763 Motor Carrier Seals

[bttpe]

I will be replacing motor carrier seals for the 2nd time on my 763. This all stems from pushing the hydro fluid into the chaincase. When we removed the original set it did appear that one seal was rolled on the shaft but that's only a guess it could have done that during removal. Installation did not go smoothly. It is cold here 30's and we struggled to fit the seal over the shaft. Our latest progression was to build up tape on a 2" PVC pipe so that we could push the seal on the shaft. Then drive it home with a 3" PVC coupling. Some of you might suspect that the motors are leaking excessively. I doubt that is the case. We had the motor - pump - drive motors out and ran it outside of the machine and had zero fluid bypass out of the motors. Obviously, this is a "no load" condition and that there will be more leakage under load but I don't believe that it could be excessive. (If you look back on my posts we had the same problem on a 753 and never resolved it... to the point that we sold the machine. Does anyone see something I'm missing on installing the seals? I talked to Bobcat Service and they didn't have any suggestion other than pay them the $1000 they would charge to diagnose and replace the seals)

 

[anthonyobrienjhb]

I know that this is an old thread, but this seems to come up regularly.

I found this under Carrier Shaft Seal Replacement in the service manual for the 773:

"
Note: before reinstalling the hydrostatic motor, check the plug located in the centre of the carrier shaft for tightness. If the plug becomes loosened, case drain lubrication oil from the hydrostatic motor can leak into the chaincase.
"

No guarantees, but worth checking if chaincase is filling with oil.

Image attached...