Gentlemen,
I just got done rebuilding a dual hydraulic valve off of a 970. It was stuck. Tractor sat for years.
Everything went fine, but I decided to do a quick check with shop air before I put it back on. Everything
seemed fine until I put the upper spool in to full retract. In that position, while putting air to the
input side of the valve, I noticed air blowing to sump when it should not. After looking much closer at that
spool, it seems to be traveling in the casting to the point of slightly uncovering a groove. You can see the
edge of the spool land in the photo. You can also see where it looks like that part of the casting is slightly
"shorter" than the same part of the casting around the other spool (which works fine). They both are fine in
extend.
First tought was it is overtravelling, but this position is right where the detent plunger sits in the groove.
It cannot really overtravel anyhow, as the head is the stop.
Is this a casting flaw, or, is it possible some remote valves where setup to have 1 remote friendly to 1-way cylinders?
This would do it, as there would be no (or very limited) pressure at retract.
I can't say how this valve behaved when last used, as I was about 28 years younger when I last ran this tractor.
Any thoughts? Casting numer is in one of the photos. Oddly (unless this is not the valve number) this does not
show up in the parts system.
Thanks!
Darren
I just got done rebuilding a dual hydraulic valve off of a 970. It was stuck. Tractor sat for years.
Everything went fine, but I decided to do a quick check with shop air before I put it back on. Everything
seemed fine until I put the upper spool in to full retract. In that position, while putting air to the
input side of the valve, I noticed air blowing to sump when it should not. After looking much closer at that
spool, it seems to be traveling in the casting to the point of slightly uncovering a groove. You can see the
edge of the spool land in the photo. You can also see where it looks like that part of the casting is slightly
"shorter" than the same part of the casting around the other spool (which works fine). They both are fine in
extend.
First tought was it is overtravelling, but this position is right where the detent plunger sits in the groove.
It cannot really overtravel anyhow, as the head is the stop.
Is this a casting flaw, or, is it possible some remote valves where setup to have 1 remote friendly to 1-way cylinders?
This would do it, as there would be no (or very limited) pressure at retract.
I can't say how this valve behaved when last used, as I was about 28 years younger when I last ran this tractor.
Any thoughts? Casting numer is in one of the photos. Oddly (unless this is not the valve number) this does not
show up in the parts system.
Thanks!
Darren