Cat 330cl hydro pump failure I need help

cat0330cvdky00377
Back story (I was not involved with the work)...
Machine was wining (cavitation) bad at all times (low or high RPM, loaded or no load). Pump was pulled and got new barrels and pistons and resealed, no change. Called in the cat house and mechanic made some piping changes (from service bulletin), no change. He suggested the pump had a bad housing. Pump was sent out to an independent hydro shop that claimed they had a good housing and would swap out the good new parts ($8,000) and bench test pump for $10,000 (could have got a cat remand for $17,000 in the beginning). After the pump was put in the cat tech came out and set all the pressures and machine ran fine for about 80 Hrs. (8 months). The machine has a jaw crusher tool and is only used to break large chunks of concrete for a concrete recycling yard. All the sudden it lost all hydraulic functions in the middle of the yard and that is when I got the call. The guys there are good with a wrench but they thought it was electrical and I do a good bit of that kind of work for them.

After a couple of electrical checks I didn't have gauges with me so pulled the pilot test port no pressure (flow). Could hear some growling from pump so pulled the aux pump cover, gears are turning (thinking maybe drive plate). So thought we lost the pilot pump and since it is inside the bell housing (thank you cat, rexroth) we pulled the drive axles and swing gear and drug the dead machine over to the side of the yard and off came the pump again. When I went to pull the pilot pump this is when I figured they had got screwed on the pump deal. The paint was still on the bolts and the rest of the pump had not bin painted also found the pilot pump shaft was sheared. Pulled the pilot pump apart and had chunks of metal jammed in gears. Pulled the main pump apart and found chipped teeth on the drive and driven shaft gears of rotating groups. The tank, suction screen, and main hydraulic filter had no sign of medal in them and on the suggestion of the cat guy I pulled the hydraulic cooler and no sign there as well. Here is where it gets really weird.

Since the pilot pump pulls from the bottom of the main pump housing I figured the spin on filters would be full of crap. They where bone dry, no oil at all had gone to or though them in 80 hours?

I know I'm going to get flamed for this but all I have is the parts book for this machine. I called cat and they quoted me $1,100 for the service book and I'm not sure it will help me sort out what I suspect is a piping foul up.

They have already got a cat reman pump for the machine but I just don't know what to do next?

Can you find some details of what the Cat tech did..? At least if you can narrow it down regarding which lines system he was working on (pumps, suction, return, etc, etc) - "Called in the cat house and mechanic made some piping changes (from service bulletin),"

SENR5450 is the Cat Publication you need. Here's one on eBay for $300............. https://www.ebay.com/c/1609311046

There should be a suction screen in the tank to check. Have you checked the case drain filter? Maybe that is the spin on you mentioned. How about the return filters in the tank.

I would also suggest opening up the one of the main cases and checking on the the piston and barrel assembly. The other thought is the suction hose connecting the reservoir to the main pump. Noisy pumps usually indicate air in the stream or suction problems.

The thought on the pilot pump drive gears being broken kind of sends my thoughts to the pump not being assembled properly in the first place. The machine would not have worked if the pilot pump had never pumped any oil from day one. I would also be plenty suspicious of what piping changes were needed on a 2002 model machine.

^ What JohnC said X100 I have seen pump systems with a common suction fail something on the main pump and get sucked into a pilot/implement pump. At 80 hours I would suggest you send it back to the people that rebuilt the pump as it should be warrantied. I, as a self employed tech, wouldn't touch this with a 10 foot pole.

I had this happen on a 330 turns out there was contamination in the big supply line had to pull line off and clean it out. I wont make that mistake again

Dave Neubert said:

I had this happen on a 330 turns out there was contamination in the big supply line had to pull line off and clean it out. I wont make that mistake again

Click to expand...

Removing all the accumulated contamination could prove time-consuming, not to say expensive if even the smallest quantity is lying in a corner somewhere and gets overlooked.

Consider doing a dialysis/kidney loop on the complete implement hydraulic system after reasembly until the ISO Code for the oil is no higher than 18/15 - 16/13 would be better still.

Thanks for the reply's...
@ Nige, I will ask about that service bulletin and see if there is a connection. The link you gave me took me to " cat caterpillar 215 excavator 95z 96l service shop manual" , thanks for looking but I don't think that will help, will it?
@JC, I did tear down the main pump and that is were I saw the chipped drive teeth, the barrels and piston looked OK but showed way more wear than 80 hours. The suction screen, tank, and main return filter showed no sign of contamination. There are 3 other filters, a small aluminum cup with screen that I think maybe the case drain for drive motors (it did have a small, tiny bit of fine metallic partials), a small spin on that I think is the pilot filter (dry), and a larger spin on that I think is for the tool line (dry)
@ Vetech63, The shop that did the pump will not help and I had nothing to do with that so will not trash talk them on the net. When I talked to my hydo supply guy he told me to run as well, just to many cooks in the kitchen on this one but this customer has dragged me into the deep end of the pool before and we have a long relationship and I'm not afraid to get a black eye on this one.
@ Dave N, I would guess most of us have learned more from our mistakes than our successes.

Sorry, should've written RENR5450 ............

Try this link - https://www.ebay.com/c/1609311046

Nige,
That link did give this option https://www.ebay.com/itm/331555239993 I sent the seller a message asking if it will cover the hydraulic system for my serial number.
Thanks

I drained the hydro tank into a 55 gal. drum thinking about sending in a sample for testing. Maybe just pump off the bottom of drum, what do you think?

What does the back of the piston retain plate look like? Is it real shiny where the slipper shoes ride?

John C. said:

What does the back of the piston retain plate look like? Is it real shiny where the slipper shoes ride?

Click to expand...

Just where it ball of piston is captured the rest of the plate was dull. I should have taken more pictures before I put it back together to get credit for the core, the customer got a cat reman.

Pilot filter has a relief in the filer head, 3 connections, 1 from pilot pump, 1 to pilot manifold and 1 to tank.
Small aluminium canister is the case drain for the main pump and has 2 connections , one goes straight into the tank and the other should connect to the main pump case on the top near the bellhousing.
Then you have a larger spinon with 2 connections, that's case drain for swing, travel and fan motors, this goes straight into the tank also.

it is impossible for these to be dry if the hoses are correct.

Per Eriksson said:

Pilot filter has a relief in the filer head, 3 connections, 1 from pilot pump, 1 to pilot manifold and 1 to tank.
Small aluminium canister is the case drain for the main pump and has 2 connections , one goes straight into the tank and the other should connect to the main pump case on the top near the bellhousing.
Then you have a larger spinon with 2 connections, that's case drain for swing, travel and fan motors, this goes straight into the tank also.

it is impossible for these to be dry if the hoses are correct.

Click to expand...

Thanks Eriksson,
Need to think about this, Is it possible to siphon the spin on filters by draining the tank?
I will look at the hoses (had put telephone wire on all fittings) to check what you gave me and see if that is the way it is piped. My fear is that some lines may have bin crossed by another "cook in the kitchen". I can't help but think that the pilot pump pushed some trash into the system before locking up, just trying to figure out where to look systematically and not chase my tail.

Just want to update this thread,
Well I ended up cleaning up pilot and control valves and cleaned out the cooler (did find some trash but nothing alarming) but did not pull everything hydraulic apart to clean. Did some creative plumbing and flushed out valve bodies with a small filter pump rig. Put it all back together and gave it a go. Had low main pressure and found that main relief valve was bad (scar on seat) and replaced it. Only have 20 hours on it since the repair and everything is operating normally (except the coupler is slow). After a pump failure like this I guess nobody will trust this machine 100% but I sure feel better at this point.

Also should add that the customer got a replacement machine from the cat dealer (used) and it is having hydraulic problems that the dealer is working on so the jaw is back on the old machine. This time of year is slow but as the hours add up on her the confidence will go up as well. Boy I hope I didn't jinx myself by posting this.... now my phone may start ringing.

Did a 250 hour service (oil change) last week and pulled hydo filters and cut them open. They were relativity clean. The old girl is still making small rock out of big ones with good power. Getting closer to a happy out come on this one. Just thought I would share that with you all since so many pump failures like this turn into a nightmare.

thanks for the update!