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Cat 963c two speed not working moves slow
- Thread starter Sbird
- Start date
pittsburgh cat man
Senior Member
Look at page 73 in senr 1834-11 that should help
pittsburgh cat man
Senior Member
I'm more interested if there is pressure there. I keep wondering if someone did the motors and screwed both motors up the same way. and yes it could be out that far but on both motors i don't know. I'm thinking there has been lots of fingers in this machine The worse thing I found with hystats is people want to turn screws They don't know what it does but say lets try it and see what happens
Yes, and that is what I’m afraid of is maybe everything has been tampered with by someone who didn’t know what they were doing and here we are. I am going right now to put pressure gauges on those ports and see what kind of pressure I have there if any, and I will pull those valves and check them for any obvious problems and report back in a little bit with what I find
Destroke oil pressure for left motor gauge peaked at 1000 psi high idle full forward then dropped back to about 5-600 psi and holds there
pittsburgh cat man
Senior Member
Did you try it in stall at 1700 rpm like the instructions ?
Ok done test exactly as book said this time isolated motor from other by capping crossover line between then disconnected charge pressure line capped it ran hose from charge port on motor to charge pressure nipple on ecm control block warmed hydraulics in sub 20 and put test gauge on forward pressure from sync block get reading from gauge on sync block but nothing from motor control I used the port on the side of motor control just as book shows and 9000 psi gauge and no reading at all at that port the first time I checked earlier was on port on very back motor control but book picture shows the port on the side
pittsburgh cat man
Senior Member
I've been study that since they are telling you that's below your serial number the picture in book only shows one tap on end and one on side. I would go to the one you were in before. From what you said before about pressure dropping makes me think it's trying to work. I also have a question for Cmark do you think its possible someone didn't get pin in port plate I remember having to fuss with them to get it in the right place. and it has the port plate trapped at max angle
So you followed the procedure " Adjustment of the Pressure Override Valve for the Drive Motor", correct.?
This is sending full charge pressure to the motor signal port to make the motor go full destroke all the time, whilst monitoring the destroke pressure. You have basically confirmed what the previous tests showed that the actuator piston isn't getting pressure at the large end.
It's possible the motors have been incorrectly assembled, who knows?
I think at this stage I would be looking at removing the caps from both ends of the actuator and seeing is the actuator piston is physically capable of being moved. Pulling a vacuum on the tank would make this a lot more pleasant.
This is sending full charge pressure to the motor signal port to make the motor go full destroke all the time, whilst monitoring the destroke pressure. You have basically confirmed what the previous tests showed that the actuator piston isn't getting pressure at the large end.
It's possible the motors have been incorrectly assembled, who knows?
I think at this stage I would be looking at removing the caps from both ends of the actuator and seeing is the actuator piston is physically capable of being moved. Pulling a vacuum on the tank would make this a lot more pleasant.
Yes cmark that’s exactly what I did adjustment of the pressure override valve ! Just as book showed I even ran adjustment screw in two turns which book says would turn pressure up 3000 lbs and still no reading on gauge but not sure if gauge is in the right port I used same port on side that picture in book showed I can get reading on the port on the end of motor control as stated earlier but picture in book shows that as wrong port ? That’s what my next move was thinking I’d pull whole block off the end of control and have look see what I might find might even put gauge back on the port at the end and see if anything changed there after adjustment as Pittsburg cat suggested ! Is it possible book picture is wrong and I’m putting gauge in wrong port ?
pittsburgh cat man
Senior Member
I was just thinking, If you pull the bottom off with the over ride valve. If the spool isn't near the bottom it's probably not in port plate right But I can't tell you if you are going to get oil soaked taking it off
Well pulled both ends off and looking at them can’t see anything obvious but what do I know first time looking at this seals and brings look good I can push the actuator back to make destrok but it’s pretty stiff definitely doesn’t move easy but does move
O rings
pittsburgh cat man
Senior Member
Yes they are pretty stiff good bit of pressure on the port plate to seal it are all the holes in end caps lined up with holes on main body?
pittsburgh cat man
Senior Member
I haven't Abandoned you I'm in thinking mode stand by