wateka
Well-known member
- Joined
- May 25, 2022
- Messages
- 123
Short answer: 6634488 is a PS1600-32 seal.
If you are rebuilding your hydrostatic motor and mangle the piston seal that comes with the seal kit, there are no extras. I was using an engine piston ring compressor to insert the piston but pushed too hard when I was positioning the piston to install the second seal. That pushed the ring into the center of the pump, where there is no bore. See the pic for a visual explanation. Do not install both seals and then try to just install the piston. You'll mangle them both trying to fit them in the bore. Install one, using a piston ring compressor, and then gently push the piston through to expose the other ring gap. Install the second o-ring and seal and use the piston ring compressor again.
The Bobcat part number for the seal and o-ring is 6634488, but Bobcat did not have any, and the one I saw on EBay looked too old to gamble on.
Since Danfoss made these motors, I found their part numbers, but no luck finding one either. I then called Danfoss customer service and found a guy who looked up the part number and there was a drawing he could see showing the dimensions and the only text on the drawing said T-Lon.
Google told me that T-Lon is a seal manufacturer so I called their sales dept and gave them the Danfoss part number. That guy said that could have been years ago because they don't have that part number but that it was a generic seal with many manufacturers. He suggested Hercules Sealing Products. Bingo.
If you are rebuilding your hydrostatic motor and mangle the piston seal that comes with the seal kit, there are no extras. I was using an engine piston ring compressor to insert the piston but pushed too hard when I was positioning the piston to install the second seal. That pushed the ring into the center of the pump, where there is no bore. See the pic for a visual explanation. Do not install both seals and then try to just install the piston. You'll mangle them both trying to fit them in the bore. Install one, using a piston ring compressor, and then gently push the piston through to expose the other ring gap. Install the second o-ring and seal and use the piston ring compressor again.
The Bobcat part number for the seal and o-ring is 6634488, but Bobcat did not have any, and the one I saw on EBay looked too old to gamble on.
Since Danfoss made these motors, I found their part numbers, but no luck finding one either. I then called Danfoss customer service and found a guy who looked up the part number and there was a drawing he could see showing the dimensions and the only text on the drawing said T-Lon.
Google told me that T-Lon is a seal manufacturer so I called their sales dept and gave them the Danfoss part number. That guy said that could have been years ago because they don't have that part number but that it was a generic seal with many manufacturers. He suggested Hercules Sealing Products. Bingo.
