Hydraulic fluid leak into gear box 642B

Wild Bill @ Deadwood · Mar 30, 2025

My older 642B is leaking hydraulic into the chain drive box at an alarming rate. I fill up the hydraulic tank and I can run about 15 to 20 minutes before experiencing steering and raising the bucket failure. I have removed both chain drive motors and cannot visibly see any issues with the motor driveshaft seals. Serial # for my 642b is 5040-M-26786. The chain drive motor numbers are left side #6656 and right side 6763 product of Char-Lynn E.T.N Eaton Corp..... Hope someone can provide me a direction for resolving this issue. Thanks,,,,, Bill R.

brdgbldr · Mar 30, 2025

Wild Bill @ Deadwood said:
My older 642B is leaking hydraulic into the chain drive box at an alarming rate. I fill up the hydraulic tank and I can run about 15 to 20 minutes before experiencing steering and raising the bucket failure. I have removed both chain drive motors and cannot visibly see any issues with the motor driveshaft seals. Serial # for my 642b is 5040-M-26786. The chain drive motor numbers are left side #6656 and right side 6763 product of Char-Lynn E.T.N Eaton Corp..... Hope someone can provide me a direction for resolving this issue. Thanks,,,,, Bill R.

It's most likely internal seals in the motor that are letting too much pressure by and the fluid is just blowing past the external seals.

Take a look at the schematic for your drive motors in the parts catalog:

Bobcat Parts Catalog - Find Diagrams for Your Equipment - Bobcat Company

Locate all parts and component information about your Bobcat equipment with detailed visual diagrams and illustrations with parts numbers and add to your list.

partscatalog.bobcat.com

Hydraulic fluid leak into gear box 642B

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