Recently purchased a Gehl 4625. It has a leak coming from the Pump Drive Coupling, specifically around the Pump Adapter. This is where the engine connects to the tandem hydrostatic pump. There is a small slot at the bottom of the Pump Adapter (maybe 1/8" x 3/8") leaking oil and another leak on the forward side of the Pump Adapter. It leaks maybe 1/4 cup of oil/day when not running. The engine oil had been recently changed, so I can't determine whether it's hydraulic or engine oil that is leaking. Anyone who can shed light on the subject will be appreciated.
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I can't tell from color since the oil was recently changed - just before I bot the machine, and it's identical color right now to the hydraulic. I'm considering changing oil in my dlesel pickup and putting the dirty oil in the skidsteer just long enough to see if it's the engine oil.
. If its engine oil, what would you suspect is the source of the leak given the location?If it was engine oil, the most likely spot for it to leak back there is the rear main seal. Can you get your hand back there to see where its wet at all? If its on the pump, it soulds like the main shaft seal, if its on the fly wheel, its possibly the rear main.I can't tell from color since the oil was recently changed - just before I bot the machine, and it's identical color right now to the hydraulic. I'm considering changing oil in my dlesel pickup and putting the dirty oil in the skidsteer just long enough to see if it's the engine oil.
I would not recommend putting dirty oil in the engine, as you say its loosing about 1/4 cup a day, run it for a while and keep checking the oil levels. Which ever one is dropping is the source of the leak. Easy and won't risk any damage to your engine.
OK, made some progress tonight in that I am sure it's hydraulic fluid and not engine oil which is leaking. It's leaking where the tandem hydraulic pump connects to the engine pump adapter, which is between the tandem hydraulic pump and the engine. Tazza, I took your advice and did not put dirty oil in the Kubota engine, but drained out enough to determine that the engine oil is darker than the hydraulic oil. So now that I know it's coming from the tandem pump what do I do next? From what I've seen online those pumps are really expensive. But, the darn thing works fine; just has a leak from somewhere.
I'd bet its just a seal. If its from the engine side, its probably the main shaft seal. The problem is getting it out. I have never worked on one of these machines before.
Hope you're right Tazza. Those pumps are $1500 as rebuilds! I have a shop manual. It gives a very good description of how to get the pump out. If it's a seal is that something I can do or would you recommend taking to a shop. I usually do things myself if possible. On another note is the whole idea of a "tandem pump" that it can run simultaneously run at different flow rates in order to accommodate each side of the skidsteer? Thanks for all your help Tazza. btw I was in the Navy in the early 80's and have been to Broome, Perth and Sidney. Nice country.
As long as you keep the area clean, i can't see why you couldn't have a go. I believe they call it a tandem pump as there should be two seperate pumps bolted together, one for one side, one for the other.
$1500 for a rebuild isn't actually that bad. New, a pump for a bobcat is over 8k. Still, for the issue you have, i can't see it costing anywhere near $1500.
Hopefully the pump can even stay in place. Is there room to remove the spool? You may loose a lot of oil, but its best that it flows out and takes any grime with it.
.au is generally a nice place, mid summer it does get a bit warm, thankfully not for too long though.
Sorry ignore me, no spool. You will still loose oil, but i find that it flushes the area. Just get something ready to contain it or it may make a large mess on the shop floor.
That's a good idea; leave hoses connected and try and disconnect pump from motor and pull the pump forward enough to get a new seal on?
You can try that, but not sure if you will have enough space. Removing the motor may be easier than you think. This should give you the space you need.
I went ahead and pulled the tandem pump out of the skid steer. Now that I can get a look everything, the main shaft seal does not appear to be leaking. However it might be under pressure. However, I did notice something on the bottom of the pump - see picture -- that was leaking oil. I'm not sure what it is, but wonder if it's some kind of relief plug. It was essentially like as washer with an O-Ring that was covered by the plate in the left part of the picture. The plate is rather light metal. Also notice the plate has rust on the inner side; this is because the plate had been bent and was not complete flush with the pump body. That's not some sort of frost plug is it, in case you get water in the oil?? http://i892.photobucket.com/albums/ac126/johntbartels/photo-2.jpg
It does look to be some sort of plug. It looks dry, so i assume it was not leaking there.
Did you see any areas that were wetter than others? It may help locate the leak.
We will find out what's wrong, I took it to a local hydraulic shop. They will tear apart, clean and give me a repair estimate for $40.00. I did read that it's a port for a auxilary pump. That port is on the bottom of the pump; it was caked in dirt/oil/moisture. The moisture that caused the rust probably caused that plate to give in and the seal failed. It's a relatively flimsy plate.
When removing the plate I twisted off one of the cap screws (it was rusty) so I took to shop to have that drilled out and have a pressure test done. The shop said they won't do anything until it gets cleaned up as any dirt in the pump could cause problems. I would normally take an easy out and remove the screw myself, but that thing's worth quite a few $$$ and I didn't want to risk making the situation worse.
I lost quite a bit of fluid in removal - probably 3+ gallons. Will I have to bleed the system? If so how?
$40 doesn't sound too bad for them to examine it and no doubt give it a good clean.
I try and avoid ezy outs, they are a lot stronger than my trusty drill bits are. If one was to break, i'd be pretty well screwed. I try and drill the screws out and run a tap down it to chaase the threads that removes the bits that are left.
I didn't think the $40 was too bad either. But it is going to takee some time. The guy said he had six 100 ton jacks used to lift railcars that had to be done first. I saw one. The piston was huge! Now, once I get this pump back and installed, will I have to bleed the hydraulic system? The shop manual, which by the way I really am glad I bot, said I didn't need to drain hydraulic system; so I didn't. But, it probably lost 3 gallon during the removal - yes it was one heck of a mess. So now I"m wondering what I'll have to do as far as bleeding, if it's necessary. I have an old IH 966 tractor. On that I have to bleed the loader hoses when ever I replace a hose. But, I'm not sure how I'd bleed this skidsteer.
You shouldn't have to bleed it. These systems are not like brakes, air will get out over time. Depending on how airated the oil gets, it may take a few days.
What i do is run it, drive it around lift and tilt avoiding bottoming out the cylinders, shut it down over night. This allows the bubbles in the tank to settls out. Do the same the next day, and the next till it runs well.
There is no avoiding loosing oil, i figure while its pouring out, it will not allow any crud in to cause damage.
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I generally try to pump the oil out through the front couplers first, but you will always spill some when you open a system up. Any updates on the fix?
Wonder what could be done to keep moisture and dirt away from the plugs. If it freeze where you are, that wet mud is going to push with a tremendous force and should be cleaned out prior to freeze up. Even just sitting and rusting is not vary good.
Ken