I bought a 753 that looked clean and well serviced. All the hydraulics worked fine. I think I might have falled for a common buyer beware problem. I used the loader for about an hour then it started to lose drive / oil pressure it seems. I would put the bucket into some gravel and it would just hang... would not raise bucket or work any hydraulics would not move backward or forward. The pump (not sure if hydraulic pump / hydrastatic pump..??) would make a noise that sounded like it was driving pressure up, bit of squeeling sound sometimes. Then you could move and work hydraulics at slower pace than before. I found that if I kept working it the loader issue got worse. I tried it again the next day and same think happened. I did notice it was low on oil when I got the loader. I am thinking the worst that I need a pump rebuildt but I see that there are two pumps, hydrastatic and hydraulic... What am up for to fix this ?? Any help much appreciated.
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Websterspower
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- Apr 29, 2010
- Messages
- 27
Sounds like a pump belt issue to start... Have you checked the tension/condition of the Belt? That is where I would start
I second that. The drive belt when it wears will allow it to slip and not transfer the power from the engine to the pump.
Thanks guys, I will dive in and see where the pump and belt are located. I thought they were gear driven ? I have to go away for the week so will ponder that till I get home. Is there a good location to get manuals for the 753, I see some on US ebay (I am in Brisbane Australia) Regards Gavan
There is a cover on the left hand side of the engine to expose the belt.
I too am from Brisbane.
OldMachinist may have a manual on PDF format, if you look up his profile and send him an email he can direct you to where to download it (if he has one). The 753G manual i have was bought from the dealer. Even a 751, 763 manual will be very close to yours.
Hi Tazza, Wow from Brisbane, thats great, we are in Ormeau, are you anywhere near there ? I am not sure of the exact model number on the Bobcat, it has the large block letters which I think is mid 90s. I took a very quick look in the engine area before I headed of and found what looked like the pump in the top left hand side towards the front of engine looking from rear. The belt was not super tight so I will tighten it when I get home on weekend and see how I go. I did not notice a cover but I only had a second so will take a look this weekend. I will ping OldMachinist. Thanks so much for your help. I really hope this works as I really like the bobcat. Gavan
I'm from Sheldon/Capalaba. You would be... About half an hour away i would guess.
The pump should be under the seat, its rather large with two levers atached to it. The belt driving it will look like a wide belt with 2 or 3 V belts bonded together. There will be a tensioner that pulls the belt tight, you will need to adjust it.
Ok, I was looking in the wrong place, will take seat out this weekend. If your going past Ormeau any weekend, you should drop in for a beer
You don't need to lift the cab to adjust it. Just remove the cover on the bell housing and possibly the battery for access. Access isn't fun, but can be done, there may be some swearing and lost skin, but you'll get it.Ok, I was looking in the wrong place, will take seat out this weekend. If your going past Ormeau any weekend, you should drop in for a beer
Webster and Tazza, you guys were spot on... The belt had a little bit of play, I tightened it to appropriate tension and put on some belt anti slip to allow for glazing on the belt. The entire bobcat lifted... it had heaps more grunt.... The extra pressure did alter the controls a bit as in the drives are not as even as before from side to side.... But that is not a biggie. Thanks so much guys.... I now have to work out where my hydraulic fluid is going, It seemed to be using about 1L per hour. Yet I cannot see any obvious leaks, there is a little bit on top of drive are but not that much, surely this amount has to be obvious... I had to get some work done by this week so I just sucked it up and kept filling. But soon I have to trace it or by shares in oil refinery
. From posts I saw where people had leaks like this that the leak maybe into drive area, I am going to look at the hydraulics drawings and see what to check... Any ideas welcome
OldMachinist
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- May 24, 2006
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Pull the chaincase fill plug to see if its way overfilled. If one of the inner motor seals is bad the fluid will be filling the chaincase.Webster and Tazza, you guys were spot on... The belt had a little bit of play, I tightened it to appropriate tension and put on some belt anti slip to allow for glazing on the belt. The entire bobcat lifted... it had heaps more grunt.... The extra pressure did alter the controls a bit as in the drives are not as even as before from side to side.... But that is not a biggie. Thanks so much guys.... I now have to work out where my hydraulic fluid is going, It seemed to be using about 1L per hour. Yet I cannot see any obvious leaks, there is a little bit on top of drive are but not that much, surely this amount has to be obvious... I had to get some work done by this week so I just sucked it up and kept filling. But soon I have to trace it or by shares in oil refinery
Thanks Old Machinist, will do that, I have to say thanks on the manual side btw. Are the chaincase seals hard to replace btw ?
They aren't difficult, but they will take some work to access. You need to remove the drive motors. The seals are on the shaft that the drive motors mount to. You drill two holes and screw in self tapping screws and lever the seal out. You then tap a new seal in.
Not hard, but a lot of fiddling and removing things to gain access.
I have found that with the seals replaced all is good, thanks guys.
Tazz , I just punch one hole into the seal with a hammer and an awl that is the perfect size , and use a small dent puller , I put a phillips headed screw into the tip of the dent puller and screw into the hole in the seal , then screw the handle shaft into the tip and it slide hammers right out , saves a lot of time pulling out the drill , extension cord and cranking up the generator for me
You make a very good point, less stuff to clean out too, metal swarf.
