well my smallest excavator has been foaming in the hydraulic tanks for the last few days, let it sit 30 minutes or so and the foam would disappear and machine would function fine. Weirdest part was it was an intermittent problem, well today after running for about 30 minutes there was a loud pop and the joysticks jumpped. Now no hydraulic functions at all, bobcat is comming in the morning to pick up, I was able to drag it out of the spot it was in and out to the road with a second machine but was unable to get it loaded on my trailer. Am I over thinking this or am I probably due for a hydraulic pump?
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Expensive Pop?
- Thread starter wrc
- Start date
pafarmer
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Loud pops are never a good thing...sounds like a new pump is in order plus a complete system flush plus whatever else went on it....not good at all....could be as simple as a hydro line too but .good luck on it either way...is it still under warranty ? Hope so because things can very expensive quick when a hydro pump goes...you were sucking air, that's what the foaming was all about....stop if this happens is your best option ...let us know what they find on it...what model is the digger ?
no pa farmer its not under warranty its on an older 331c. I knew stopping when foaming was the best option. I did stop took it to the shop searched high and low for air leaks couldnt find any so pressured the tank with an air compressor and towel, after i did that there was no more foaming, weird i know however i took it out and ran it for about an hour was running perfectly then POP what ever it was showed up in a big way.
You could get lucky and it's just the pump drive coupler, not sure what that consists of on that little guy.
If there's a suction strainer in the tank that could have been plugging up also which increases the likelihood of sucking air.
Sounds like it was sucking air at a hose connection or possibly the pump seal, pressurizing the tank must have sealed it up a bit?
If there's a suction strainer in the tank that could have been plugging up also which increases the likelihood of sucking air.
Sounds like it was sucking air at a hose connection or possibly the pump seal, pressurizing the tank must have sealed it up a bit?
pafarmer
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I do the same thing ...sometimes it's just the way it is....hope for the best and go for it.....I'm an idiot too when it comes to just get done and to hell with the consequences....worry about that later. Getting done what I started seems to be the priority....funny stuff really...it's a guy thing....
pafarmer
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You are one lucky SOB ! Good for you ....if it were me I would need to a new machine because it would be so bad it wouldn't make sense to fix it, but I have bad luck...good to hear and thanks for sharing the good news...
ya I'm hoping it was just the coupler, bobcat says that there is no way to "bench test" my pump I asked them. seems strange to me but I'm not mechanical person, well at least I don't consider my self one I do ok with simple parts swapping but not do much on rebuilding. The most complex mechanical work I ever did was to swap out an automatic transmission in a f450 with a 5 speed manual. second to that is a straight foward motor swap. but I figured a dealer could test a pump on the bench. so I'm hoping like he11 that I don't gotta buy a new pump after they reseal and install the old one.
kshansen
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Guess that would depend on if they have the tooling to do the test. I'm sure the company that built the pump can test one without having a Bobcat sitting there to install in in! If they are going to "reseal" the pump I would expect them to be able to see if there was anything wrong internally. Seems to me strange for a couples to snap by its self.
Have they looked into the foaming problem?
Rentalstop
Well-Known Member
Some Bobcat dealers are not as good as others. I guess this could be said for any brand. I needed the hydraulic drive motor rebuilt on a brush mower (leaking seals). Called Bobcat in Columbus, told me to bring the entire unit in, they could rebuild it but had to install it to test it. Wanted big money. Called Leppo in Wooster. Yup, send it in we can rebuild it and bench test it. Half the cost of the Columbus dealer and didn't have to leave my shop. Columbus once told me they couldn't cut the Bob-tach pivots off and replace, told my to call a certified welder. Leppo said they do them all the time.
Hope you have a dealer that has a clue. Good luck.
Hope you have a dealer that has a clue. Good luck.
rondig
Senior Member
I rebuild pumps all the time .test everyone of em before I send them out....mind you I have a test bench and a hydraulic shop. These couplers are NOT oil friendly ...the rubber get eaten up almost instantly. With a seal problem...usually problem stays all the time....same with strainer. Strainer problem would be worse on start up and get better with hot oil. I have seen the suction hoses fall part in side and cause suction issues. Cavitation is BAD. Hopefully coupler failed due to wear....cause If it sheared you still have pump problems. I would test pump whole they change seals tell them to send it out. Any hydraulic shop can test them with bench.
kshansen
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Ok, guess I was thinking about the steel splined couplers like the ones in say a Tyrone Gear pump and some others.
well got a call again yesterday, they rebuild the pump and installed it back into the machine. The tech that did the work said everything looked good but the pump will only produce 3gpm....need a new pump, this is starting to get expensive now. I am really up set that they went to the trouble of rebuilding the pump at my expense only to tell me it needs replacing. ...GURRR