Draft-control valve replacement fixes all kinds of things

[MikeOConnor]

Another update -- and a question. In my enthusiasm, now that the new valve was making everything work so well, I decided to replace the *filter* in the draft-control circuit. Argh! My sluggish low-pressure troubles returned. So just for the heck of it I unscrewed the *valve* enough to relieve the pressure on the circuit and screwed it back in again. Presto! Snappy performance restored. So I'm wondering -- does anybody have an opinion as to whether that circuit needs to be bled when a new filter is put in? And, if it does, what the right way to do it is? I have a feeling that replacing the valve may not have been what did it, but rather that I accidentally bled an air pocket out of the circuit and *that's* what actually fixed the problem. That would sure be a cheaper fix for folks with that trouble.

 

[RegL]

Another update -- and a question. In my enthusiasm, now that the new valve was making everything work so well, I decided to replace the *filter* in the draft-control circuit. Argh! My sluggish low-pressure troubles returned. So just for the heck of it I unscrewed the *valve* enough to relieve the pressure on the circuit and screwed it back in again. Presto! Snappy performance restored. So I'm wondering -- does anybody have an opinion as to whether that circuit needs to be bled when a new filter is put in? And, if it does, what the right way to do it is? I have a feeling that replacing the valve may not have been what did it, but rather that I accidentally bled an air pocket out of the circuit and *that's* what actually fixed the problem. That would sure be a cheaper fix for folks with that trouble.

Where's the filter for draft control circuit. Don't think I have one on the pt1430.

 

[MikeOConnor]

Bah. I was just testing you. It's not the filter for the draft control circuit. It's the charging valve filter. Sorry about that -- draft control, seat leveling and brake tender circuits all go through that charging valve in one way or another. Here's a picture of the draft control valve and the charging valve filter right below it. All roads lead to the charging valve.

 

[woodlandfarms]

Confused. I have this filter system as well. I guess they dropped it in 2010. Anyway... What valve did you undo?

 

[MikeOConnor]

Hi Carl,

Interesting that they dropped that filter in 2010. I can see why -- the maze of circuits that relies on that charging valve is unbelievably complicated. Anything that simplifies that would be a Good Thing.

Anyway, the valve I'm talking about is the draft-control valve. That's the one that controls how much the draft control lifts the mower deck. The valve is on the assembly at the top of that picture just upthread (there are two gizmos on the top of that assembly, the one on the left with a knurled knob and a locking ring is the valve). That's also the valve that is pictured in the third post of this thread. I didn't completely remove it, just unscrewed it enough to let a little oil leak out and then screwed it back in.

My evolving theory is that with all those different circuits going in and out of the charging valve, it's possible that air bubbles get in there and goof things up.

One of the intriguing things is that little nipple that shows up in the newer picture - directly below the draft-control valve assembly. I wonder if that's a bleeding point, kinda like the one we use to bleed the main intake line when we change our filters. I'll try to remember to call Terry and ask him about that after the holiday. Does anybody else know what that nipple is for? That would be a much easier way to bleed that circuit than pulling the valve - especially if it could be done without running the tractor. Kinda like bleeding the air out of a radiator back in the old days -- just open up that nipple, wait for air to escape and a little dribble of oil to come out, replace the nipple.

 

[ponytug]

Ask Terry?

All the best,

Peter

 

[MikeOConnor]

Yup, that's the plan fersure. Mostly curious if others have really dug into all the plumbing that goes in and out of that charging valve. I've replaced it a half-dozen times and I'm starting to think that it's possible that I've been maintaining all the other stuff incorrectly for all these years. I wish I'd kept a detailed maintenance log so I could go back and look up when I replaced the charging valve filter the first time. It may just be that all the blown seals and leaks were caused by incorrectly changing the filter. That would definitely fall in the "let no good deed go unpunished" category.

 

[PTWannaHave]

As I prepare for a PT-1430 purchase (my 1st machine with hydraulics), this is the kind of story that rattles my nerves...! :worried:

 

[woodlandfarms]

Owning a pt is not for the feint of heart. Either you know a good mechanic or you are not afraid to get greasy. If both are an issue you should not get a pt. This said, the machine is worth the aggravation. And in terms of aggravation in the end not a lot of us have issues. My machine was abused. Really abused. Caught on fire abused. Rotted outdoors abused. The guy I bought it from put a ton of money in fixing it up. Did a great job. But certain systems just had issues. And then I got it and I abuse equipment. Or should I say I work my machine to the limit. I take good care of it but this week I am on a 35 degree slope pulling out well over 100 trees that are over 50 ft then grinding the stumps. Couldn't do this with a regular tractor nor could I do it as quick. I feel you are making a good decision on the 1430.

 

[MikeOConnor]

I talked to Terry this morning.

He confirmed something Carl mentioned up thread, which is that they dropped that charging-valve filter in 2010 -- the same time they switched to the new version of the draft-control valve that they put in. So I think all this rigamarole probably doesn't apply to a new 1430.

He says that replacing the filter shouldn't require bleeding, but that if I ever DO want to bleed those circuits I should crack the port on the bottom of the charging valve. Sometimes, that's just a port, sometimes there's a hose on it. Just crack it and then tighten it back up again (essentially the same thing I did, except I did it at the draft-control valve).

Finally, he said that the nipple I highlighted in the picture is NOT the place to bleed it.

That concludes my report.