Cat 303.5e sticky hydraulics

[TVA]

I had never seen insides of that pump before - but for some reason I don’t think inner spring supposed to be shorter the outer. There is no spring guide going through, and no way to insure that inner spring will go correctly around the “snout” of that seat.
Can you look closely to the picture of the manual you found before, and see if the springs supposed to be the same lengths?

From what o see - the inner spring is broken on the bottom, and broken piece wound inside of the remaining part. Or that’s just oil looking like that.

Or the outer spring supposed to be pre compressed to the length of the inner spring when installed.

 

[Aaron.ampcon]

Where this one go, on that picture?View attachment 233816View attachment 233817View attachment 233816

That one goes inside the hole which you see on the one that has the o ring and yes that one looks fine o ring is fine

 

[Aaron.ampcon]

I had never seen insides of that pump before - but for some reason I don’t think inner spring supposed to be shorter the outer. There is no spring guide going through, and no way to insure that inner spring will go correctly around the “snout” of that seat.
Can you look closely to the picture of the manual you found before, and see if the springs supposed to be the same lengths?

From what o see - the inner spring is broken on the bottom, and broken piece wound inside of the remaining part. Or that’s just oil looking like that.
View attachment 233831

It's just the oil that has it looking like that, it's not broken. From the picture I had found it's not clear to see the length of both springs.

 

[Aaron.ampcon]

The only valve shown inside the inlet section is the unloader valve.

I would take apart the one with the 2 socket heads and hex in the middle and inspect.

 

[TVA]

That one goes inside the hole which you see on the one that has the o ring and yes that one looks fine o ring is fine

Can you circle it on this picture?

 

[TVA]

It's just the oil that has it looking like that, it's not broken. From the picture I had found it's not clear to see the length of both springs.

Just see if outer spring gets pre compressed when installed in to pumps body.
If that inner spring is weaker then supposed to - it is a reason the torque control kicks in earlier then supposed to.

 

[Aaron.ampcon]

View attachment 233837
Can you circle it on this picture?
View attachment 233837

It looks to be in this area

 

[Aaron.ampcon]

Just see if outer spring gets pre compressed when installed in to pumps body.
If that inner spring is weaker then supposed to - it is a reason the torque control kicks in earlier then supposed to.

Yes the spring gets some compression when installing front cover plate of pump.

 

[TVA]

Yes the spring gets some compression when installing front cover plate of pump.

Can you check weather it gets compressed to the point where inner spring touches both seats?

 

[TVA]

It looks to be in this area

Everything in red color indicates hollow cavities filled with pump supply pressure oil. But these schematics are wrong all the time - so no big deal!
Looks like that little one is the one that actually do the pushing on that bigger one. Because that gland with o ring is stationary.

 

[TVA]

Did you ever had main relief valve off and inspected?
I know you were going to, and tried to
adjust it with no results.

 

[Nige]

No specifications for those two springs, unfortunately. So even measuring free length wouldn't tell you anything.

In case of any doubt that the springs could possibly be the root cause of the problem, or even a contributing factor, I'd vote to fit new ones just in case.

 

[TVA]

No specifications for those two springs, unfortunately. So even measuring free length wouldn't tell you anything.

In case of any doubt that the springs could possibly be the root cause of the problem, or even a contributing factor, I'd vote to fit new ones just in case.

Thanks Nige!
I don’t think you can buy those separate from the pump. Lots of these rebuilding companies use aftermarket or manufacture their own parts for rebuilding. But those are wear parts like valve plates, pistons and slippers and piston blocks.

I don’t think anyone have these for sale, unless they have very high failure rates!

If no damage will be found anywhere, beside already discovered, Aaron going to
have to find someone with differential pressure gauges to find out weather the problem caused by drop of LS margin pressure or Torque limiter maul functions. Just to get an idea in which direction we would have to “dig”!

 

[TVA]

I guess if nothing else Aaron is going to
try to play with this torque control to find the happy medium between bogging engine down on combined operations and having decent power and speed. If instructions would not be found or impossible to follow.

But there’s still unloader valve left to
Inspect, and I still didn’t see the port side of the piston block.

 

[TVA]

Aaron, inspect also smaller servo piston and bore, that the one that next to these springs, not the fatter one on the bottom.

 

[TVA]

Anyway 280-4448 and 280-4449 is the part numbers.

Don’t go buy an airbag though!
Unless you want to lift your pick up!

 

[Nige]

Same numbers I came up with. About $150 the pair.

 

[TVA]

Same numbers I came up with. About $150 the pair.

Airbags?!

 

[Aaron.ampcon]

Did you ever had main relief valve off and inspected?
I know you were going to, and tried to
adjust it with no results.

Yes I did have it off and everything inside seems fine no broken springs or anything

 

[Aaron.ampcon]

Aaron, inspect also smaller servo piston and bore, that the one that next to these springs, not the fatter one on the bottom.

Is this the one that is on top of these springs which contacts with the swash plate and pushes against these springs?