Weird Hydraulic Issue cat 315CL

[floridamechanic]

Cat 315cl--3644 hours--serial # cjc02070-

 

[funwithfuel]

Wher AA and BB hook up are those pressure sensors?

AA-BB are pressure regulators. They keep you from bogging the engine down. As engine rpm drop, the valve allows more control oil in to destroke the pump keeping rpm in power band. The exact opposite of how you would think.
That servo pressure is a big issue. I don't think I've ever experienced that, but have heard stories.

 

[truecountry]

open door behind cab are there solenoids behind that panel u have to remove panel get someone to operate machine and listen ...its center of machine but panel needs removed ..cat 315 cl have a ground issue with solenoids test the wires open ground ...mine is cjc01986 had bad ground and machine wouldn't move nothing but crank ...pin poke and test the grounds wires see if it sound changes ….send me 250 if it fixs problem ill send u some deer jerky

 

[floridamechanic]

true, ran external ground strap right after i got machine had ground issue with swing/implement solenoid on pump, you are talking about panel fuse box mounted to right?

 

[floridamechanic]

Truecountry thanks for taking time respond, and about the 250? whoever tells me how fix this blank blank unit I will roll around on the ground laughing and send them 500 for a pack of jerky and be tickled be because I got a bargain, man take time to help me I sure take time to help him, been comission mechanic all my life and got paid for what I did,

 

[floridamechanic]

Just adjusted pilot pressure down to 600, still cross feeding and same stick out howl, backed out 1 full turn on pressure regulator, took it off and apart seat and o ring looked fine no trash

 

[Mobiltech]

Going by the videos I hear worn piston slippers causing chatter on one pump in the second video.
On the first video what you are seeing is not that uncommon. As the boom goes down it comes to a point where either the tracks have to move or the stick has to move to release the binding. Try moving the tracks or rolling the bucket and I think you’ll see the boom move also.

 

[funwithfuel]

I see you've been busy. While you had the regulators off, did you consider swapping them? A to B ?
Mobiltech is correct in that sometimes you have to track fwd/rev to allow boom to continue traveling. That said, it looked like you were in soft forgiving material. To me, it sounds like one pump is working its butt off and the other is kinda hanging back, which falls into why, when you touch arm while booming down the thing suddenly comes alive. It just kicks in all of the sudden and with authority.

 

[funwithfuel]

I think you got something limiting your Boom 2 spool. Is it possible to pull the cap and inspect. I know we're all asking a lot. I also realize it's no walk in the park. You may have a centering spring that's come loose and not allowing the spool to return to center. Worth a look. I attached a copy of the schematic . I outlined the flow of oil back to the boom 2. I think the demand from the stick is pushing the logic valve open to allow Boom 2 to join in with Boom 1.
You might also want to look at the small spool in the illustration A , make sure that little shuttle is free. I suspect that is the one that allows one drain oil from Boom 2 to drain off and shift the spool. if the drain is blocked the spool cant shift.

 

[floridamechanic]

I think your right, put teeth in soft sand and try stick out it has way way less power than it has always had, did not think about swapping just changed the wires, Mobiltech what are piston slippers? Is that the loose cup on end of rod that slides in/out of cylinder on pump? Just curious, Funwithfuel do you have a picture location for us old folks on the valve you want me to pull? Been on dozer all day, brain dead, will pull boom2 first? Or swap regulators first?

 

[funwithfuel]

I sure dont. Sorry. I should think the ports would be identified by alpha numeric characters cast into the valve body. aL2 should be the spool identifier. I have clipped a section from the material Nige posted. It gives a pretty clear description of what is happening where. The smaller spool or passage as it is referred to should be adjacent to the spool cap . Should just be a couple screws to remove . Remove the end cap/plug to access spool. You may not even need to remove, you may be able to just shift it side to side. Bottom line, make sure its not bound up.
In the second image , it shows the basic components of a piston pump. What Mobiltech is referring to are called out as piston shoes, I believe. Everyone calls em slippers. #1 point of failure of a piston pump.

 

[funwithfuel]

I'm 90% sure the highlighted housing in the image is where you want to look. In the past, I have encountered where fittings in a body have scarred the spool to where it eventually seized. A little grinding, a little polishing of the spool and all was right with the world. I hope this shows something.

 

[floridamechanic]

yep that is what i thought, thanks, may be back off dozer in time tomorrow to start looking at valves, should I swap regulators first ? or just get into valves? And yes what you sent will get me started thanks

 

[funwithfuel]

I'd look at the spool in the small housing first. Pull spool caps and check centering springs second. Regulators third. Be as clean and careful as humanly possible.

 

[funwithfuel]

When you move spools, oil will come out if your implements are not completely neutralized. Be extremely careful please.

 

[floridamechanic]

yea always kill engine key back on, move everything bleed off pressure thanks

 

[John C.]

Take the cap off the hydraulic reservoir as well before you bleed off the pressure in the circuits.

 

[funwithfuel]

9 psi can make quite a mess.

 

[John C.]

Both those and the radiator caps never held any pressure. It might say nine but I've yet to find a used one that held more than five on a Cat excavator. Most I've tested were around two. Even so you will stay cleaner by taking it off.

 

[floridamechanic]

I am in on that lol thanks.