1999 Bobcat 331

   #1  

kclark2227

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Does anyone know where I can find a service manual for this unit. I just bought it and need to get one. I also need to figure out what parts are needed to attach a hydraulic thumb. It is plumbed and has a bracket on the stick but that's it. Apparently in 1999 Bobcat didn't put everything but the thumb on like they do today and it seems a couple of parts are no longer made. So I will need to find an aftermarket kit or find some used parts.
 
   #2  

Woody65

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I have a 2005 331g that I bought without a thumb. The machine had a place for the top pin to go welded on from the factory. I just bought an aftermarket thumb for the machine and it went on in 15 minutes. If yours doesn’t have it, they make weld on aftermarket thumbs that can be used. Good luck.
 
   #3  

Woody65

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Don’t know if it will help but some pics.
IMG_20190916_150715551.jpg
IMG_20180827_162704070.jpg
IMG_20180916_103402265.jpg
IMG_20190916_150636231_HDR.jpg
 
  
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#4  
OP
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kclark2227

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Kannapolis, NC
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Kubota L4701 4WD HST
Don’t know if it will help but some pics.
Thanks for the photos. From my understanding what mine might be missing is a relief valve for the aux side. It is my understanding that if I use it without it/them, my hoses will blow if I close the claw and don't stop before completely closed. and the valves they now longer offer. So I would have to get it used. I have also been told that mine has the bracket for the cylinder and it is plumbed so it might be a later '99 model where they were starting to add things on getting ready for 2000 models when they started offering everything on the 331's straight from the factory. All you had to do was add the actual thumb. I hope this makes sense. But I know I can get the cylinder and the thumb and I have the bracket and the lines are on the arm. But I need to figure out if there are any parts to the system that I need and hunt down what is no longer offered from the dealer new. Either some aftermarket part or get a part off of a scraped Bobcat unit.
 
   #5  

laurencen

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regarding relief valve, if there was no valve you would have blown a hose a long time ago every time you bottom any cylinder on the arm
 
  
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#6  
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kclark2227

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regarding relief valve, if there was no valve you would have blown a hose a long time ago every time you bottom any cylinder on the arm
Correct. I just bought this 331 and it doesn't have the thumb. It is plumbed on the stick and has the bracket. I was told that the '99 units didn't come from the factory actually ready for a thumb. That was supposedly changed in 2000. But was also told for a '99 it shouldn't have a bracket on it. So I'm wondering if mine was late '99 unit where Bobcat was transitioning over to the 2000 units. Mine may well be ready for a thumb but I don't want to try and then it not be ready and I blow everything. I know I was told mine probably won't have a relief valve but I want to look just to see but don't know where it should be.
 
   #7  

Woody65

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From what you have said, I would believe, since the unit is already plumbed for aux hydros and has the bracket for the pin on thumb that it is ready to go. It probably has had a thumb on it during its lifetime.
 
   #8  

Woody65

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If you can’t find out for sure if a relief valve is present on the aux hydro lines, If and when you get a thumb for it, extend the thumb about 3/4 of the way and then curl your bucket. If the bucket is able to fully extend, push the thumb, and not blow a hose, the system is set up for a thumb. My 2 cents. Good luck
 
   #9  

Seven Gables

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Correct. I just bought this 331 and it doesn't have the thumb. It is plumbed on the stick and has the bracket. I was told that the '99 units didn't come from the factory actually ready for a thumb. That was supposedly changed in 2000. But was also told for a '99 it shouldn't have a bracket on it. So I'm wondering if mine was late '99 unit where Bobcat was transitioning over to the 2000 units. Mine may well be ready for a thumb but I don't want to try and then it not be ready and I blow everything. I know I was told mine probably won't have a relief valve but I want to look just to see but don't know where it should be.
Have you located the spool valve for your auxiliary lines? You’re port relief valves if the machine is equipped will be on this control valve. There should be two , one for each port. Look for a Allen head set screw with a jamb nut , that’s your port relief. If it has them the one that goes to the base end of your thumb cylinder will need to be adjusted with a pressure gauge. Set the set screw to relief at less than your thumb cylinder pressure rating. Post a pic of the auxiliary valve if possible
 
  
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kclark2227

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Kannapolis, NC
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Kubota L4701 4WD HST
Have you located the spool valve for your auxiliary lines? You’re port relief valves if the machine is equipped will be on this control valve. There should be two , one for each port. Look for a Allen head set screw with a jamb nut , that’s your port relief. If it has them the one that goes to the base end of your thumb cylinder will need to be adjusted with a pressure gauge. Set the set screw to relief at less than your thumb cylinder pressure rating. Post a pic of the auxiliary valve if possible
Where would this be? I have the instructions for the Clamp Kit and remote relief valve kit. The instructions on Page 2 from Bobcat are contradicting themselves. On page 2, it says "On Early Model Excavators: A remote relief valve kit will need to be ordered and installed on the following serial numbers: 331 (S/N 512913973 & Below and S/N 511920001 & Above)". My S/N is 512917785 which is not included in either group so your assume I'm good to go. But turn to Page 8 for Relief Valve Installation. For 331 Relief Installation S/N 512912001-512913973 start on page 11 and for 331 S/N 511920001 & Above and S/N 512911001 - 512911999 start on Page 12. I would think that I would fall into the page 12 list since mine is above 511920001. But then below that it says "For Models 331 (S/N 234313000 & Above) the relief valves are factory installed in the control valve. Which means that mine would have it. So I am absolutely confused as to whether I have the relief valve or not.
 
 
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