I am new to this forum. I took apart my pump because of poor performance and would not turn at all. While I had the pump off I cleaned the bronze filter and done what I thought was a great job finishing the swash plates. I put it back together today and now it won't move at all. No squealing or anything. The rest of the hydrolics work great. Any ideas? I didn't disturb the rotation group at all. Any help will be greatly appreciated!!
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coreya3212
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Welcome to the forum. Wish I could help, but my knowledge of pumps would only make it worse. Someone will be along to help you out.
The drive system seems to bleed faster than the hydrostatics actually. I found i had drive power mefore my hydraulics worked correctly.
How bad was the scoring?
Silly question, but did you put the wear plates back in the side they came out of?
If the scoring was bad, the face of the rotating group may hev been worn to, if it is, you needed to flatten it too.
The scoring was pretty bad. I should have taken pictures. I was careful not to mix up the plates and even though they had several grooves wore in them the rotating group side seemed to be ok. I couldn't feel any grooves in it. It is basically the same as it was before I took it apart in the first place. I would have thought that sanding the swash plates would have made some kind of difference given how bad they were grooved. What should I do next? Even thought the lift works I tilted the bucket to get the front wheels off the ground and when you put weight on the hydraulics they don't hold tight they are bouncy like an air cylinder. Does that make since?
I forgot to add that when I have it lifted the wheels will move independently but when its on the ground no matter which lever you move it goes in a strait line like you are pulling both levers forward and reverse.
Should I be able to turn the wheels? With it jacked up I can turn the wheels on both sides with my hands.
The noise will be air, the wheels should not be able to turn by hand. When they are full of fluid they should not be able to be turned by hand. When there is an air lock the wheel will turn and make a growl sort of sound and you can feel like a shake in the wheel as you rotate it.
How did you flatten the plates? a sheet of glass and wet and dry?
I'm having issues with mine too, one side moves faster than the other, new rotating groups and wear plates..... So you are not alone with pump/motor problems....
I keep thinking that it must be a blockage at a filter or valve somewhere but I don't know where to get a parts breakdown for my pump. I think tomorrow I am going to pull it back apart and see what else I can find. When I first put the pump back on after surfacing the plates it wouldn't move at all until I took the bronze filter out of the port block. I used a dual action sander to knock down the gunk and get the plates close, then I put a big piece of emery cloth down on a flat piece of steel and rubbed my plates over the top of it in a circular motion. I didn't do anything to the rotating group side but since the symptoms really didn't change I'm thinking that the plates didn't have anything to with it in the first place. My left side drive is a little faster than the right but neither side has enough torque to pull the machine over a block of wood. It sucks though because the lift works great and the motor runs strong. If I could just get the drive working I could put it to work. Are you having drive power issues as well?
did you have the replenishing valves out? were the pistons in the rotating group scored ?
one other how about the charge pressure spring and pressure .
I only took out the plates. I didn't disturb any of the other parts. I thought given how bad the wear plates were that I didn't need to go any further, not to mention the fact that this is the first time I have ever worked on any kind of hydraulics. What am I looking for when I take the pump apart? I was able to figure out how to take out the wear plates based on pictures I found in another post. As far as the pressure goes I don't know how to check it or where you check it
I should have been better informed before I took the pump apart. Are there common problems that any of you guys have with the drive on your machine?
OldMachinist
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I uploaded the section of the repair manual for your Vickers pump here. http://www.mediafire.com/?ny4iyojejky I hope it helps.
That manual is great! Thank you very much! It will be much easier to tear into it tomorrow with this. The only other question I had is I hear the term replunishing valve a lot. Where is it or does it have a different name in this manual?
If you had severe grooving in the plates from debris where did it come from and were you able to flush it all out? If you resurface the plates the usual way it will take hours and several changes of emery paper. Do not use a hand power tool on them as they must be very smooth and flat when done. I redid mine in the 632 and they work much better after but it takes time to do it. Check all the relief valves to see if there may be some debris holding one open a bit also. good luck with this.
I didn't get crazy with the sander. After I knocked down the rough stuff it still took three hours for the worst plate and around an hour for the other. Me and three other guys took turns sanding them across the cloth. If I would have had to sand them by my self I think it would have took me a full day to do both. I poured fluid in the pump body and dumped it back out is how I flushed it. I should have done a better job while I had it apart but I was afraid I wouldn't be able to get it back together if I went too far. I plan on pulling it again in the morning now that I have the manual and start going through it good. I will keep everyone posted on the progress as I get there. Thank you all for the support and if anyone else has any words of wisdom please feel free to chime in. This is my first bobcat experience so I take all of the advise I can get.
OldMachinist
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Item 32 on the parts breakdown is the high pressure relief/replenishing valve.
If you had deep wear, the face of the rotating groups may be a little worn too.... It could be bronze particles, but generally they are so small that they go through the system and get caught up on the main hydraulic filter, hopefully its not throughout the system.
Just ensure you clean everything with solvent and compressed air. Petrol (gas) works really well here, it dries without residue, a tip i was given and works really well. Lube all parts with oil before assembily.
