I'm still having lift and tilt problems on my 763 1998. I took the HYD. block off and noticed the main regulator allen screw was backed all the way out. I wish I would have know about this before taking it off. Anyway I clean it up and painted it. Put it back on and turned the screw all the way in. Put new aw46 fluid in. Fired it up and tried the bucket. I now have tilt down working enough to lift the tires off the ground barley. I drained fluid down and happened to notice very very small metal particles in oil. Not sure if ti was there before ( I'm thinking it was). I removed the gear pump. Took it all apart and notice the internal wall of the pump (only on one side) was worn about 10 thousandth's of an inch. Is this enough to drop psi preventing from lifting? I adjusted the belt to the 3 oclock postion. tried again. Same. While I had the block off I decided to drill and tap the fitting comming out of the pump so I could check psi. I guess I should do that next. What is the likley hood this pump is bad? Jeff
pump question?
- Thread starter 763-NJ
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That sort of wear in the pump could be the issue. Check the pressure like you were going to, you should get about 2,600 PSI when you dead head one of your hydraulic functions. Tilting the bucket all the way back will do the job.
Are you sure the relief is not damaged? the springs are still ok? and when you wound the screw in, there was good resistance?
Are you sure the relief is not damaged? the springs are still ok? and when you wound the screw in, there was good resistance?
I have a gauge comming tomorrow so I'll know more tomorrow. The relief did have some tension. I did not remove it. I might just get one. I only have tilt down but does not dead head. Do I have to drain all the fluid to get the relief out?
It will just un-screw, but oil will start leaking out the hole. If you stick a cap in it, it will help slow it down some.
Get a gauge on it first and see what it says. Then mess with the relief to ensure it's in good shape. If it is still low, it could be the pump wear.
OK, I put a gauge in at the pump outlet fitting here are the results. At idle with deadheading the cylinder 1600 psi At high rpms deadheading the cylinder 3500 psi I can only get alittle movement on tilt down to get these readings. Will not tilt back or lift. It tilts down but only enough to lift the tire slightly off the ground. Not really deadheading the ram. Any ideas?
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That's with the regulator cranked all the way in.
OldMachinist
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Relief valve on the 763 get set to 3000-3100 psi so it sounds like your pump is putting out enough pressure.
OldMachinist
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You may want to take the tilt cylinder apart to make sure the piston nut hasn't come loose or the seals are bad.
I don't have lift either so I'm guessing that I don't have much flow and I'm bypassing fluid through the pump.
doing a pressure test is not always enough ,as it is only 1/2 of the senerio ---- do a flow test at idle and then full throtlle and look at the free flow verses the flow at working pressure as you close off the needle valve ----- I think that a 763 was about 17 gpm
I checked what I think is a psi tap on the lower ram of the bucket. It's an allen screw. I did not get any psi there.
That pressure seems ok to me too, even if the flow is down, you should still have power to lift the machine with the bucket, it just may be slower.
It's almost as if the lift lock is engaged preventing it fron giving any flow to the lift and tilt rams.
Is there anyway to bypass or check the lock? All lights on BICS, BICS solenoid magnetized. With the bucket off I though I would get more movement. Didn't happen. Fustrated.
Not sure if you can by-pass it or not. There is a solenoid running to the lockout block, if you run power into the solenoid, it should un-lock the lift/tilt function. With the engine off, if you run 12V into the solenoid, you should be able to hear a slight click, it is very faint, but it will be there if it's working.
My model has the lock out block bolted to the face of the main block. I do have power to it and it does magnetized the coil. Can't tell if it clicks. When I try to lift the bucket the left ram moves rapidly about an inch the stops like it locked out. Right ram does not move. I'm going to replace pump and take the block apart and check it out.
Well this is weird. I took the block off today and removed the three stems one for BICS lock and the two AUX. ones. They are cutoff right after the main threads. I know someone tried to fix this before I got it. I guess they were trying to get it to unlock. I guess I should take the whole thing apart to see what else they did. My question would be on the BICS one. Being that it is cut off would that allow the system to bypass and work? Or not work? Maybe something else wasn't right and they tried this.
Yikes.... That is very wrong, i thought having it like this would keep oil flowing at all times, which it shouldn't be doing..... I think the previous owner had a secret machine butcher job on the side.
I don't believe that would allow it to be bypassed and work, i think it would cause more problems than it would fix....
If the lockout stem was cut, it may allow for the lift and tilt to work all the time, but not the aux hydraulics as it would be fighting against its self all the time.
