Pump for 631

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Leftyp

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Joined
Jan 21, 2008
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4
i have a 631 and i think i might need a new pump and motor just wondering if anyone knows what type of pump and motor they put in here..? i ordered a book from ebay just tryin to get a head start on it.. i went to a bobcat dealer to get a new filter and the guy was like you got bigger problems then that filter.. this thing is old and the filter was dirty and im sure trash got down it there.. but i had a guy tell me that the pumps hold up pretty good from what i gathered its a Vickers vane pump but thats it.. any help..??
 

Tazza

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Joined
Dec 7, 2004
Messages
16,840
Ok, so you replaced the filter?
Does your drive still work? do you have heaps of power etc? is it just the hydraulics giving you trouble?
You can get a re-conditioned double transmission pump for about $2,300 and the vane pump cartrage is around the 200 mark, not sure if it comes with the transmission pump or not.
Look at: http://www.skidloaderpumps.com/servlet/the-Bobcat-cln-before-1990/Categories
On the second page it shows the hydrostatic pump. Its a TA1919 pump with the hydraulic pump stuck on the front.
Like i said, i would start by checking that the hydrostats work, if they do you can look at the hydraulic pump. Its easy to pull apart, look for wear in the form of bumps in the cam plate (the centre section the vanes run in) Small scratches will not be a problem as the vanes wear into these and the pump works just fine. But if you have bumps in it, the oil will by-pass causing lower pressure.
What sort of crud came out of the filter? If its the hydro pump or drive motors it will be metal, if its the hydrostats it will be brass.
Don't go out and buy a new pump because you *think* its broken. These pumps can be brought back to life with a few hours worth of elbow grease. The hydraulic pump can be repaired for around $200.
 

jerry

Well-known member
Joined
May 3, 2007
Messages
2,043
Ok, so you replaced the filter?
Does your drive still work? do you have heaps of power etc? is it just the hydraulics giving you trouble?
You can get a re-conditioned double transmission pump for about $2,300 and the vane pump cartrage is around the 200 mark, not sure if it comes with the transmission pump or not.
Look at: http://www.skidloaderpumps.com/servlet/the-Bobcat-cln-before-1990/Categories
On the second page it shows the hydrostatic pump. Its a TA1919 pump with the hydraulic pump stuck on the front.
Like i said, i would start by checking that the hydrostats work, if they do you can look at the hydraulic pump. Its easy to pull apart, look for wear in the form of bumps in the cam plate (the centre section the vanes run in) Small scratches will not be a problem as the vanes wear into these and the pump works just fine. But if you have bumps in it, the oil will by-pass causing lower pressure.
What sort of crud came out of the filter? If its the hydro pump or drive motors it will be metal, if its the hydrostats it will be brass.
Don't go out and buy a new pump because you *think* its broken. These pumps can be brought back to life with a few hours worth of elbow grease. The hydraulic pump can be repaired for around $200.
Tazza, on this same subject when I got my 632 I changed the hyd oil filter and found it collapsed internally so I took out the bronze filter and it had about 1/3 of it covered with dirt and fine metal wire particles which I think came from the filter. The book said if the bronze filter was dirty that you should remove the port block also and clean it also, do you think that is necessary if you keep things clean as you change the filter? I didn't do it but maybe should have? thanks
 

Tazza

Moderator
Staff member
Joined
Dec 7, 2004
Messages
16,840
Tazza, on this same subject when I got my 632 I changed the hyd oil filter and found it collapsed internally so I took out the bronze filter and it had about 1/3 of it covered with dirt and fine metal wire particles which I think came from the filter. The book said if the bronze filter was dirty that you should remove the port block also and clean it also, do you think that is necessary if you keep things clean as you change the filter? I didn't do it but maybe should have? thanks
The filter would catch any dirt/metal particles before they got to the pump, thats what its there for so i really see no reason to pull the port block off.... Its almost as if the main filter was never changed for it to collapse! it would need to get pretty plugged up for it to do that.
I would just change the filters and see how things work, check your drive is working and if you still have hydraulic issues you may even want to check your relief valve just to be sure nothing is stuck, this could cause low pressure.
 

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