Brought machine in shop to change a leaky bell housing seal. Pulled the whole asseembly off in one piece and disassembled on floor... pulled the pumps off and one was fine but the other one has a huge crack in the ring that is just behind the gear. I noticed some play in the center gear that drives the 2 pumps. I am getting new bearings and seal.....should the center gear fit the shaft spline tight ? Is this what caused the pump to end to crack? Crazy thing is the machine has been working fine. Not sure how it could with the pump looking like that. I will post some pictures in a little bit. Meanwhile want to find out what made this crack. thanks
Here are some pictures. This is on a hitachi machine. This crack has been here for quite some time. I went ahead and broke off the rest of it and you could tell the cracked metal had a black tarnish to it compared to the piece that I freshly broke off. I just cant believe it would still operate.... in fact we had it in the dirt pit.... where im from we have a very rocky surface.. red clay and rock. We are deep enough to be in what we call "hard pan" . The 951 cat loader is having a hard time ripping on a 20 - 30 % grade. We took excavator down there and ran for several hours and I was very surprised to see a 5' bucket working so well. View attachment 122788 View attachment 122789
Anyone know where I can look to fix problem or could this have been a faulty case ? Im wanting to get this resolved before installing new pump.
You need to try posting those pics again.
Here they are. I talked to the John Deere tech and he said this end of pump is the low pressure side. So he was thinking the crack isnt from hydraulic pressure.
Wow, now that's odd! Wonder if they just got the bearing preload too tight? I know nothing about this particular pump, just guessing. Or possibly a big pressure spike on the other end, but you would think if things shifted much you would lose pressure on the output.
Last person to work on that pump might be able to tell you!
Like the tech said... it should have blew the seal out before cracking metal like this. Strange indeed. I have called several places in US and Canada and ask if they see this failure alot... Most say they dont see this type of failure.
I tried to get some background but the machine came in on a trade and they dont know much about the company who had it. Whats done is done... I would jut like to find out before I drop a $ 1006 in a new case and have it happen again. Looks like someone took a BFG (Big Fricking Hammer) and hit on the opposite end !
Case pressure can do some funny things, I have heard of swing motor cases fracturing from excess case pressure, but I really don't think that's what happened here. For the case to fracture like that, I would normally suspect something went through the gears, side thrusting it, but the gear looks fine, what you can see of it. The only other thing I can think of is shaft thrust, like I said don't know what bearings it has, but it's possible it was assembled too tight and when it got hot the expansion did the damage or possibly pressure spikes on the output, which transmits to the rotating plates, barrel, and piston, so once again excess end thrust and the weakest link failed.
that actually sounds like a pretty good theory.....I thought that bearing came out from other end... I think you can replace seal from shaft end but not the bearing ? So when someone put pump back together and reassembled the End this put more pressure than it could take pushing against the snap ring. That is a weak spot because of the snap ring groove... thats exactly where it cracked.. pretty much half way around. It looks like both ends of the pump where the swash mechanism is have been replaced at one time.
... my theory : that pump already ran with loose bolts, making metal fatigue and failure, a guy just re-tight the bolts and the crack finaly expand with time/case pressure/rapid heat stress, go figure!
Ive seen that kind of destruction from case drain lines having the steel plugs left on after they were repaired. What machine is this on?
The machine is a Hitachi EX 300LC-3. Is there supposed to be case drain lines on this pump ? Do all pumps have vents ? The top plug used for priming has no vent in it either, it has a hole to accept eye bolt for lifting. Steve, If you'll look real close at 2nd picture where the outer ring seats in transmission there is a very small shoulder, about .010" of an inch, the red RTV silicone stops at the shoulder, the pump doesnt actually sit on the part that broke. Thats the first thing I thought when I pulled it off. Looking at it last night, the crack started right between where the two ends of snap ring come together, then it just followed the snap ring groove on around. By all the indicators it sure looks like it came from the inside. Any time something breaks I always like to find out why....not sure Im going to on this one.
Well I can get a reman pump from our local hydraulic company for approxx. $4500 and the factory will set it up for the ex 3000lc-3 and told me its would be plug and play. No tech would need to come out and adjust. Does this sound right ? by the way it has a 1 year written warranty as well.
Sounds about right. We sell ours for $4,000 reman exchange with 1 year warranty To comment on the original issue: Add me to the list of stumped people. I've never seen an HPV-145 do this.
I would believe you have something out internally. Usually if it's a pressure issue, it'll just blow out the seal. If my pic properly loads, shows a linde pump out of my Express bark blower. The unit is mated with a 8 bolt pto. The tank valve broke causing back press are to build and blow out the seal. The repair was a new spline shaft, seal kit, and new bearings. As well, I had the pto rebuilt. Total was $1200. Since they are stackable pumps, am I assuming the opposite end blew out on yours?
Picture to show the whole pump out of truck. Weight is 120 lbs. not an easy removal and install.
I dont think there is a drain on that pump. I think youll find someone will know what he did last just might not tell you. Those vents you talk of are the plugs with the threaded holes on the regulators. You take them out and left them bleed. Sometimes you have to air up the tank to get them to bleed.
Thanks for the pics blowerman... I wish I could get away with a $1200 fix ! I guess it can always be worse though. AndrewC...Got it ..I took the right pump off to inspect the gears in the tranny a couple of days before we discovered the other pumps crack. (Took Right pump off because you have to take pilot off to get Left pump out of housing) When I reassembled I filled tank and then filled the pump at the plug. Pressurizing tank a little to get it to come out at the plug is a good idea !