland online parts manual for that bolt so I'm assuming that's correct. Have you gotten something else that's more common to fit on there?

pbettis: My manual didn't say how to adjust the check valve. I did get mine out with the bolt/washers/block of wood method, it came out very hard but looked to be in good shape. I put it back in and tightened the plug all the way. It felt odd toward the end of the tightening so I pulled it all out again and checked it and everything was still fine. Mine was fully tightened when I took it out and I returned it to that position, if that helps. I did think the manual left something out in this regard though, so you're not alone there.

 

[Soundguy]

9/16-18 sounds very familiar.. i'm thinking it is the straight thread on a 3/8 orb fitting....

 

[bobflange]

Final update: The problem is confirmed and repaired. There was a small leak in the suction line right where the lines make a 90 degree change from horizontal to vertical under the right foot platform. The lines are pretty cramped here and I believe it must have been caused by the pressure and suction lines rubbing on each other combined with dirt from boots falling in that area over the years. I was able to make a functional repair with a piece of rubber and a hose clamp (just dealing with suction so no high pressure issues here), and now everything is working as it should. I'll probably pull the lines off next summer in nice weather and weld it so it's a permanent repair, but this should hold me through the winter I would think.

Had to cycle the 3ph about 10 times after the repair until I saw that it was really working. Must have taken that long to get the air out of the system, so if anyone is having problems like this make sure to run it up and down a bunch of times before giving up on something you've done as having not worked. 3ph raises and lowers in 3-4 seconds now, totally back to normal. Glad to have this finally all solved, it was disappointing to have issues after all the work I did and having everything running correctly now (before snow hits) is a very good feeling. Thanks to everyone for their help and advice.

* Edit: For anyone with similiar symptoms: this was a very, very small hole. The thing couldn't have leaked more than a few drops an hour, yet was absolutely the cause of these problems. I only noticed the issue after leaving the 3ph raised for 2 days straight, not moving the tractor at all in the meantime, and having it over dry dirt with no rain. I'll bet if we had had rain I still wouldn't know what the problem was. Worth knowing that a leak this minor can cause such a noticeable issue.

 

[Soundguy]

you can use a piece of copper water pipe.. sand paper.. flux, and solder it up for a permanent reapir.

WAY easier then welding or brazing.

I've done this MANY times.

used to use a penny.. good fix for rads too...

 

[bobflange]

Wanted to let everyone know I've been using it for two weeks now with no issues. I'll probably get the lines off next summer and fix them correctly, but this patch will almost certainly get me through the winter. Nice to know it wasn't something internal that I did wrong, I didn't want to have to get back into the lift cover.