I have a Bobcat 742 that seems to move too slowly and there is excessive noise and vibrations from the hydraulics. I had massive leaks in the pump last year so I pulled the pump out and had it rebuilt. I spoke with the pump guy today and although he didn't have the chance to see it and try it himself, his thoughts were that it sounded like the pump was starving for oil. I am using 10W 40 like the manual states and I know I have a tiny leak at the suction hose going into the hydraulic pump for the boom and curl. I don't feel that this leak is significant enough to starve the pump, but he definitely told me to take care of this first. I am nervous that the pump is cavitating and I don't want to run it anymore. When I say it's slow, it's actually quite slow when compared to my neighbor's 763. It will not go faster than walking pace. It still has power though and it will bog the engine down when driving into a pile (can spin all four wheels) or counter-steering so I'm assuming the hydrostatic drives are still working okay. I plan to remove the port block from the reservoir to check for obstructions soon, but I'm hoping someone can point me to a better direction than this crapshoot I'm starting. Also, I don't have the square block so the bronze filter trick is out. Also, is there a trick to pulling lines off and not making a complete mess? One of my biggest hesitations is the mess created every time you pull a line. If there's a trick, please share. Thanks in advance.
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Oh yeah...one more tidbit of information. Sometimes the controls get so jerky that I have to let go of them completely because the bucking gets very violent. I have been able to witness the unit actually surging while I just hold the sticks in a constant position. It's usually only after a directional change.
The 74x series wasn't the fastest machine around, the newer model you spoke about is quicker, not a whole lot but it does move faster.Oh yeah...one more tidbit of information. Sometimes the controls get so jerky that I have to let go of them completely because the bucking gets very violent. I have been able to witness the unit actually surging while I just hold the sticks in a constant position. It's usually only after a directional change.
The bucking, check your steering linkages, if there is wear in the rubber and steel bushings, it can cause it to jump around like you spoke about. Also check the pintle arms are tight on the pump, if there is any slop in these points, things will jerk.
Check your reserve tank after running it a bit, see if it's foamy at all. If so, you are either pulling in air or your pump is cavetating.
https://youtu.be/C3SLvWclPic This link mine but it sounds about like this.The 74x series wasn't the fastest machine around, the newer model you spoke about is quicker, not a whole lot but it does move faster.
The bucking, check your steering linkages, if there is wear in the rubber and steel bushings, it can cause it to jump around like you spoke about. Also check the pintle arms are tight on the pump, if there is any slop in these points, things will jerk.
Check your reserve tank after running it a bit, see if it's foamy at all. If so, you are either pulling in air or your pump is cavetating.
That isn't a great sound, but i have heard it before. It could be pump wear causing it to cavetate.https://youtu.be/C3SLvWclPic This link mine but it sounds about like this.
The drive pump has a wear plate that the rotating group runs on. If you have any mechanical abilities you can repair this.
Pumps were just rebuilt on mine. The technician said the components were at the lower limits of the serviceable life.That isn't a great sound, but i have heard it before. It could be pump wear causing it to cavetate.
The drive pump has a wear plate that the rotating group runs on. If you have any mechanical abilities you can repair this.
And I should mention I checked the reservoir after running it and I found no foaming. I am overheating the engine though but i dont feel that's related.Pumps were just rebuilt on mine. The technician said the components were at the lower limits of the serviceable life.
Ah, it was looked at already. If you have the ability, i can run you through the details of flattening your wear plates to hopefully fixing this issue.And I should mention I checked the reservoir after running it and I found no foaming. I am overheating the engine though but i dont feel that's related.
Tazza...I'm confused. Aren't the wear plates in the pumps? If so, I just had them rebuilt. I assumed this was part of that.Ah, it was looked at already. If you have the ability, i can run you through the details of flattening your wear plates to hopefully fixing this issue.
If it was rebuilt then yes, they should have replaced them as you did say that they noted that there was wear. Did they give you a report of what was done?Tazza...I'm confused. Aren't the wear plates in the pumps? If so, I just had them rebuilt. I assumed this was part of that.
If the pump was fully rebuilt, the only other part that it could be are the drive motors.
I do not have a report, but it was $1700 which should've covered a lot I would think. I am waiting for a radiator hose to come so I can't test it yet, but I did think of something to try. I backed the centering spring out for the steering linkage to get a little more travel from the sticks. I've noticed it seems to have a little more speed when I push them harder so I think there might be a little more available but the spring is stopping the sticks from full movement. We'll see.If it was rebuilt then yes, they should have replaced them as you did say that they noted that there was wear. Did they give you a report of what was done?
If the pump was fully rebuilt, the only other part that it could be are the drive motors.
For that price, I believe all the worn parts were done.I do not have a report, but it was $1700 which should've covered a lot I would think. I am waiting for a radiator hose to come so I can't test it yet, but I did think of something to try. I backed the centering spring out for the steering linkage to get a little more travel from the sticks. I've noticed it seems to have a little more speed when I push them harder so I think there might be a little more available but the spring is stopping the sticks from full movement. We'll see.
Ensure the spring does not fully bind up either forward or backward. Use a torch, some light should be able to be seen.
If the bushings are worn, the sticks may hit the cover that they pass through. I have had this stop me before too.
Sorry...I hate when people don't follow through with their results. I did get more speed out of it by backing off the spring so it was bottoming out and not allowing the sticks to go fully forward or back. I still have quite a bit of noise, but I'm not seeing any foam so I'm going to focus on getting all of the little leaks tightened up and try to figure out why this thing is overheating so badly. PatFor that price, I believe all the worn parts were done.
Ensure the spring does not fully bind up either forward or backward. Use a torch, some light should be able to be seen.
If the bushings are worn, the sticks may hit the cover that they pass through. I have had this stop me before too.
