Undid a pilot hydraulic line and lost forward movement.

[antpoo]

Hello all,

I undid a hydraulic line connecting to my left joystick (Cat 287b) as I attempted to learn how to pull it apart to replace likely broken oring leak. Well after it squirted oil I decided to just tighten it back up but now I do not have forward movement.

Does this mean I have a lonely airlock now or something?

If so, how can I re pressurise?

Thank you.

 

[antpoo]

Also, I was trying to undo the hoses to learn how to access the (resolver) because it appears that my hydraulic leak is coming from a likely broken oring. If I were to undo all the hydraulic hoses does the joystick control Valve separate so I can replace orings or is it a more technical procedure? Thanks will post photo.

 

[antpoo]

Leak from valve? I believe it is called a resolver. I replaced all the plungers no problem, But the leak coming from inside valve block/resolver.

 

[Cmark]

I would say that an airlock is unlikely.

When a person makes the mistake of loosening an ORFS fitting whilst under pressure, it isn't unusual for the O ring to become dislodged. Then in haste, the fitting is re-tightened and the O ring gets cut.

Magic 8 ball. Is it possible that a piece of O ring is jamming something up in the valve?

"Signs point to yes"

Thanks magic 8 ball.

 

[antpoo]

I would say that an airlock is unlikely.

When a person makes the mistake of loosening an ORFS fitting whilst under pressure, it isn't unusual for the O ring to become dislodged. Then in haste, the fitting is re-tightened and the O ring gets cut.

Magic 8 ball. Is it possible that a piece of O ring is jamming something up in the valve?

"Signs point to yes"

Thanks magic 8 ball.

 

[antpoo]

Hello thanks for reply.

I posted photo. I simply undid the hose in direct middle of photo. Machine was off. I merely cracked loose the hexagon nut/valve that the hose screws into but decided against undoing and simply screwed hose back on. 10 mins later I started machine but no forward movement.

Does oring break still seem likely in that instance? And if so, will undoing all hoses and trying to clear oring solve or likely make all controls lose function?

 

[antpoo]

Hello thanks for reply.

I posted photo. I simply undid the hose in direct middle of photo. Machine was off. I merely cracked loose the hexagon nut/valve that the hose screws into but decided against undoing and simply screwed hose back on. 10 mins later I started machine but no forward movement.

Does oring break still seem likely in that instance? And if so, will undoing all hoses and trying to clear oring solve or likely make all controls lose function?

Ok I see , the nut I cracked loose was ORFS fitting.

 

[skata]

Take the hose off and inspect it

 

[Cmark]

Hello thanks for reply.

I posted photo. I simply undid the hose in direct middle of photo. Machine was off. I merely cracked loose the hexagon nut/valve that the hose screws into but decided against undoing and simply screwed hose back on. 10 mins later I started machine but no forward movement.

Does oring break still seem likely in that instance? And if so, will undoing all hoses and trying to clear oring solve or likely make all controls lose function?

I suggest you remove the hose you loosened and see if a piece of the O ring is missing. If so, you need to work out if that particular line is flowing to or from the pilot control valve and go chasing the missing piece from there. It seems too much of a coincidence that the problem arose right after you loosened the fitting.

 

[antpoo]

I removed hose and the ORFS fitting it attaches too. Oring looked perfect, everything clean and good.

I’m now starting to wonder if it was my joystick plunger seal repair from the day before, I replaced all the plunger seals. however I did manage to drive it forward 3m after the repair and park machine, the loss of forward movement happened after I undid the hydraulic hose, and one of the resolver Allen key screws.

Will pull apart joystick and recheck plunger seal springs.

 

[Arny L]

I have an ASV with exact Cat pilot controls as yours, and I'm positive those are ORB fittings, the only O ring is on the fitting that screws into the main body, up against the threads, the hose seals against it with a 37 degree flare, Much like brake line. Not 100 percent positive though. The large hose in your picture is the return line to tank, and if you don't cap it when undun it will continue to drain your tank and make a mess. I don't think removing a hose should cause a problem like your describing. I think its more about your previous repair. Just my 2 cents

 

[antpoo]

Ok thank you for your 2 cents. Have you undone hoses before and separated the upper left side joystick assembly from the lower section that hoses plug into?

I need to fix a leak in there, I’m certain it’s an o-ring and I merely need to undo hoses and separate the two halves of joystick assembly and repair, but I can’t be 100% certain there aren’t any intricate internal components and I would hate to lose all functionality if there were and i upset any of them.

 

[Arny L]

I only swapped entire unit, never pulled apart, but I know you can. You better make sure you can get the o rings before pulling apart. Mark all your hoses and corresponding fittings carefully. I used colored zip ties. You should cap all hoses and fittings to prevent contamination, especially the return line which will leak forever, because your lower than tank. There are some threads on here that address this repair, you'll have to go searching,

 

[antpoo]

Ok no worries. Yeah I’m familiar with case drains. I’ve also narrowed down my forward problem. I located a spring that wasn’t on the plunger but must have bounced out unnoticed into the hole in the pic. I returned it to the front plunger but alas still no forward movement.

The last shot is that somehow I mixed the springs up. It’s the last possible cause, and the springs are different sizes. As I did one plunger at a time I don’t see how I could f**k that up, but I did lose the spring so I’m going with somehow I managed to f**k it up.

 

[antpoo]

Nope , still no joy, everything assembled according to schematic but front plunger unresponsive and left plunger very slow.

Rear and right plungers work perfect. Reverse and right turn.

Hopefully someone can help.

 

[Cmark]

It sounds like you've worked out which hoses do what. Can you learn anything by switching say, left and right or fwd and rev to see if the fault is in the pilot valve?

 

[antpoo]

Has been disaster trying to separate the the upper joystick control valve assembly from the lower. I’ve lost 40litres of oil, will prolly lose the rest overnight. Tank is higher than the valve so once a hose undone it just leaks everywhere. Cap didn’t do any good.

Disheartened.

 

[Arny L]

You cant use plastic cap plugs, you need proper metal cap fittings, (Amazon) that matches your fittings. When tightened they will not leak.

 

[antpoo]

Well looks like not too many people out there experienced with this stuff. Nonetheless I persist to learn the hard way and will post as I go along.

I separated the resolver from the upper joystick valve/plunger assembly. 1 oring was damaged as I suspected, and it was the cause of this horrible drama.

Quoted $130 by Westrac for the 6 Orings lol! I’ll be looking elsewhere to source.

The resolver is removed by a simple Allen key bolt at bottom of resolver, but you need to prize it apart with a big blade screwdriver.

It looks simple to look at, but I think somewhere inside the resolver holes are ball bearing check valves that are malfunctioning and stopping signal pressure from reaching main drive spool.

There are Allen key screws that surround the resolver and I can see that they can restrict or allow flow on the 4 plunger holes. I’m not sure what their position is meant to be so I tightened them full which totally blocks flow. That’s the way the were originally set.

I pulled the plungers and upper valves apart 13 times, and thoroughly cleaned, I am convinced the upper assembly valve is fine and it’s that damned resolver. Just priced a new one at $560 which is better than I was expecting.

I wish I new how to get inside the resolver and check the check valves.

 

[antpoo]

I have just realised thanks to this diagram that the 4 Allen key screw things on the side of ball resolver valve are actually seats for the ball valve. I am not sure how important they are to be in any particular position, I screwed them tight.