Serial number is 508185. On the bottom of the main control valve there is a section called the propel flow combine valve. Machine will break the cover to the spool in about 10 minutes of run time. Owners have put 2 of them on and I was there for the third yesterday. From what I understand it provides extra flow when tracking and operating boom/bucket. It has a pilot line going into the cover and pushes the spool into the mcv and my theory is that when it returns to the original position it slams the cap and breaks it. Nothing on the spool looks wrong and the parts breakdown shows a blurry something that resembles a washer but of course it’s not there and is obsolete. The washer looked like it would add an extra little bit of cushion before the spool could hit cap. I wish I had gotten a pic of the spool but I didn’t. Has anyone seen this before? I did get a pic of the cap. All of them have broken identically.
If it was on a crane I would say that the spool/ valve is bad, Is there supposed to be a washer/ shoulder on the other side that limits travel toward this cap, and its worn out, allowing the spool to overtravel? In other words, I don't think the problem would be in the cap, but in what is hitting the cap. Because it shouldn't ever hit the cap. Are there any marks inside the cap from it getting hit? The "washer" probably just centers the spool on the spring. so when it gets "returned" is the pressure causing the spoll to get crooked and wedging the spring and the spool sideways?
Here is a clearer breakdown of the propel flow combiner valve . It’s #1 in the screenshot below. .
That’s correct. He one thing that is different is #2. It looks to be a duplicate of #5. I was thinking along the same lines as crane operator. my thought is that the small pilot like line feeding the cap pushes the spool upwards and when it return, it is slamming into the cap and breaking it. I didn’t find any evidence marks on the cap where it had hit but it wasn’t on the machine for more than 20 minutes and they had already thrown out the original cap. I did modify a washer to fit between the cap and the #6 washer thing thinking it would force the spring to absorb the hit before it hit the cap but that didn’t work either. there is no complaint about performance or noise, etc. it just breaks the cap and then leaks.
Not to be a smart a** , but are you possibly confusing the propel flow combiner valve for the auxiliary function flow combiner valve. The auxiliary function flow combiner is on the bottom of the 5 spool side of the control valve. It is shown as #1 in the screenshot below. .
I’m going to call it the propel flow combiner valve. #6 and #8 are the evidence. The auxiliary function flow combiner valve is on the opposite side of the mcv on this machine.