Cat 320B LL Forestry Swing Machine Hyd Lockout

[BrianGrenier]

It wouldn't be too far afield to think that's part of the main relief valve...say it broke the shoulder then stuck in the port...

but I think I reviewed that as I pulled it out after sleeping on it, thinking that might have happened. I could pull it out another time as mobiltech said it only takes 5 minutes

 

[BrianGrenier]

21mm+-

 

[Mobiltech]

Here is a picture of the main check valves. If one of them fails you would notice pressure loss when using single pump functions .
I think it might be a bearing race from your auxiliary pump drive .

 

[Mobiltech]

In this picture you posted you would have to pull the bottom left pump which is driven off the main pump by the adapter in my last post .

 

[BrianGrenier]

Is that 'bearing race' from auxiliary pump drive maybe in the
' Drive GP - auxiliary group'? (above)

Or would it maybe be in the group for the pvg075? (below)

 

[TVA]

Didn’t really see the radius on the phone until I got to big screen of my PC! And your CAD drawing shows it as taper.
Yes, looks like inner race of ball bearing!

 

[Mobiltech]

The oil from that pg075 pump won’t be going to the main relief valve.
The main cat pumps draw oil from the housing so it is posibble for a failed aux bearing to get picked up and sent to the main relief. Seems unlikely it would do that without causing more damage but still possible.

If you want to look at the main control check valves that’s easy to do. There are 2 Allen head plugs just left of the main relief on the front face of the valve body with a check valve and spring under each one. Yet another 5 minute job to eliminate them too.

 

[newguy2k3]

You found a piece in the main relief valve and a piece in the return filter?

Think about oil flow here. If it was a bearing race from something in a pump the shrapnel would be in the case drain filter. To get a piece into the main relief it would have to bypass the case drain filter, suction screen and make it through the pump without damaging anything. The pieces would have to be from one of the pistons, barrel or further down the line. I'd look at the check valves in the main control valve at the main relief. Seems like it could fit and could end up going through a circuit and winding up in the return filter.

 

[Mobiltech]

Main pump doesn’t have a case drain filter. Case drain on the main pump is part of supply oil to main pump and pilot pump.

 

[TVA]

I think everyone can agree that the easiest thing is checking check valves, and if they are fine - move on to something else?!

 

[BrianGrenier]

Have an Answer!

I took a fourth look at the main relief valve...I think the pictures
should show that the part is the shoulder of an older and replaced main relief. What do you think?

 

[BrianGrenier]

I didn't check the main control check valves under the Allens ( I checked the valves to the left)..after re-reading the advice, I wonder if I should still pull. Cat is running good.

 

[BrianGrenier]

Not all is perfect. For example, climbing a hill, the machine will stall... this is with medium high engine speed. I can hear the pumps on and the excessive load on the engine.

 

[John Shipp]

Hello Brian, when climbing a hill, why would you run engine "medium high"? Wouldn't wide open throttle would be the normal choice?

Good luck getting this fixed, your perseverance will chase down this fault, like the look of that machine. All the best.

 

[BrianGrenier]

Hello Brian, when climbing a hill, why would you run engine "medium high"? Wouldn't wide open throttle would be the normal choice?

What is the preferred RPM to be running something like this?... often I don't run wide open... especially at first with that forestry head which took a bit to get good at, lol!

I was walking some stumps and slash down instead of burning I just like to mound it and smooth it over. With all the back and forth I was not full throttle and when climbing the pile, she just stalled, so being cautious and careful, I'm hoping for your advice.

Maybe the PRV is set correctly?
[/Quote]

Good luck getting this fixed, your perseverance will chase down this fault, like the look of that machine. All the best.

Thanks!!
Here's another picture, over 70,000 lbs, 45' long
She can use some new decals but runs strong

 

[John C.]

Forestry heads are designed to run the best production at high idle. In addition, in order to get load sensing out of the pump you have to be at number 10 on the throttle dial.

 

[John Shipp]

Does a 320b have engine rpm read out in the monitor somewhere? Handbook may list high idle rpm setting 10, possibly 2100rpm on a "B"? (1850rpm on a "C"?) Running hydraulic excavator, run at specified high idle for everything except cold morning warm up (check handbook), also possibly very delicate grading around something precious could use position 7-8, everything else including running on/off lowbed= high idle. IMHO.

Love that picture, post as many as you like

 

[CatKC]

Does a 320b have engine rpm read out in the monitor somewhere?

The engine RPM can be displayed in Service Mode -Group 10 Item 12.
If you don't know how to enter Service Mode - A video on how :
“www.youtube.com/watch?v=yTKIMSH_kI8”

 

[newguy2k3]

Main pump doesn’t have a case drain filter. Case drain on the main pump is part of supply oil to main pump and pilot pump.

The hydraulic schematic shows one just like every other 300 series cat excavator I've ever seen.

 

[Mobiltech]

320b case drain is internal and pilot pump also draws from case. You must be thinking of C and later models.