pittsburgh cat man
Senior Member
Ok just checking if they had updated controllers and skipped a step yours are still org ones for machine
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Cat 963c two speed not working moves slow
- Thread starter Sbird
- Start date
The only other small line I see on motors is coming in the center of the motor not on the motor control ? There are signal hoses on control and a crossover line between two motors that’s all I see for small lines
pittsburgh cat man
Senior Member
I was looking at post 198 and it is not the same as the one Nige sent us for the 963 I'm positive it is a 953c
You're right. It is 953. I was looking in the wrong folder. Let me dig out the correct one.
JAJ
Senior Member
Hi guys you are all going to great lengths to get to the bottom of the drama for the OP… and OP is doing a great job of the troubleshooting at his end. It is a showcase of the forum at its finest! It’s also very fascinating reading
I have never driven or worked on a track loader, so I may be way off with this but I have just been reading through the spec brochure for this model machine to understand some more about the machine in question. I just spotted some interesting points and it leads to my question. It states that the Electronic Hydrostatic Control (EHC) automatically adjusts machine speed to give priority to the equipment hydraulic system, while the hydrostatic system uses the rest of the power available. Does both systems use the same pump and if so can the problem actually be in the hydraulic system somewhere (as it has priority) and the symptoms showing up in the hydrostatic system due to not enough flow?
I have never driven or worked on a track loader, so I may be way off with this but I have just been reading through the spec brochure for this model machine to understand some more about the machine in question. I just spotted some interesting points and it leads to my question. It states that the Electronic Hydrostatic Control (EHC) automatically adjusts machine speed to give priority to the equipment hydraulic system, while the hydrostatic system uses the rest of the power available. Does both systems use the same pump and if so can the problem actually be in the hydraulic system somewhere (as it has priority) and the symptoms showing up in the hydrostatic system due to not enough flow?
Here's the 963. It's actually even simpler. The pressure to destroke the port plates comes from the drive loop. If you can confirm that the motors are seeing signal pressure by plugging a gauge into the end of the hose, then I don't see how it can be anything other than a motor problem.
But two motors with the same fault? I don't like those odds.
But two motors with the same fault? I don't like those odds.
JAJ
Senior Member
Re my above post…. It was a stupid question, I have just re read the pdf data uploaded earlier in the thread.
Seperate implement pump is shown, should have read it properly my apologies.
Two seperate pumps and motors both with same fault doesn’t seem likely unless they are just worn out from natural causes, is this a possibility?
What is the rpm drop limit that the ecm starts reducing travel speed? Could someone have played with parameters like this via ET?
Cmark, I remember when I spoke to you about getting ET some time ago that you warned me (very rightfully so!!!) that someone can cause a lot of problems to a machine with “Dealer Level ET” if they don’t know what they are doing. If you get my drift, thinking about the old owner replacing the ecm himself. Just a thought
Seperate implement pump is shown, should have read it properly my apologies.
Two seperate pumps and motors both with same fault doesn’t seem likely unless they are just worn out from natural causes, is this a possibility?
What is the rpm drop limit that the ecm starts reducing travel speed? Could someone have played with parameters like this via ET?
Cmark, I remember when I spoke to you about getting ET some time ago that you warned me (very rightfully so!!!) that someone can cause a lot of problems to a machine with “Dealer Level ET” if they don’t know what they are doing. If you get my drift, thinking about the old owner replacing the ecm himself. Just a thought
That’s what I thought I will put a gauge on signal hoses right at motor and confirm the reading the computer shows is accurate I keep reading that motors won’t destroke until the pumps fully stroke so I’m guessing that if signal pressure is good then that has to mean pumps are fully stroked right ? Or am I missing something ?
pittsburgh cat man
Senior Member
Don't get discouraged from what you have said there has been a lot of part changing trying to fix the problem. As far as pumps being at max stroke I would say that it is a real good chance they are. We just need to study and think awhile ,We'll get it figured out
Ok had short hose made with fittings for gage and unhooked signal lines from motors and installed gauges on signal lines getting 300lbs pressure around 2000 kpa on both lines when full forward high idle so pressure is for sure reaching motor control just need know why they aren’t destroking when there is sufficient pressure to them to do so
The adjustment screws for rate of stroking are almost all way in is it possible that if they are screwed too far in it won’t destroke or I adjusted them out like two turns or three when we attempted to set them but is it possible that I might need back them off more or is even possible to tighten them to the point it won’t destroke? I was afraid of backing them out too far didn’t know if that was possible
This is a cross section of the motor controller from SIS. The signal pressure is in brown at the top. As you can see, it is dead headed at the controller and only moves the servo spool.
You can safely remove the end of the controller to inspect the internal components. You will lose a bit of oil though.
You can safely remove the end of the controller to inspect the internal components. You will lose a bit of oil though.
pittsburgh cat man
Senior Member
I have a question did you change the whole over ride valve with a reverse drive valve or just the solenoid ?
If we refer back to the graph (which is actually more than technical gobbledegook) we can see that both pump and motor see the same signal pressure. The pump is designed to upstroke from 30 - 115psi, at which point you will be moving at approx 3.5kMh. The fact you can get to about this speed with the signal line to the motor blocked means the pumps seem to be working OK.
From 115 - 217 psi, the motors take over by destroking.
To say that the
is kind of missing the point. It's not the case that the pumps somehow control the motors and the motors aren't allowed to destroke until the pumps are fully upstroked. It's just the way the system is designed, with the motors taking over at the pressure the pumps finish upstroking.
The whole valve and selenoid I swapped
Ok got ya I thought that was what it meant but wanted make sure I wasn’t missing something there
pittsburgh cat man
Senior Member
On opposite end of motor controller from the stroking adjustment there is a plug where you can put a tap for de stroke oil pressure. since we have signal pressure might be worth checking
I seen that in book was wondering same thing what is pressure there saposed to be ?
Was reading in stuff nige sent about drive motors and seen it says pressure adjustment screw limits max speed and minimum angle stop screw also limits top speed I understand the minimum angle stop screw but I see nothing in the picture above it that shows pressure screw any idea what book is talking about am I missing something
