304E2 Thumb/Aux hydraulics not functioning

[Brush]

Hi everyone,


I purchased a 2017 CAT 304E2 late last year from an auction. When I purchased it none of the hydraulics worked. It ended up being a bad hydraulic lockout solenoid and when I replaced that everything has worked fine except the thumb/aux hydraulics.

The machine had two codes on it. A 2211-5(1), and a 2212-5(1). Following the troubleshooting guide in my SIS2GO service manual I used a wire jumper to jump the plug and the code turned to a -6 (FMI 6). This indicates the solenoid is bad, so I replaced both solenoids for the thumb/aux hydraulic circuit.

I started the machine up and I still can't get the thumb to function, nor the aux hydraulic circuit (I have a tilt bucket installed). The next step in troubleshooting is to clear the codes but I don't have a way to do that as far as I know. Would not clearing the codes prevent the functions from working?

I swapped the connectors for the boom pivot solenoids and the thumb/aux solenoids and the joystick can control the boom pivot so it's not an issue with the joystick/wiring as far as I can tell.

I do notice that the bucket will tilt left when I operate some other functions, as if some hydraulic pressure is leaking into the aux lines from other functions (I think mainly bucket curl). I'm not sure why this is happening...

Does anyone have any ideas?

 

[Nige]

I swapped the connectors for the boom pivot solenoids and the thumb/aux solenoids and the joystick can control the boom pivot so it's not an issue with the joystick/wiring as far as I can tell.

The complete control valve assemblies for the boom pivot and the AUX function are the same Part Number. Keep the wiring connectors in their original locations and swap the complete control valves. See what happens then.

a 2017 CAT 304E2

It always helps to post a machine Serial Number. All parts & service information is derived from that.

 

[Nige]

The next step in troubleshooting is to clear the codes but I don't have a way to do that as far as I know. Would not clearing the codes prevent the functions from working?

Are the 2211/2212 Codes still Active.? Check the Codes using the display. If they are still Active that means they cannot be cleared and that the problem is not yet fixed.

If they are no longer Active (Logged in other words) then machine operation will be unaffected and the problem apparently lies elsewhere.

 

[Brush]

Are the 2211/2212 Codes still Active.? Check the Codes using the display. If they are still Active that means they cannot be cleared and that the problem is not yet fixed.

If they are no longer Active (Logged in other words) then machine operation will be unaffected and the problem apparently lies elsewhere.

The machine serial number is ME402200.

As far as I can tell they are just logged now. Honestly, they may have just been logged before I swapped the solenoids out as well.

I was able to get into the service page of the machine but I didn't see a place to clear the codes themselves, perhaps I need access to the CAT software to do that, I'm not sure, but either way I think they are currently inactive.

I've taken a look at the PDF you replied with but I'm not sure where on the machine that part is. I believe all my control valves are sandwiched together into the manifold, but I'm certainly not an expert on hydraulics so I'm not really sure.

 

[Nige]

I was able to get into the service page of the machine but I didn't see a place to clear the codes themselves, perhaps I need access to the CAT software to do that, I'm not sure, but either way I think they are currently inactive.

There isn't. It will require Cat ET to clear any Logged Codes. As mentioned earlier an Active Code cannot be cleared until it has been fixed, this turning it into Logged Code.

If you accessed the Codes via the machine monitor system then the information is right there whether or not any particular Code is Active or Logged. Pay close attention to the screen grab at the top of Page 3.

I've taken a look at the PDF you replied with but I'm not sure where on the machine that part is. I believe all my control valves are sandwiched together into the manifold, but I'm certainly not an expert on hydraulics so I'm not really sure

Sorry that was the wrong arrangement for your machine. The AUX and boom swing valve are part of the main control valve on your model. See #10 and 11 on the illustration below. The block containing the two solenoids is interchangeable.between the two valve sections. It is held on by two Allen bolts. If you do try this be careful not to lose any of the O-Rings (3 per block) that are sandwiched between the block and the valve body.

 

[Brush]

There isn't. It will require Cat ET to clear any Logged Codes. As mentioned earlier an Active Code cannot be cleared until it has been fixed, this turning it into Logged Code.

If you accessed the Codes via the machine monitor system then the information is right there whether or not any particular Code is Active or Logged. Pay close attention to the screen grab at the top of Page 3.


Sorry that was the wrong arrangement for your machine. The AUX and boom swing valve are part of the main control valve on your model. See #10 and 11 on the illustration below. The block containing the two solenoids is interchangeable.between the two valve sections. It is held on by two Allen bolts. If you do try this be careful not to lose any of the O-Rings (3 per block) that are sandwiched between the block and the valve body.

Looks like they're just displaying as logged, so it sounds like it's good as far as the error codes.

I think I will order a couple of those o-rings just in case I lose one before I try to swap those valve blocks. I was worried you were talking about the main control valve, hopefully I won't have to remove/swap those...

Might be a good time for me to drain and put new fluid into the machine if I'm going to be pulling those control valves off. There was enough hydo loss after swapping solenoids so probably best to drain the system as I need to do that anyway.

 

[Brush]

The complete control valve assemblies for the boom pivot and the AUX function are the same Part Number. Keep the wiring connectors in their original locations and swap the complete control valves. See what happens then.

I spent an hour or two yesterday doing this and unfortunately it's only seemed to make things worse.

I realized before I started that it wasn't an ideal time to drain and replace the hydraulic fluid as removing the solenoids has lost quite a bit of fluid each time...so I held off on the drain and fill for now.

I took some time and removed hoses from the entire right side of the hydraulic manifold so I could better access the control valve blocks. I was able to get both the control valves off the machine and swap them without losing any of the o-rings.

I put everything back together, fired the machine up, and have seemingly lost one of my boom swing directions. I can still swing to the right, but it won't swing to the left anymore.

I do seem to have a little bit of actuation of the tilt bucket now as well, but only in one direction and only a very small amount/slow movement. I did have a little movement before I did the swap as well but this seems like perhaps it's slightly more? Hard to say.

Obviously I was hoping the tilt bucket would start working and the boom swing wouldn't work at all, but since the boom swing still works, at least in one direction, I am thinking the control valve blocks aren't the issue...

The only other thing I've noticed is that I can hear something popping open (guessing a solenoid) when I roll the joystick thumb wheel/lever forward...but nothing moves when I do it, I just hear something pop open.

I'm still quite perplexed. Will be giving it some thought for what my next move will be here...

 

[Brush]

I was put in touch with a local equipment shop technician through a coworker and he came out to look at the machine with me this afternoon. We spent a bit of time and he suggested we check the spool valve for the aux circuit.

We took the spool valve out of the boom swing and the aux, at this point he wasn't sure if they were identical or not (they aren't) and moved on to take the valve out of the aux valve block...but it wouldn't budge.

The boom swing spool had come right out, so it was a bit perplexing. Eventually we had to use a hammer bang on a wrench and leverage it out. It took quite a bit of effort to remove it.

The valve itself has a gouge in it (very possibly from the extraction process) and definitely didn't come out easily, so we're thinking this is the root of the issue. Seems to line up with what I've been seeing, some small amount of pressure bleeds through but nothing meaningful.

I'm trying to locate the part number for the spool valve but I'm not sure if you need to purchase the entire valve block assembly or if you can just get the spool valve. I also don't know if there is damage to the valve block assembly or not. I'll dig into it a bit more and call the dealer in the next couple days to see about getting a part number for just the valve itself, but at least for now it seems like I have a lead. We will see what happens!

 

[Nige]

I'm trying to locate the part number for the spool valve

There isn’t one. You have to buy the complete valve section in which the spool lives because each spool is custom-fitted to the valve body in which it lives.

 

[Brush]

There isn’t one. You have to buy the complete valve section in which the spool lives because each spool is custom-fitted to the valve body in which it lives.

That solves that mystery!

I'll probably get one on order tomorrow and hopefully that will sort out the problem. We'll see how fun it is to replace the valve section...

 

[Nige]

Be sure to be sitting down when you ask the price….!!

 

[Brush]

Be sure to be sitting down when you ask the price….!!

Ha, I looked it up, seems like ~$2,100. Not cheap but honestly seems fairly reasonable for the complexity of the part.

The downside is it seems like it's a few to source it. Oh well!

 

[Nige]

I looked it up, seems like ~$2,100. Not cheap but honestly seems fairly reasonable for the complexity of the part.

Calculate the cost of the part as a % of the total current value of the machine……

How about some photos of the valve spool and have you inspected the tunnel that it fits into for nicks/scratches/gouges.?

 

[Brush]

Not the best photo but I think you can see the gouge clear enough. Seems to run along the length of the spool for quite a ways. Not sure what has caused it, but I am guessing there was something stuck in the valve and when remove the spool the gouge was made as we tried to remove it.

It was getting dark/rainy so did not have time to empty the hydraulic fluid out of the valve block and try to get a look in there. I will try to get a borescope and have a look inside.

As much as I would love to have saved the money or had it be something simpler, if $2500 fixes the problem I'm still in this machine far less than it's worth.

 

[Nige]

As much as I would love to have saved the money or had it be something simpler, if $2500 fixes the problem I'm still in this machine far less than it's worth.

OK. At the end of the day you’re the only one who has to be satisfied.

 

[Brush]

OK. At the end of the day you’re the only one who has to be satisfied.

Yeah, I mean, it would have been great for it to be a simple/less expensive fix, but it is what it is.

I am curious what might have gotten stuck and caused the gouge in the spool valve. Hopefully I'll be able to see what happened with a borescope.

 

[Nige]

It must have been a piece of metal to do that amount of damage. The $64k question is where did it come from and are there potentially other pieces like it floating (or getting ready to float) around somewhere.?

The most common source of metal chunks is from hydraulic cylinders. Have you rebuilt any of yours recently.?

 

[Brush]

The problem has been resolved!

We had found the stuck spool valve and I looked around for quite awhile for a used valve to install. I ended up finding a new old stock valve assembly for cheaper than the individual valve I needed, so I purchased that and we got that installed. Added bonus was that it came with the solenoids for hydraulic lockout and hi/low speed, so I also replaced the hi/low speed solenoid at this time.

I decided it would be best to remove the entire valve assembly from the machine rather than try to just swap one valve with the rest still installed, that was definitely the correct move. While the valve was out I also took the opportunity to replace the strainer in the hydraulic tank.

I inspected the hydraulic tank strainer and found a couple small pieces of an o-ring or something rubber.

While re-assembling the machine we did find two o-rings on the aux valve that were missing some small pieces and not in great shape so I ordered those and picked them up the following day.

Once I installed those o-rings I put the last couple of hoses on the machine, went through the process for purging the pump and a couple of the lines, and everything works!

So the issue was the spool valve. Not the cheapest or quickest fix, but it worked for me so I'm happy. The machine has done 20-30 hours of work since getting it running again and it has been fine.

I'm not exactly sure what caused the issue, but I am guessing some sort of debris, perhaps a chunk of o-ring, or perhaps debris from somewhere else got jammed in the spool valve and clogged it up.

Looking at the fluid, it was grey in color in the drain pan, so I am almost wondering if this machine ran a hammer or something similar for too many hours, the hydraulic fluid got hot, an o-ring or something else weakened and got into the system, and things ended up jammed up.

Pump seems to be functioning well. It's not making any noise and all the functions seems to be fine. Hopefully that holds true and all is resolved. Time will tell!

Thanks everyone for the input and assistance!