[eBoyDog]

I think I have problem with the drive on my 446 (the Zebra), in getting the engine running I have been test driving it and it does not behave like my other 446.

When in low and going in a straight line there it slight pauses for a moment then catches and resumes forward motion. Turning left in a tight circle, there is no pause, turing in left in tight circle it more pronouced. going stright up a slight incline the pause is very noticable. No noticable noise when it grabs.

The forward and reverse is proper, In low gear, I can pop the front wheels off the ground with the engine running fast and can lay black marks in reverse (I'm not popping wheelies like the kid on Ytube, this was only for me to diagnois the the issue!)

In hi speed there isn't noticable but I thought for a moment or two it was slightly noticable, I didn't try tight circular turns in hi speed.

Just changed the hydro oil (well it was empty when I got it), 10W40 Rotella.

The travel level doesn't seem to be as smooth as my other 446 as there are spots in putting it in forward or reverse were it seems that it's either retard or full forward/reverse. My other 446 travel is fairly smooth transistion from forward, reverse and inbetween.

There is no noise or metalic sound from the rear end (first thing I thought was it was the rearend gears) the difference between turning left or right made me first think it might be the rearend.

Hydro pump has a slight whine noticable only at idle, ONE thing too that I noticed is that I seem to be unable to put the engine under a load (at idle) when the lift piston is fully extended or retracted if I continue to lower or raise the lift. NOW this is different than a couple days ago when I first got the engine running as the first thing I did was test the lift and I could put the a load on the engine by attempting to raise/lower the lift beyond the max/min.

After a couple of hours of fooling around with it I'm leaning towards either the pump or the spool valve, the spool valve is a concern only because the hydro lines on the lift side were opened to the air for sometime (year, two, who knows) and I have no ideawhat might have gotten into them however when I got it, there was still oil dripping from them so the hydro lines weren't totally dry and when I accidently forgot to hook the return line to the cooler up when I first got the engine running it spit some oil out.

Thoughts, Suggestions or "Well there's your problem!" ?

Thanks!
Wes

 

[Hydriv]

This was a well-used tractor. Begin by rebuilding the travel lever linkage, including replacing the swivel ball joint. Also look for loose or missing bolts that hold the steering crossbar to the frame.

Tell me that 10W40 was a misprint. If not, run with that until you get everything straightened out and then switch to 15/40 or 20/50 if this is just a summer tractor.

 

[eBoyDog]

Opps, Mistype, 15/40 tis was.

 

[tanandorange]

It sounds like the pump is intermittently starving for oil. I wonder if the screen in the hydro tank is partially plugged? Just thinking out loud, but I hope it's that simple.

 

[eBoyDog]

This was a well-used tractor. Begin by rebuilding the travel lever linkage, including replacing the swivel ball joint. Also look for loose or missing bolts that hold the steering crossbar to the frame.

You might be on to something, The crossbar seem solid but something has been modified on the foot rest and instead of the foot rest having the round hole bracket that fits over the rockshaft lift rod, there are metal brackets (similer to L brackets but rough hand made)holding the foot rests in place that are bolted on using one of the crossbar bolts on each side.

Something doesn't seem right in the linkage for the travel control, the lever can't be moved to the full reverse postion (left) but it turns fully to the right for forward movement.

From the few foot rests I have seen, they seem rather solid, I can't imagine why they would missing the underneath part that slips onto the lift rod, if mine were modified, they were cleanly cut or broke off and perhaps even repainted? Is there a style of foot rests that don't slip over the lift arm?

 

[Hydriv]

If you do not possess the correct parts book for the PIN of this tractor, then I suggest that you print out the one in the Tech Section and then do a part-by-part comparison to figure out what is different. If you want it to work like it did when it was new then you have to have the same parts that were used when it was new and those parts have to be in like-new condition.

 

[Rockdog]

Mine seemed solid too until I noticed ALL the support bolts were missing. Was OK until I degreased the whole thing and must have loosened it up cause after that the tractor didnt know what the heck to do when the steering wheel was turned. All the linkages are tight though. The harder it is to turn the spindles the more force will be applied to the steering support at the bottom of the column.

I suggest taking a look underneath the thing while turning the steering wheel (not with the thing running of course) and see whats happening. Take a look at the spring that is supposted to pop the travel level to neutral when the brake pedal is depressed too. Maybe something there is connected improperly.

Regarding the lift cylinder side of things being disconnected I'll bet someone was checking out a problem. I'd also take a look and see if the relief valves APPEAR to be adjusted the same as the ones on your other tractor(s). Couldnt quite make out what you meant regarding loading the engine with the lift cylinder in the full up or down position.

 

[eBoyDog]

Regarding the lift cylinder side of things being disconnected I'll bet someone was checking out a problem. I'd also take a look and see if the relief valves APPEAR to be adjusted the same as the ones on your other tractor(s). Couldnt quite make out what you meant regarding loading the engine with the lift cylinder in the full up or down position.

The lift cylinder lines were open as there are T's on them as the prev owner sold the 3 point hitch that was on the tractor and didn't cap the T's

 

[Snotrocket]

This may or may not be helpful, but when I replaced the TCV valve on my 446 it behaved completely different. Everything worked much smoother and tighter. The float position worked correctly, the retard setting actually seems to slow the tractor down etc.

 

[eBoyDog]

This may or may not be helpful, but when I replaced the TCV valve on my 446 it behaved completely different. Everything worked much smoother and tighter. The float position worked correctly, the retard setting actually seems to slow the tractor down etc.

So do the O rings just wear out? From the diagrams I have seen, there's not much to them other than piston, springs/balls and O rings.

 

[Hydriv]

O-rings can wear out but if they do, the valve leaks oil externally. If you take a valve apart, you will not find any seals or O-rings where the oil is being shunted to the work ports. Depending how well maintained the hydraulic system was, there could be some scoring and wear that would allow the oil to bypass internally, thus affecting performance to a degree but I don't believe your problem would be caused by that.

You have already found what you believe to be Voodoo parts.

I want you to think about the following. Put the travel lever in full reverse and then put it in full forward. Use a measuring tape and check how many inches of movement the end of the travel lever has from full reverse to full forward.

Then measure the total amount of movement in the SPOOL that slides in and out of the travel valve when you put the travel lever from full reverse to full forward.

Here's the point.

The spool moves just a tiny amount by comparison to the lever. Any tiny amount of play in the linkage represents a large amount of lever movement. This is why I stress just how important it is to eliminate all of the wear and tear in the linkage because what looks unimportant to you is very important to how the tractor performs.

 

[Billygoat]

Thanks for another lesson. :trink:

 

[eBoyDog]

I drove it more tonight for about 20 minutes to get the hydro oil warmed up.

Replaced the broken foot rests with a extra pair off a 222 and there was nothing really improved, the cross member is as it should be and the control arms seem to be fine as there is they are right were they are suppose to be will all springs and washers in place firmly.

I think the issue is that someone in the past has adjusted the linkage to spool valve incorrectly or at least as standard goes. I just noticed tonight that in the center postion with the tractor going down a incline it does not free wheel rather it retards and the full forward postion it doesn't fully push the piston in. In reverse, I get a much faster speed compared to full forward. All I need to to do is adjust the linkage and I suspect it will be fine.

I'm starting to feel guilty for what I paid for this 446, I keep thinking the worse and so far that hasn't been true (Did I just jinx myself by saying that?). Check back next week, I suspect I will be full of questions as I'm getting a 18hp Onan for my other 446 this coming weekend.

 

[Hydriv]

Have you noticed how much you are learning about this tractor as a result of these minor glitches?

When owners fail to take care of each small problem in a proper manner when they show up, those small issues begin to add up to the point where ownership is no longer desirable. They often end up selling off a really good tractor that could have ben repaired for peanuts and then they go out and drop more than 2K on some LT with a very limited lifespan. And even worse....that LT isn't capable of doing one tenth of what their old Case GT will do.

So......don't feel the slightest bit guilty. If they really wanted help, then they could have searched the internet and found a Case forum. But they weren't motivated. Now......you have the tractor and you are taking the steps to save it. Had someone else bought it, we might be seeing all the parts on e-Bay by now.

 

[Rockdog]

Arent there o-rings that seal the pressure relief valves to the manifold between the pressure and returns? Dont think a leaky one of these would necessarily cause the problem being described but if it became bad enough your pressure drop accross whatever load you had would decrease.

 

[Rockdog]

Forget last post I was thinking of something else.